Prenatal Environmental Factors Research Paper

Prenatal Environmental Factors Research Paper

The environment can have an important influence on development, and this also includes the prenatal period. The growth that happens during the nine months of prenatal development is nothing short of astonishing, but this period is also a time of great vulnerability. Fortunately, the effects of many of these hazards can be greatly lessened or even avoided entirely. While dangers do exist, the vast majority of babies are born healthy. Prenatal Environmental Factors Research Paper

Today, researchers understand a great deal about teratogens, a term used to describe the broad range of conditions and substances that can increase the risk of prenatal problems and abnormalities. Teratogens can cause a wide range of problems from low birth-weight to brain damage to missing limbs. In order to minimize and avoid these dangers, it is essential to understand what poses a risk to the fetus and how such dangers can affect development.

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Diseases That Can Impact Prenatal Development

Many diseases are capable of injuring a growing fetus. For example, doctors discovered that when a mother contracts rubella (also known as the German measles) early in her pregnancy, her child might suffer blindness, heart abnormalities, and brain damage as a result. Prenatal Environmental Factors Research Paper

During the 1960s, a rubella epidemic led to nearly 20,000 infants in the United States being born with impairments linked to the disease. Since then, immunizations have dramatically decreased ​the incidence of rubella and lowered the number of children affected by the illness.

Medications That Can Impact Prenatal Development

In the past, doctors believed that the placenta served as a barrier to protect the growing fetus against toxins. During the 1960s, a number of pregnant women were prescribed the drug thalidomide which caused more than 10,000 infants to be born missing legs, arms, or ears. The birth defects caused by the drug made the dangers of certain medications very clear.

Today, doctors recognize the teratogenic effects of many medicinal drugs including anticonvulsants, tetracycline, anticoagulants, bromides, and most hormones. Prenatal Environmental Factors Research Paper

Because of the potential dangers, it is important for pregnant women to avoid any medications that have not been specifically recommended by their doctor. You have also probably noticed that most television ads for new medications include some type of statement warning that women who are pregnant or who may become pregnant should avoid taking the drug.

Because such medications are thought to be able to affect the fetus as early as 10 to 14 days after conception, it is essential to cease taking certain medications if you think you may become pregnant. Fortunately, because doctors and mothers-to-be are far more aware of the potential dangers, the rates of medication-linked birth defects have been reduced considerably over the past few decades. Prenatal Environmental Factors Research Paper

Psychoactive Drugs That Can Impact Prenatal Development

Unfortunately, prenatal damage caused by psychoactive drugs such as alcohol, cocaine, heroin, inhalants, and tobacco are still far too common. All psychoactive drugs have a deleterious effect on prenatal development leading to problems including low birth-weight, premature birth, and impaired brain development. The effects of such drug use can lead to both short-term and long-term deficits. Babies exposed to psychoactive drugs in-utero may show signs of drug withdrawal after birth, such as crying, startling, difficulty sleeping, and erratic eating.

As they continue to develop and grow, these children may face learning problems such as an inability to pay attention, poor self-control, increased irritability, or even major developmental delays.

What impact can these psychoactive substances have on development? Prenatal Environmental Factors Research Paper

  • Tobacco use can result in low birth-weight as well as an increased risk of abnormalities such as urinary tract and limb malformations.
  • Alcohol use during pregnancy causes fetal alcohol syndrome which is characterized by facial abnormalities including a smaller than average head size, a flattened nose, wide spacing between the eyes, and a narrow upper lip. Fetal alcohol syndrome also results in intellectual impairments, impaired physical growth, learning disabilities, and behavioral problems.
How to Minimize Environmental Dangers

Fortunately, the effects of many environmental dangers can be minimized or even avoided entirely. Thanks to increased awareness of the effects of diseases, medications, and drugs, mothers are able to better ensure that they are healthy and free of harmful substances by the time they conceive a child.

While environmental dangers pose a definite risk to the growing fetus, they do not always cause harm. The impact of such hazards involves the interaction of a number of factors, including the timing of the exposure, the duration of the exposure, and possible genetic vulnerabilities that may be present. Prenatal Environmental Factors Research Paper

The specific time of when the growing organism is exposed to the danger can play a major role in the ultimate outcome. Throughout prenatal development, there are times of greater susceptibility known as critical periods. For example, an embryo is most vulnerable to teratogens in the first eight weeks after conception. However, damage to major areas of the body including the brain and eyes can also occur during the later weeks of pregnancy.

In addition to abstaining from drugs, alcohol, medications, and other substances, proper medical care, social support, and postnatal care can all play an important role in minimizing the dangers of environmental toxins. Prenatal Environmental Factors Research Paper

Recent investigations suggest that certain factors play an important role in the development of a child during the prenatal period. This article aims to examine the factors affecting prenatal development, significantly, before and during pregnancy with respect to the development of a child’s personality at later stages of life. The Sunnah and contemporary psychology highlight a number of factors that may have a direct or indirect impact on maternal and fetus health. The Sunnah explicitly discusses these factors from a religious and humanistic paradigm for maternal-child health and care during pregnancy. Conversely, contemporary psychologists examine such factors based on the investigations conducted during pregnancy. In order to provide a comprehensive overview of the issue, this research employs content analysis methodology to find out commonalities and differences between the authentic traditions (Hadiths) of the Prophet Muhammad (peace be upon him) and contemporary psychological studies and research. Prenatal Environmental Factors Research Paper This study attempted to integrate the religious and psychological perspectives on mother-child health care strategies, therefore, is considered beneficial for humanity specifically for Muslim communities globally. The findings of this article suggest that physical, psychological, religious, and social factors may affect the mother and her fetus respectively from the Sunnah domain. On the other hand, psychological studies stress the physical, psychological, and social factors with no emphasize on the religious aspects, which are key determinants to affect the mother and her fetus during pregnancy. This endeavor also gives an extensive insight into the factors influencing the development at the prenatal period from a mother-child care perspective, and hopefully, will serve humankind particularly Muslim parent to take care of their children during prenatal stage. Prenatal Environmental Factors Research Paper

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The placenta attaches a fetus to a woman's uterine wall, bringing maternal blood vessels close to fetal vessels. Important nutrients and other positive factors pass from the mother's blood into the fetal blood, helping support fetal growth and development. Although the placenta also contains a special protective filter, or barrier, some potentially negative factors can pass from maternal into fetal blood, possibly harming the fetus. If you're pregnant or thinking of becoming pregnant, talk to your doctor about how best to protect your fetus and help ensure a healthy newborn.

