Embryo Project Encyclopedia

In 2006, the United States Food and Drug Administration, or FDA, published the “Requirements on Content and Format of Labeling for Human Prescription Drug and Biological Products,” also called the Physician Labeling Rule, to improve the safety and efficacy of prescription drugs and drug products. Within the Physician Labeling Rule, the FDA includes a section titled “Use in Specific Populations” or Section 8, which refers to drugs used by pregnant women, lactating women, and people of reproductive capacity. The FDA stated that the purpose of the Physician Labeling Rule was to make drug labels easier for physicians to understand and use when prescribing drugs to pregnant women. With the Physician Labeling Rule, the FDA improved patient-physician communication and the safety of drug use during pregnancy.

In 2014, the United States Food and Drug Administration published the Pregnancy and Lactation Labeling Rule to amend previous guidelines for the prescription of drugs for pregnant and lactating women. The 2014 Pregnancy and Lactation Labeling Rule was intended to increase the safety and efficacy of prescription drugs by making drug labels easier for physicians to understand and utilize. The Pregnancy and Lactation Labeling Rule restructured drug labels and required that they include narratives describing drug-associated risks to women and fetuses, rather than using complicated letter categories. The Pregnancy and Lactation Labeling Rule changed the framework for drug labeling, making it easier for doctors to prescribe safe and effective drugs to pregnant women, lactating women, and people of reproductive capacity.

Congenital rubella syndrome (CRS) can occur in children whose mothers contracted the rubella virus, sometimes called German measles, during pregnancy. Depending on the gestational period when the mother contracts rubella, an infant born with CRS may be unaffected by the virus or it may have severe developmental defects. The most severe effects of the virus on fetal development occur when the mother contracts rubella between conception and the first trimester. Defects from maternal rubella in the first trimester are included in the term congenital rubella syndrome, but physicians and researchers specifically refer to those defects as rubella embryopathy. Developmental defects are less severe if the mother contracts rubella in the second trimester, and they are generally negligible if the infection occurs in the third trimester. Prenatal rubella infection can cause birth defects which include deafness, compromised vision, abnormal heart development, and damage to the central nervous system which can lead to compromised cognition and learning disabilities.

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. Teratogens are classified into four types: physical agents, metabolic conditions, infection, and finally, drugs and chemicals.