Embryo Project Encyclopedia

During the mid-twentieth century, Virginia Apgar worked as an obstetrical anesthesiologist and gave drugs to women that reduced their pain during childbirth in the US. In 1953, Apgar created a scoring system, called the Apgar score, that uses five measurements, including heart rate and breathing rate. The Apgar score evaluates newborn infants and determines who needs immediate medical attention. Apgar's work helped decrease infant mortality rates. As of 2020, hospitals around the world use the Apgar score.

Isotretinoin is a molecule and a byproduct (metabolite) of vitamin A, and in greater than normal amounts in pregnant women, it can cause fetal abnormalities including cleft lips, ear and eye defects, and mental retardation. Isotretinoin is commonly called by its trade name Accutane, and it's a chemical compound derived from vitamin A, or retinoic acid. Doctors prescribe isotretinoin to treat severe acne. For pregnant women, too much vitamin A or isotretinoin can also cause greater than normal rates of stillbirths and fetal disintegrations after the ninth week of gestation. Women who use isotretinoin during the first trimester of their pregnancies, even in small amounts, risk defects to their fetuses such as external ear malformations, cleft palates, undersized jaws (micrognathia), a variety of heart defects, buildups of fluids inside the skulls that leads to brain swelling (hydrocephalus), small heads and brains (microcephaly), and mental retardation.

Josef Warkany studied the environmental causes of birth defects in the United States in the twentieth century. Warkany was one of the first researchers to show that factors in the environment could cause birth defects, and he helped to develop guidelines for the field of teratology, the study of birth defects. Prior to Warkany’s work, scientists struggled to explain if or how environmental agents could cause birth defects. Warkany demonstrated that a deficiency or excess of vitamin A in maternal nutrition could cause birth defects. He also established that mercury in teething powders increased infant mortality rates. Warkany showed how substances outside the human body could adversely affect conception, growth, and development of the human fetus in utero.

In its 1993 decision Daubert v. Merrell Dow Pharmaceuticals, Inc., the US Supreme Court established the Daubert Standard for evaluating the admissibility of scientific knowledge as evidence in US federal courts. When it began in trial court, the case addressed whether or not Bendectin, an anti-nausea medication taken during pregnancy, caused birth defects. However, after the trial court dismissed the case for lack of admissible evidence, Daubert v. Merrell Dow Pharmaceuticals, Inc. advanced through appeals courts to the US Supreme Court, where the Justices defined the criteria by which scientific knowledge, which for them included a least theories based on evidence, expert testimony from scientists, and scientific techniques, could be introduced and used in court cases as evidence. The Daubert Standard states that the judge of a case is responsible for determining what claims are admissible as scientific knowledge and as evidence in the case. The admissibility should be determined by the falsifiability of the claims, by whether or not they had passed peer reviewed, by the general scientific acceptance of the claims, and for techniques, by their error rates of the techniques. Daubert v. Merrell Dow Pharmaceuticals, Inc. set a landmark precedent in the US judicial system and influenced most subsequent legal cases that appealed to science to establish facts in trials.

In March 1996, the National Academy of Sciences of the United States released 'Veterans and Agent Orange Update 1996: Summary and Research Highlights,' which summarized research on the health effects of Agent Orange and other herbicides used in the Vietnam War. In their 1996 report, the National Academy connects Agent Orange exposure with two health conditions: spina bifida, a birth defect that occurs when the spinal cord develops improperly, and peripheral neuropathy, a nervous system condition in which the peripheral nerves are damaged. Spina bifida was the first birth defect to linked to Agent Orange exposure. The resulting disability compensation for affected children, as a result of the conclusions in the 1996 report, marked the first time that the US Veterans Administration addressed the health outcomes of veterans' families, and not exclusively veterans themselves.

Sprayed extensively by the US military in Vietnam, Agent Orange contained a dioxin contaminant later found to be toxic to humans. Despite reports by Vietnamese citizens and Vietnam War veterans of increased rates of stillbirths and birth defects in their children, studies in the 1980s showed conflicting evidence for an association between the two. In 1996, the US National Academy of Sciences reported that there was evidence that suggested dioxin and Agent Orange exposure caused spina bifida, a birth defect in which the spinal cord develops improperly. The US Department of Veterans Affairs' subsequent provision of disability compensation for spina bifida-affected children marked the US government's first official acknowledgement of a link between Agent Orange and birth defects. By 2016, spina bifida and related neural tube defects were the only birth defects associated with Agent Orange.

Spina bifida is a birth defect that affects the spines of developing fetuses and infants, and research in the 20th century indicated that chemicals in the herbicide Agent Orange likely lead to the birth defect. People with spina bifida can have nerve damage, paralysis, and mental disabilities. During the Vietnam War in the 1960s, the US military employed Agent Orange and other herbicides to destroy enemy crops and forest cover until 1970. Though studies of the link between Agent Orange exposure and birth defects were at first inconclusive, in 1995 the US National Academy of Sciences concluded that one birth defect, spina bifida, was associated with paternal Agent Orange exposure. Spina bifida was, by the twenty-first century, the only birth defect that the US Veterans Administration connected to Agent Orange exposure.

Fortunio Liceti studied natural philosophy and medicine in Italy during the first half of the seventeenth century. Liceti wrote greater than seventy works on a wide range of topics, including the human soul, reproduction, and birth defects observed in animals and human infants. In the seventeenth century, people commonly addressed birth defects using superstition and considered them as signs of evil, possibly caused by spiritual or supernatural entities. Liceti described infants with birth defects as prodigies and monsters to be admired and studied rather than feared. Liceti’s works established monsters as a possible subject of scientific inquiry and served as models for the future study of birth defects, a field later called teratology. Liceti was one of the first scholars to attempt to systematically categorize birth defects based on their causes, including multiple causes unrelated to the supernatural.

Truman William Brophy developed a cleft palate surgical repair, later called the Brophy Operation, in the late nineteenth century US. The procedure improved facial aesthetics and speech in cleft palate patients. A cleft palate occurs during development when the palatal bones in the roof of the mouth don't completely fuse, leaving an opening, or cleft, in the upper lip and mouth. Brophy's cleft repair used compression inside and outside of the mouth to push the palatal bones into normal alignment shortly after birth. Brophy advocated surgery on newborns with cleft palates as soon as possible after birth, which met with opposition in the late nineteenth and early twentieth centuries when medical professionals did not operate on infants for non-life threatening conditions. However, Brophy's successful operations convinced many doctors to adopt his technique.

In 1984, J. David Erickson and his research team published the results of a study titled 'Vietnam Veterans' Risks for Fathering Babies with Birth Defects' that indicated that Vietnam veterans were at increased risk of fathering infants with serious congenital malformations, or birth defects. Researchers at the Centers for Disease Control (CDC) in Atlanta, Georgia, conducted the study to address Though the study's results were inconclusive, the study was one of the first to document a possible association between Vietnam War service and spina bifida, a lower back birth defect in which the spinal cord does not form properly. Later research established the links between Agent Orange exposure and various birth defects and led the US Department of Veterans Affairs to offer disability compensation for Vietnam veterans and their families who were affected by Agent Orange exposure.