Mother's Nutrition

Maternal blood carries glucose that crosses the placenta, providing energy for fetal metabolism. It also contains amino acids, which also cross the placenta and help produce proteins needed for fetal development. Finally, factors called "growth factors" also cross from the mother's blood into fetal blood; they help support development of many different fetal tissues. (ref3p2)

If a pregnant woman becomes malnourished, the fetus might not get sufficient nutrients or other factors, slowing its growth and possibly resulting in an underdeveloped newborn. (ref1p98) If maternal blood glucose is too high, the mother might develop gestational diabetes, which could cause the baby to be too large and have a difficult birth. (ref2) Prenatal Environmental Factors Research Paper

Maternal Age and Health

A mother's age can also affect the fetus, with older women at increased risk of fetal problems. A study in the "Western Journal of Medicine" in November 2000 evaluated fetal loss due to stillbirth, spontaneous abortion or other problems in more than 600,000 Danish women. The authors found increased negative outcomes in women older than 35, with about 1/5th of their pregnancies resulting in loss of the fetus, compared to younger women; this increased to more than half by age 42. (ref9)

Research also indicates that a woman's overall health impacts her pregnancy. For example, a 2013 study in the "Journal of Obstetrics and Gynecology Canada" found that obese women, at higher risk themselves of hypertension and other problems, were also more likely to have babies with low birth weight or metabolic problems, compared to women of average weight. (ref10) Prenatal Environmental Factors Research Paper

Lifestyle Impact

Alcohol crosses from the mother's blood into the fetal circulation and, according to a study published in November 2005 in "Obstetrics and Gynecology," one in five pregnant American women indulge in binge drinking. (ref5) Drinking any alcohol during pregnancy can put the fetus at risk of problems called "Fetal Alcohol Spectrum Disorders," which can be moderate to severe. The negative impact on the fetus can include (ref6) poor growth, weak muscle tone, slow development of speech, or heart or facial malformation. (ref4)

Factors in cigarette smoke can also pass into fetal blood, causing potentially serious problems. Nicotine narrows blood vessels, slowing movement of oxygen and nutrients to fetal cells; along with other chemicals in smoke, it might cause low birth weight and increased risk of asthma, gastrointestinal problems or obesity in newborns. (ref7) A study published in February 2008 in "Nicotine and Tobacco Research" found that factors from smoke can also raise the risk of spontaneous abortion or premature birth, and might also cause fetal neurological problems. (ref8) Prenatal Environmental Factors Research Paper

Some Medications

Some prescription drugs that can cross the placenta might also have negative effects on the fetus. These include the antibiotic tetracycline, which can damage developing teeth, some blood-thinners that can slow nervous system development, and chemotherapy drugs. (ref1p145-6) Illegal drugs such as heroin are especially damaging during the early stages of pregnancy, but might also harm the fetus later in development, slowing fetal growth and causing premature birth or, in rare cases, fetal death.

What determines how a child develops? While it is impossible to account for each and every influence that contributes to who a child eventually becomes, what researchers can do is look at some of the most apparent factors. These include things such as genetics, parenting, experiences, friends, family, education and relationships. By understanding the role that these factors play, researchers are better able to identify how such influences contribute to development.

Think of these influences as building blocks. While most people tend to have the same basic building blocks, these components can be put together in an infinite number of ways. Consider your own overall personality. How much of who you are today was shaped by your genetic background, and how much is a result of your lifetime of experiences? Prenatal Environmental Factors Research Paper

This question has puzzled philosophers, psychologists, and educators for hundreds of years and is frequently referred to as the nature versus nurture debate. Are we the result of nature (our genetic background) or nurture (our environment)? Today, most researchers agree that child development involves a complex interaction of both nature and nurture. While some aspects of development may be strongly influenced by biology, environmental influences may also play a role. For example, the timing of when the onset of puberty occurs is largely the results of heredity, but environmental factors such as nutrition can also have an effect.

From the earliest moments of life, the interaction of heredity and the environment works to shape who children are and who they will become. While the genetic instructions a child inherits from his parents may set out a road map for development, the environment can impact how these directions are expressed, shaped or event silenced. The complex interaction of nature and nurture does not just occur at certain moments or at certain periods of time; it is persistent and lifelong.

In this article, we'll take a closer look at how biological influences help shape child development. We'll learn more about how our experiences interact with genetics and learn about some of the genetic disorders that can have an impact on child psychology and development. Prenatal Environmental Factors Research Paper

The Earliest Period of Development

At its very beginning, the development of a child starts when the male reproductive cell, or sperm, penetrates the protective outer membrane of the female reproductive cell, or ovum. The sperm and ovum each contain chromosomes that act as a blueprint for human life. The genes contained in these chromosomes are made up of a chemical structure known as DNA (deoxyribonucleic acid) that contains the genetic code, or instructions, that make up all life. Except for the sperm and ova, all cells in the body contain 46 chromosomes. As you might guess, the sperm and ova each contain only contain 23 chromosomes. This ensures that when the two cells meet, the resulting new organism has the correct 46 chromosomes.

