Question

What is a teratogen? How can a teratogen and chronic stress impact a developing fetus? Give substance and conclude with one potential mental and physical health outcomes. Tie in endocrinology in the response.

Answer 1

• Teratogens are substances that may produce physical or functional defects in the human embryo or fetus after the pregnant woman is exposed to the substance. Alcohol and cocaine are examples of such substances. Exposure to the teratogen affects the fetus or embryo in a variety of ways, such as the duration of exposure, the amount of teratogenic substance, and the stage of development the embryo or fetus is in during the exposure.
• Teratogens may affect the embryo or fetus in a number of ways, causing physical malformations, problems in the behavioral or emotional development of the child, and decreased intellectual quotient (IQ) in the child. Additionally, teratogens may also affect pregnancies and cause complications such as preterm labors, spontaneous abortions, or miscarriages.
• Metabolic conditions affecting pregnant females such as malnutrition, diabetes, and thyroid disorders are a second category of teratogens. Metabolic conditions are abnormalities in the chemical process of producing energy from food, and thereby affect the development and function of the body. If a pregnant woman is malnourished, then her fetus likely lacks the nutrients essential for its development. In the case of diabetes, low blood sugar, or hypoglycemia, may cause fetal malformations.
• Hypoglycemia interferes with some proteins in the developing fetal heart by increasing the expression of proteins which are regulated by glucose. Excessive blood sugar, also seen with diabetes, may cause neural tube defects, or birth defects of the brain and spinal cord, and may also induce the release of free radicals, or damaged cells that are missing an essential molecule, which disrupt fetal development.
• Alcohol, which is a teratogen, can cause Fetal Alcohol Syndrome (FAS) in children born to women who drank too much alcohol while pregnant. FAS can cause defects such as minor facial abnormalities and damage to the brain, which consequently leads to learning, behavioral, and cognitive abnormalities.
• Stress hormones in the mother’s body do reach the baby. When a pregnant woman is chronically stressed or experiences extreme stress, the baby may be exposed to unhealthy levels of stress hormones, which can impact the baby’s brain development. Chronic or extreme maternal stress may also cause changes in the blood flow to the baby, making it difficult to carry oxygen and other important nutrients to the baby’s developing organs. In addition, chronically or severely stressed mothers may feel overwhelmed and fatigued which might impact their diet and sleep habits and consistency of prenatal care.
• Stress experienced by a woman during pregnancy may affect her unborn baby as early as 17 weeks after conception, with potentially harmful effects on brain and development, according to new research. The study is the first to show that unborn babies are exposed to their mother's stress hormones at such an early stage in pregnancy.
• The findings, published in the journal Clinical Endocrinology, come after separate research on animals showed that high levels of stress in a mother during pregnancy could affect brain function and behaviour in her offspring, and other evidence suggesting that maternal stress in humans can affect the developing child, including lowering its IQ.
• A number of drugs have been developed to mimic or inhibit the actions of hormones, including diethylstilbestrol (DES), oral contraceptives and hormones used in fertility treatment. These medications and other endocrine disrupting chemicals (EDCs), such as bisphenol A and phthalates, may interfere with the physiologic functions of endogenous hormones by affecting their release, binding or metabolism.
• The actions of EDCs in utero have been of concern because of their possible impact on the developing reproductive systems, especially since treatment of pregnant women with the synthetic estrogen DES led to an increased risk of vaginal adenocarcinoma in their daughters.
• Several drugs disturb the folate metabolism and may have a teratogenic effect through inhibition of the folate methylation cycle.Some anti-epileptic drugs, e.g. carbamazepine and valproic acid, are generally known to increase the risk of folate-sensitive birth defects, such as neural tube defects, orofacial clefts and limb defects.