How Environment Influences Gene Expression

So how exactly do the genetic instructions passed down from both parents influence how a child develops and the traits they will have? In order to fully understand this, it is important to first distinguish between a child's genetic inheritance and the actual expression of those genes. A genotype refers to all of the genes that a person has inherited. A phenotype is how these genes are actually expressed. The phenotype can include physical traits, such as height and color or the eyes, as well as nonphysical traits such as shyness and extroversion.

While your genotype may represent a blueprint for how children grow up, the way that these building blocks are put together determines how these genes will be expressed. Think of it as a bit like building a house. The same blueprint can result in a range of different homes that look quite similar but have important differences based on the material and color choices used during construction.

Factors That Influence How Genes Are Expressed

Whether or not a gene is expressed depends on two different things: the interaction of the gene with other genes and the continual interaction between the genotype and the environment. Prenatal Environmental Factors Research Paper

  • Genetic Interactions: Genes can sometimes contain conflicting information, and in most cases, one gene will win the battle for dominance. Some genes act in an additive way. For example, if a child has one tall parent and one short parent, the child may end up splitting the difference by being of average height. In other cases, some genes follow a dominant-recessive pattern. Eye color is one example of dominant-recessive genes at work. The gene for brown eyes is dominant and the gene for blue eyes is recessive. If one parent hands down a dominant brown eye gene while the other parent hands down a recessive blue eye gene, the dominant gene will win out and the child will have brown eyes.
  • Gene-Environment Interactions: The environment a child is exposed to both in utero and throughout the rest of his or her life can also impact how genes are expressed. For example, exposure to harmful drugs while in utero can have a dramatic impact on later child development. Height is a good example of a genetic trait that can be influenced by environmental factors. While a child's genetic code may provide instructions for tallness, the expression of this height might be suppressed if the child has poor nutrition or chronic illness. Prenatal Environmental Factors Research Paper
Genetic Abnormalities

Genetic instructions are not infallible and can go off track at times. Sometimes when a sperm or ovum is formed, the number of chromosomes may divide unevenly, causing the organism to have more or less than the normal 23 chromosomes. When one of these abnormal cells joins with a normal cell, the resulting zygote will have an uneven number of chromosomes. Researchers suggest that as many as half of all zygotes that form have more or less than 23 chromosomes, but most of these are spontaneously aborted and never develop into a full-term baby.

In some cases, babies are born with an abnormal number of chromosomes. In every case, the result is some type of syndrome with a set of distinguishing characteristics. Prenatal Environmental Factors Research Paper

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Abnormalities of the Sex Chromosomes

The vast majority of newborns, both boys and girls, have at least one X chromosome. In some cases, about 1 in every 500 births, children are born with either a missing X chromosome or an additional sex chromosome. Klinefelter syndrome, Fragile X syndrome, and Turner syndrome are all examples of abnormalities involving the sex chromosomes.

Kleinfelter's syndrome is caused by an extra X chromosome and is characterized by a lack of development of the secondary sex characteristics and as well as learning disabilities.

Fragile X syndrome is caused when part of the X chromosome is attached to the other chromosomes by such a thin string of molecules that it seems in danger of breaking off. It can affect both males and females, but the impact can vary. Some with Fragile X show few if any signs, while others develop mild to severe mental retardation. Prenatal Environmental Factors Research Paper

Turner syndrome occurs when only one sex chromosome (the X chromosome) is present. It affects only females and can result in short stature, a "webbed" neck and a lack of secondary sex characteristics. Psychological impairments associated with Turner syndrome include learning disabilities and difficulty recognizing emotions conveyed through facial expressions.

Down Syndrome

The most common type of chromosomal disorder is known as trisomy 21, or Down syndrome. In this case, the child has three chromosomes at the site of the 21st chromosomes instead of the normal two. Down syndrome is characterized by facial characteristics including a round face, slanted eyes, and a thick tongue. Individuals with Down syndrome may also face other physical problems including heart defects and hearing problems. Nearly all individuals with Down syndrome experience some type of intellectual impairment, but the exact severity can vary dramatically. Prenatal Environmental Factors Research Paper

Final Thoughts

Clearly, genetics have an enormous influence on how a child develops. However, it is important to remember that genetics is just one piece of the intricate puzzle that makes up a child's life. Environmental variables including parenting, culture, education and social relationships also play a vital role.

Developmental defects in animals may result in early embryonic death, fetal death, mummification, abortion and stillbirths, together with specific congenital defects relating to body systems. A congenital defect can be classified as a malformation, deformation or disruption. A malformation develops due to a defect which is intrinsic to the embryological differentiation or development of a structure. A deformation occurs due to an alteration in the shape or structure of a body part which had previously undergone normal differentiation. The term disruption refers to a structural defect which results from the destruction of a previously normal structure due to interruption of blood supply or to mechanical interference. Prenatal Environmental Factors Research PaperIn both human and animal populations, reproductive failure encompasses sterility, infertility, abortions, stillbirths and malformations. Fetal growth retardation and premature at birth may also indicate interference with normal in utero development. Congenital defects can be caused by genetic factors and environmental influences; the etiology of many of these adverse effects is unknown. In the human population, it has been estimated that close to 70% of congenital defects are of uncertain or unknown cause; approximately 20% may be due to genetic factors such as mutations and chromosomal abnormalities, and 10% can be attributed to teratogenic environmental factors such as chemicals, therapeutic drugs, certain poisonous plants and infectious agents. Reliable data relating to the occurrence of congenital defects in animal populations are not readily available. Estimates suggest that congenital defects in lambs, calves and foals occur to an upper limit of 3 to 4%. In dog populations, developmental defects are reported to affect approximately 6% of pups. Congenital defects are reported infrequently in cats. Some developmental defects in animals can be related directly to nutritional deficiencies, inbreeding, consumption of toxic plants, exposure to environmental pollutants or injurious physical factors and to infections with pathogenic microorganisms. The frequency of defects varies with species, breed, season of the year, geographical location and with the extent of ingestion of toxic substances and of exposure to deleterious physical factors or infection with teratogenic pathogens. If infection occurs at an early stage of gestation, serious congenital defects may follow. Infection of the fetus with pathogenic agents before it becomes immunologic ally competent may result in immunotolerance to that pathogen. If such fetuses survive to birth, they remain infected for life and do not produce an immune response to the infectious agent which caused the congenital infection. Prenatal Environmental Factors Research Paper  
Mutations

Mutations, which can be defined as changes in nucleotide sequences of genes, can occur spontaneously or may be induced by external influences. These changes can occur through the substitution, insertion or deletion of nucleotide bases and can be transmitted to future generations. Only a small subset of variants which occur naturally throughout the genomes of all vertebrates are associated with disease.

In a given animal population, mutations at gene loci occur de novo with a certain frequency per generation, known as the spontaneous mutation rate. This is typically one per million. Based on the underlying mechanisms which result in genetic change, mutations can be divided into two broad categories, spontaneous and induced. Spontaneous mutations result from errors in DNA replication and repair as well as from errors which occur during recombination or movement of transportable elements. Induced mutation is a consequence of accidental or deliberate exposure to chemical or physical agents or mutagens which can cause heritable alterations in DNA. Radiation can induce a variety of non‐specific chromosomal and DNA aberrations. Following exposure to chemical mutagens, agents which induce mutation, DNA replication is affected in a manner which increases the rate of mutation above background level. Prenatal Environmental Factors Research Paper

The simplest genetic models are exemplified by traits which are under the influence of single genes and conform to classic Mendelian principles (Table 28.1). Single genes can exist in a number of alternate states, termed alleles, which can be described as dominant, recessive, co‐dominant or partially dominant. A recessive allele is one whose phenotypic effect is not expressed in the heterozygote. The phenotypic effect of a recessive allele is expressed only in animals homozygous for that allele. Animals homozygous for a non‐functional tyrosinase gene exhibit the disease trait referred to as albinism. Tyrosinase is required for the production of melanin from tyrosine. Dominant alleles are phenotypically expressed in animals heterozygous for that allele. Some mutations which are incompatible with survival are termed lethal mutations. Such mutations invariably result in premature death and consequently are not passed on to subsequent generations. Gangliosidosis is an example of a recessive lethal gene resulting from an inherited deficiency in β‐galactosidase. This condition is not lethal in the heterozygous state. Some mutations in regions encoding for a gene product may not affect the animal’s viability. They may, however, ultimately affect the animal’s performance and increase the risk of disease in subsequent generations. Classically, animal breeders select animals for specific characteristics. Negative aspects of selective breeding include reduced variation, reduction in genetic fitness, increased homozygosity and potential for expression of undesirable characteristics within a given population. Prenatal Environmental Factors Research Paper

In most cases, prenatal development occurs normally and follows the established patterns of development with little variation. However, there are a number of things that can go wrong during this time, which are usually caused by genetics or environmental problems.

Genetic Problems 

As you might imagine, genetics play a major role in development. However, in some cases, genetic problems can emerge that may impact both current and future development.

  • Down Syndrome: Also known as trisomy 21, Down syndrome is the most common genetic anomaly during prenatal development. Down syndrome is caused by an extra copy of the 21 chromosomes (meaning there are three chromosomes instead of the usual two) and impacts approximately 1 out of every 1,000 infants. Typical features of Down syndrome include flattened facial features, heart defects, and intellectual impairment. The risk of having a child with Down syndrome increases with maternal age.
  • Inherited diseases: A number of illnesses can be inherited if one or both parents carry a gene for the disease. Examples of inherited diseases include Sickle-cell anemia, Cystic fibrosis, and Tay-Sachs disease. Genetic tests can often determine if a parent is a carrier of genes for a specific disease.
  • Sex-Chromosome Problems: The third type of genetic problems involves sex-chromosomes. These include conditions such as Klinefelter's syndrome (an extra X-chromosome) and Turner syndrome (a single X-chromosome). Prenatal Environmental Factors Research Paper

Environmental Problems 

Environmental variables can also play a major role in prenatal development. Harmful environmental elements that can effects the fetus are known as teratogens. There a number of teratogens that can harm the fetus, including:

  • Maternal Drug Use: The use of substances by the mother can have devastating consequences to the fetus. Smoking is linked to low birth weight, which can result in a weakened immune system, poor respiration, and neurological impairment. Alcohol use can lead to fetal alcohol syndrome, which is linked to heart defects, body malformations, and mental retardation. The use of illicit psychoactive drugs such as cocaine and methamphetamine is also linked to low birth weight and neurological impairment.
  • Maternal Disease: There are a number of maternal diseases that can negatively impact the fetus, including herpes, rubella, and AIDS. Herpes virus is one of the most common maternal diseases and can be transmitted to the fetus, leading to deafness, brain swelling, or mental retardation. Women with herpes virus are often encouraged to deliver via cesarean to avoid transmission of the virus. Prenatal Environmental Factors Research Paper

The prenatal period is a time of tremendous growth and also great vulnerability. As you have seen, there are a number of dangers that can pose a potential risk to the growing fetus. Some of these dangers, such as environmental risks from teratogens and drug use, can be prevented or minimized. In other instances, genetic problems may simply be unavoidable. In either case, early prenatal care can help new mothers and children cope with potential problems with prenatal development.

Prenatal Environment

Humans are mammals. We all learned this in elementary school. We also learned that as a mammal, we give birth to live children rather than laying an egg. Part of the reason the child develops inside the mother is to protect it from being harmed by the external environment. This means that the developing child is protected from all unwanted environmental hazards, right? Prenatal Environmental Factors Research Paper

The environment inside the uterus, where the unborn child is developing, is called the prenatal environment. Inside the uterus, the developing embryo and fetus are protected. The unborn child receives all it needs from the mother, including the nutrients that keep it healthy. The placenta is a temporary organ that joins the mother and fetus.

The placenta attaches to the mother's uterus and to the unborn child through the umbilical cord. It transfers oxygen and nutrients from the mother to the fetus and allows waste products to be eliminated from the fetus. This sounds like a pretty sheltered environment for an unborn child. Let's consider our question again. 'Is the developing child protected from all unwanted environmental hazards?'

Unfortunately, the answer to this question is no. Up until the 1960s, it was believed that the placenta also acted as a filter, to help keep anything unwanted or harmful from affecting the baby. We now know that potentially harmful substances can cross the placenta, and be transferred to the developing child from the mother. While the prenatal environment protects the embryo and fetus from a great many dangers, it cannot protect the unborn child from everything that the mother comes into contact with.

Drug, Alcohol and Tobacco Use

There are many potential hazards to the prenatal development of an unborn child. Many of these potential hazards are related to drug, alcohol or tobacco use. Alcohol, for example, can quickly cross the placenta and enter the unborn child's bloodstream in the same levels that it is in the mother's blood. Women who drink alcohol during pregnancy put their child at risk for fetal alcohol syndrome. This is a set of birth defects and disabilities related to alcohol consumption during pregnancy. Prenatal Environmental Factors Research Paper

Tobacco use during pregnancy can cause low birth weight and has been linked to higher rates of respiratory problems in children. Women who smoke are advised to stop if they discover they are pregnant or are trying to become pregnant. The use of illegal drugs can cause a variety of concerns for the health of an unborn child. Prenatal development can be slowed, birth defects or death of the unborn child can occur, and there is a higher risk for premature birth. Also, a child can even be born with an addiction.

It may seem obvious that illegal drug use could be harmful to an unborn child, but store-bought or prescription medications can be a hazard as well. A caregiver can help determine the benefit of a medication and whether it is greater than the risk that it may pose to the unborn child. The use of any medication that is a known teratogen should be avoided during pregnancy. A teratogen is a substance known to potentially cause a birth defect or cause a pregnancy to end.

Remember when we mentioned that before the 1960s it was believed that the placenta protected the developing child from harmful substances? The common use of the prescription drug Thalidomide (for morning sickness during pregnancy) changed this idea. A large number of infants with birth defects were born to women who were given this medication during pregnancy. Because of this, we now know that medications can have harmful effects on the prenatal environment. Prenatal Environmental Factors Research Paper

Autism is a devastating childhood condition that has emerged as an increasing social concern just as it has increased in prevalence in recent decades. Autism and the broader category of autism spectrum disorders are among the increasingly seen examples in which there is a fetal basis for later disease or disorder. Environmental, genetic, and genetics factors all play a role in determining the risk of autism and some of these effects appear to be trans generational. Identification of the most critical windows of developmental vulnerability is paramount to understanding when and under what circumstances a child is at elevated risk for autism. No single environmental factor explains the increased prevalence of autism. While a handful of environmental risk factors have been suggested based on data from human studies and animal research, it is clear that many more, and perhaps the most significant risk factors, remain to be identified. The most promising risk factors identified to date fall within the categories of drugs, environmental chemicals, infectious agents, dietary factors, and other physical/psychological stressors. However, the rate at which environmental risk factors for autism have been identified via research and safety testing has not kept pace with the emerging health threat posed by this condition. For the way forward, it seems clear that additional focused research is needed. But more importantly, successful risk reduction strategies for autism will require more extensive and relevant developmental safety testing of drugs and chemicals.

Developmental toxicity caused by exposure to a mixture of environmental pollutants has become a major health concern. Human-made chemicals, including xenoestrogens, pesticides and heavy metals, as well as unhealthy lifestyle behaviors, mainly tobacco smoking, alcohol consumption and medical drug abuse, are major factors that adversely influence prenatal development and increase susceptibility of offspring to diseases. There is evidence to suggest that the developmental toxicological mechanisms of chemicals and lifestyle factors involve the generation of reactive oxygen species (ROS) and cellular oxidative damage. Overproduction of ROS induces oxidative stress, a state where increased ROS generation overwhelms antioxidant protection and subsequently leads to oxidative damage of cellular macro molecules. Data on the involvement of oxidative stress in the mechanism of developmental toxicity following exposure to environmental pollutants are reviewed in an attempt to provide an updated basis for future studies on the toxic effect of such pollutants, particularly the notion of increased risk for developmental toxicity due to combined and cumulative exposure to various environmental pollutants. The aims of such studies are to better understand the mechanisms by which environmental pollutants adversely affect concept us development and to elucidate the impact of cumulative exposures to multiple pollutants on post-natal development and health outcomes. Prenatal Environmental Factors Research Paper

Developmental toxicity caused by exposure to mixture of environmental pollutants has become a major health concern. Human-made chemicals, including xenoestrogens, pesticides and heavy metals, as well as unhealthy lifestyle behaviors, mainly tobacco smoking, alcohol consumption and medical drug abuse, are major factors that adversely influence prenatal development and increase the susceptibility of offspring to development complications and diseases. There is evidence to suggest that the developmental toxicological mechanisms of human-made chemicals and unhealthy lifestyle factors involve the generation of reactive oxygen species (ROS) and cellular oxidative damage. Overproduction of ROS induces oxidative stress, a state where increased generation of ROS overwhelms antioxidant protection and subsequently leads to oxidative damage of cellular macro molecules. Exposure to various environmental pollutants induces synergistic and cumulative dose-additive adverse effects on prenatal development, pregnancy outcomes and neonate health. Data from the literature on the involvement of oxidative stress in the mechanism of developmental toxicity following in vivo exposure to environmental pollutants will be reviewed in an attempt to provide an updated basis for future studies on the toxic effect of such pollutants, particularly the notion of increased risk for developmental toxicity due to combined and cumulative exposure to various environmental pollutants. The aims of such studies are to better understand the mechanisms by which environmental pollutants adversely affect concept us development and to elucidate the impact of cumulative exposures to multiple pollutants on postnatal development and health outcomes. Prenatal Environmental Factors Research Paper

Significant research developments in the etiopathogenesis of schizophrenia have occurred during the past several years. One such advance is the "neurodevelopmental" hypothesis that events during early brain development, especially the prenatal and perinatal periods, may play an important causal role in at least some, and perhaps many, cases of schizophrenia. Consequently, the study of potential factors that could impair early brain development is likely to prove fruitful in identifying particular causes of this illness.

Converging lines of evidence in favor of the neurodevelopmental hypothesis of schizophrenia derive largely from three areas of schizophrenia research: brain imaging/neuro-pathology, premorbid abnormalities and minor physical anomalies.

ORDER A PLAGIARISM-FREE PAPER HEREBrain imaging and cytoarchitectonic studies have consistently demonstrated increased ventricular size and reduced volumes of medial temporal lobe structures, and abnormalities of neuronal number and organization in patients with schizophrenia (Waddington 1993a,b; Suddath and others; Bogerts and others; Akbarian and others). The fact that structural brain anomalies occur in "first episode" patients suggests that they are likely present before the onset of illness (Waddington 1993a). In addition, children destined to develop schizophrenia have increased neuromotor and psychosocial abnormalities, including social withdrawal, disruptive behavior and emotional lability (Walker and others; Jones and others). The third piece of evidence derives from studies of minor physical anomalies (MPAs), minor malformations of the head, eyes, ears, hands, mouth or feet that are ectodermal in origin, and that are thought to result from environmental or genetic insults in the first or second trimesters (Green and others). Investigations of MPAs are of relevance to schizophrenia, since ectodermal development closely parallels maturation of the fetal brain, and patients with schizophrenia, compared to controls, have an increased occurrence of MPAs (Green and others). Prenatal Environmental Factors Research Paper

The study of monozygotic (MZ) twins; discordant for schizophrenia has provided a critically important strategy to differentiate the relative contribution of genes and environment to adverse neurodevelopmental events. Because identical twins share all of their genes, any between-twin differences are presumed to be environmental in origin. In a landmark MRI study of discordant MZ twins, Suddath and colleagues demonstrated that almost every affected twin had increased ventricular size and diminished volumes of temporolimbic structures, including the hippocampus, compared to his or her respective unaffected twin. Further studies of discordant MZ twins, including investigations using positron emission tomography (PET) and dermal ridge counts (Bracha and colleagues), have provided additional evidence supporting environmental etiologies.

Although many different types of prenatal exposures are potential risk factors for schizophrenia, we shall focus upon three of the best studied: prenatal infection, prenatal nutritional deficiency and obstetric complications.

Prenatal infection.

It is well-known that many infectious agents have detrimental effects on fetal brain development. These infectious teratogens include rubella, cytomegalovirus (CMV), and herpes simplex virus (HSV) (Whitley and Stagno). With respect to developmental pathology, several concordant findings exist between congenital infection syndromes resulting from these viruses and schizophrenia, including brain and dermatoglyphic abnormalities. Prenatal Environmental Factors Research Paper

Many epidemiologic studies support a potential role for prenatal viral insults in schizophrenia. One of the first major pieces of evidence is the consistent demonstration of a 5 percent to 15 percent excess of births in the winter and early spring among individuals destined to develop schizophrenia (Torrey and Kaufmann). These findings led to a flurry of investigations attempting to relate epidemics of specific viral agents to the births of preschizophrenic patients.

Since influenza epidemics typically occur periodically in the winter and affect a significant proportion of the population, most epidemiologic studies of prenatal infection and schizophrenia have focused on this virus. Several of these studies do suggest that prenatal influenza exposure is a risk factor for schizophrenia. The 1957 type A2 influenza .i.influenza; epidemic, the second most severe pandemic of this century, provided investigators with an excellent opportunity to examine this potential relationship. In 1988, the first such investigation, conducted in Finland, suggested a higher incidence of schizophrenia among cohorts that were in utero during the second trimester of gestation, compared to unexposed birth cohorts (Mednick and colleagues 1988). Subsequent investigations of cohorts exposed to the 1957 epidemic in Great Britain (OCallaghan and colleagues), Ireland (Cannon and others), Japan (Kunugi and others) and Australia (McGrath and others) replicated the initial finding, and all but one showed second trimester specificity for the association. Prenatal Environmental Factors Research Paper

If we want to understand child development, we need to start before birth. We have known for decades that health depends on an interaction between our genes and our environment. But we’ve also come to realize that a key part of that environment is in the womb before we’re born.

There is now considerable evidence that the mother’s emotional state during pregnancy can affect the development of her baby’s brain.

This is because of “fetal programming”, where a changing environment in the womb through different sensitive periods can alter the development of the fetus. This then goes on to affect the child in the longer term and into adulthood.

This is clearly important in physical health; if a baby grows less well than it should in the womb, he or she will be at greater risk of coronary heart disease or diabetes in later life. But there is now considerable evidence that fetal programming is also important for developmental in the brain.

Prenatal stress has been associated with the risk of a wide range of outcomes. These include both neurodevelopmental and physical problems, with the likes of anxiety, ADHD and lower cognitive development on one hand and diseases such as asthma on the other.

What kind of stress?

“Stress” is a generic term, which includes a number of different types of exposure. Many exposures, varying from mild to very severe, have been shown to affect outcomes for the child. They can include symptoms of maternal anxiety and depression, pregnancy specific anxiety, daily hassles, bereavement, life events, bad relationships and exposure to acute disasters.

Our research showed that a child’s risk of developing emotional or behavioral problems doubles from 6% to 12% if its mother is stressed, anxious or depressed. Although this means that most children will not be affected, this increased risk is of clinical significance. Prenatal Environmental Factors Research Paper

One important question is whether or not these associations between prenatal stress and altered outcomes are causal, ie directly linked, or whether the associations are due to other factors. For example, mothers who are anxious, depressed or stressed prenatally can continue to suffer these issues after the baby is born. This can also affect their parenting. Factors such as smoking, drinking alcohol and hereditary genetic defects may also play a role.

There are various ways of addressing the question of causality. Studies using animals have been conducted, where offspring were cross-fostered to eliminate parenting problems as a cause. This model also showed that prenatal stress causes behavioral alterations in offspring.

Imperial College’s Fetal and Neonatal Stress Research Group have conducted large population studies using the Avon Longitudinal Study of Parents and Children (ALSPAC) cohort from Bristol. Our research accounted for a wide range of external factors which could influence the findings, including the father’s mood, to control for genetics. The associations with child emotional and behavioral outcomes remain strong, providing good evidence for a causal link.

How stress reaches the womb

Our group wants to discover the underlying mechanism that causes this association. One possibility is that the foetus is exposed to increased amounts of the stress hormone, cortisol.

This has been shown in animal studies. And our research found that exposure to raised cortisol levels in the amniotic fluid is associated with lower cognitive function in the child later on.

We also recently proved that the function of the placenta changes in association with maternal anxiety. Essentially, we noticed a decrease in the enzyme that breaks down cortisol, potentially allowing more cortisol to pass through the placenta and affect the baby’s development.

We’re only just starting to understand these possible mechanisms. Many other systems are likely to be involved, for example the role of serotonin, a neurotransmitter that transmits signals in the brain and which is known to affect fetal neurodevelopment. Prenatal Environmental Factors Research Paper

Most anxiety, depression and emotional and physical abuse experienced by pregnant women remains undetected by health professionals. Even when the symptoms are recognize, it can be difficult to get help. To counter the harmful effects that stress has on a developing baby, we need to be more aware and provide more emotional support.

Prenatal exposure to ambient air pollution was associated with an increased risk of autism spectrum disorder, a new study finds. Pregnant women in Vancouver who were exposed to the highest level of environmental nitric oxide, an airborne, traffic-related pollutant, were more likely to give birth to children later diagnosed with autism, the researchers say.

Autism spectrum disorder, a developmental disability, is characterized by problems with communication and social interaction with accompanying repetitive behavior patterns.
Lief Pagalan, lead author of the study and a member of the faculty of health sciences at Simon Fraser University, cautions that the study, published Monday in the medical journal JAMA Pediatrics, showed only an association between prenatal exposure to nitric oxide and autism rates. It did not prove that air pollution caused autism.
Experts emphasize that the exact causes of autism remain unknown, and some say the researchers in this study did not analyze every potential risk factor. Prenatal Environmental Factors Research Paper

The intrauterine environment plays an important role in the health of the offspring. Now, experts from the University of Navarra affirm that the mother's stress, due to socio-economic or psycho-social causes, is associated with the development of pathologies related with obesity.

“The growing prevalence of obesity cannot be solely attributed to genetic factors or poor nutrition, but also to lifestyle and adverse environmental factors," as explained to SINC by Javier Campión, lead researcher of this new study. “The said environmental factors could have a bearing on epigenetic mechanisms, which are responsible for the control of genes beyond the genetic code itself".

“The growing prevalence of obesity cannot be solely attributed to genetic factors or poor nutrition, but also to lifestyle and adverse environmental factors"

For the authors, the fast pace which characterizes society produces an increase in stress rates within the population, and this rise, in parallel with the rates of obesity, makes an analysis of the interaction necessary between these two factors which do not only affect adult age groups. Prenatal Environmental Factors Research Paper

The objective of the work, which was published in the magazine ‘Stress’, was to determine the effect on adult rats of moderate chronic stress during the final week's embryonic development on the phenotypical, biochemical and hormonal changes.

To do this the researchers studied two groups of rats, with and without stress, and examined in the offspring any alterations in the expression of genes related with obesity and the metabolism of glucocorticoids in the white adipose tissue.

“The general conclusion we obtained was that an adverse situation during intrauterine development could lead to animals, due to the ingestion of a hyper-calorific diet, experiencing a greater increase in body fat and biochemical, hormonal and genetic alterations," underlined Campión.

In addition the authors insisted that these changes at adult age induced by the ingestion of a diet rich in fat and sugars provoked obesity and other associated conditions, such as insulin resistance, the result of which is the development of type-2 diabetes.

Pregnancy in the 21st Century

“These days many women continue with their hectic lives during pregnancy almost up to the birth, without noticing the stress they may be under," the researcher indicated.

The experts allege that stress, which during the normal life of a woman may not affect health, could be altering the development of the baby and leading to a predisposition towards the development of pathologies during adulthood, possibly due to epigenetic modification. Every year, problems relating to obesity are responsible for over 2.8 million deaths throughout the world.

“A healthy life during the pregnancy does not only consist of a good diet, with a good provision of vitamins and minerals, but also in living a quiet life, without stress," Campión concluded. Prenatal Environmental Factors Research Paper

ORDER A PLAGIARISM-FREE PAPER HEREEnvironmental Exposures and Epigenetics My field of research is children’s environmental health, and epigenetics plays a potentially very important role in determining the effects of early-life exposures on children’s health and development. So for example, we’re looking at the effects of environmental exposures, physical toxicants in the environment, common every day pollutants that we experience particularly in urban areas (air pollutants, Bisphenol A, phthalates, pesticides) at the low levels to which we’re generally exposed, and we have observed some relationships between fetal exposures (prenatal exposures) and health effects in children following a cohort of children for a number of years from in utero forward into childhood and even adolescence. So we look upon epigenetics as a potentially very important in mechanism in mediating those effects and in linking, helping us to link exposures to the clinical outcomes that we’re measuring, and in doing so, elucidate the mechanisms by which this damage is incurring, which we hope very much will be useful in prevention in designing effective interventions and also in monitoring the efficacy of those interventions. We’re specifically hypothesizing that prenatal exposure to environmental contaminants polycyclic aromatic hydrocarbons from fossil fuel burning, other combustion sources, secondhand tobacco smoke, pesticides used for control of indoor pests in urban areas, and what are called “endocrine-disrupting” chemicals (Bisphenol A and phthalates) that they are having an effect. “We theorize that we will be able to draw better links between those early exposures and the outcomes by understanding and measuring the epigenetic changes…” When the fetus is exposed through the mother’s environmental exposure, that they are having an effect on children’s neurodevelopment, neurobehavior particularly, on asthma risk, and obesity and metabolic disorders, and further, that they may be increasing the risk of intermediate damage associated with cancer. So we further theorized that in addition to genotoxic pathways that can be important for some of these chemical exposures, pollutant exposures, that epigenetics may be involved. And we’re studying that both within our cohorts of mothers and newborns, who are enrolled during the pregnancy period and then followed for many years into adolescence. Our oldest children are now approaching the age of 12 and 13. We theorize that we will be able to draw better links between those early exposures and the outcomes by understanding and measuring the epigenetic changes both that we determine in the cord blood at birth, looking also at placental tissue and then further following and analyzing the samples from those children at older ages. So we further theorize that the prenatal period would be a window of exquisite susceptibility to these exposures. So those are our hypotheses. Prenatal Environmental Factors Research Paper We’re not leaving out, however, the broader context, the social context in which individuals are living, to which they’re reacting on a daily basis. So we are looking at psycho-social stressors, also genetic susceptibility because we think there’s important interaction between genetic susceptibility and other environmental factors and nutritional factors. So our studies are attempting to capture those things as best we can and to look at the relationships among them. I think that through more understanding of the pathways that are involved in the effects that are observed in relation to early-life exposures, prenatal and early postnatal exposures, that through that understanding we can craft really effective and targeted interventions. Those would include behavioral interventions, educational programs for example, nutritional interventions and people are talking about pharmacological interventions as well. My area focusing on preventable environmental exposures in my area we tend to think of policy changes that can dramatically affect the environment of a population and actually dealing especially with involuntary exposures that are problematic such as, for example, air pollution. So we think in terms of how scientific data can inform policies, regulatory and other kinds of policies to address those environmental threats. I mentioned exploring. Really the word is “exploring” the interactions between the environmental exposures, the physical toxicants that we’re interested in and the other factors: genetic susceptibility, nutritional susceptibility, psycho-social stressors, all of which can worsen (exacerbate) the effect of the physical toxicants. Those studies because our cohorts are fairly limited in size we enrolled about 740 women in pregnancy and are following them and their children. Those are fairly limited. We consider them to be exploratory, but it’s important to attempt to assess those at this point and then hopefully we’ll be able to do larger studies in the future. Prenatal Environmental Factors Research Paper

Radiation exposure to a fetus

Most of the ways a pregnant woman may be exposed to radiation, such as from a diagnostic medical exam or an occupational exposure within regulatory limits, are not likely to cause health effects for a fetus. However, accidental or intentional exposure above regulatory limits may be cause for concern.

Although radiation doses to a fetus tend to be lower than the dose to the mother, due to protection from the uterus and surrounding tissues, the human embryo and fetus are sensitive to ionizing radiation at doses greater than 0.1 gray (Gy). Depending on the stage of fetal development, the health consequences of exposure at doses greater than 0.5 Gy can be severe, even if such a dose is too low to cause an immediate effect for the mother. The health consequences can include growth restriction, malformations, impaired brain function, and cancer.

Estimating the Radiation Dose to the Embryo or Fetus

Health effects to a fetus from radiation exposure depend largely on the radiation dose. Estimating the radiation dose to the fetus requires consideration of all sources external and internal to the mother’s body, including the following:

  • Dose from an external source of radiation to the mother’s abdomen.
  • Dose from inhaling or ingesting a radioactive substance that enters the bloodstream and that may through the placenta.
  • Dose from radioactive substances that may concentrate in maternal tissues surrounding the uterus, such as the bladder, and that could irradiate the fetus. Prenatal Environmental Factors Research Paper

Most radioactive substances that reach the mother’s blood can be detected in the fetus’ blood. The concentration of the substance depends on its specific properties and the stage of fetal development. A few substances needed for fetal growth and development (such as iodine) can concentrate more in the fetus than in corresponding maternal tissue.

Consideration of the dose to specific fetal organs is important for substances that can localize in specific organs and tissues in the fetus, such as iodine-131 or iodine-123 in the thyroid, iron-59 in the liver, gallium-67 in the spleen, and strontium-90 and yttrium-90 in the skeleton.

Radiation experts can assist in estimating the radiation dose to the embryo or fetus

Hospital medical physicists and health physicists are good resources for expertise in estimating the radiation dose to the fetus. In addition to the hospital or clinic’s specialized staff, physicians may access resources from or contact the following organizations for assistance in estimating fetal radiation dose.Prenatal Environmental Factors Research Paper