Embryo Project Encyclopedia Articles

From 1993 to 1995 researchers led by Robert J. Berry from the US Centers for Disease Control headquartered in Atlanta, Georgia, and Zhu Li from Beijing Medical University in Beijing, China, conducted a collaborative study in China on the prevention of neural tube defects or NTDs using folic acid supplements. NTDs are birth defects in which openings in the spinal cord or the brain that occur during early development remain after birth. Neural-tube formation occurs in early pregnancy, often before a woman knows she is pregnant and therefore before she has begun taking prenatal vitamins. The researchers presented their findings in the article “Prevention of the Neural Tube Defects with Folic Acid in China” published in 1999 in The New England Journal of Medicine. The researchers from The China-US study found that women who took folic acid in the periconceptional period, or the time before conception through the first twenty-eight days after conception, reduced the occurrence of NTDs.

In April 1994, Elizabeth Raymond, Sven Cnattingius, and John Kiely published “Effects of Maternal Age, Parity, and Smoking on the Risk of Stillbirth” in the British Journal of Obstetrics and Gynecology, now known as BJOG: An International Journal of Obstetrics and Gynecology. The article examines how advanced maternal age, defined as delivery at thirty-five years old or older, cigarette smoking, and nulliparity, or the state of never having given birth, can negatively impact pregnancy. At the time of publication, according to Raymond and colleagues, stillbirths comprised over half of all perinatal, or close to birth, deaths and more than one-third of total fetal and infant deaths in Europe and North America. In the article, Raymond and her coauthors demonstrate how certain risk factors may increase the risk of stillbirth at different stages of pregnancy, which helped set a foundation for future research in interventions to prevent stillbirth.

Fetus in fetu is a rare variety of parasitic twins , where the developmentally abnormal parasitic twin is completely encapsulated within the torso of the otherwise normally developed host twin. In the late eighteenth century, German anatomist Johann Friedrich Meckel was the first to described fetus in fetu, which translates to “fetus within fetus.” Fetus in fetu is thought to result from the unequal division of the totipotent inner cell mass , the mass of cells that is the ancestral precursor to all cells in the body. The unequal division is thought to occur during the formation of the blastocyst, which can also result in parasitic and conjoined twins . Fetus in fetu represents a developmental anomaly that has prompted developmental biologists to further examine the mechanisms for how twins arise.

In 1904, physician William Henry Walling published Sexology, a family medicine reference book. In his book, Walling proposed that his guidance would help people who were married or single and young or old, as well as anyone who wanted to conform to, what he claims are, gender expectations. Sexology discusses issues such as masturbation, abortion, pregnancy, labor, and marriage. Despite Walling’s limited scientific explanations and evidence for his medical claims, the Puritan Publishing Company printed and distributed the book, which received many positive reviews and endorsements from other physicians, college presidents, politicians, and religious leaders. However, in the twenty-first century, people may consider many of Walling’s claims to be sexist and oppressive toward women. Sexology provides readers with examples of historical medical misconceptions of male and female anatomy and provides context for the logic of reproductive medicine at the turn of the twentieth century.

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.

Jesse Bennett, sometimes spelled Bennet, practiced medicine in the US during the late eighteenth century and performed one of the first successful cesarean operations, later called cesarean sections, in 1794. Following complications during his wife’s childbirth, Bennett made an incision through her lower abdomen and uterus to deliver their infant. Bennett’s biographers report that his operation was the first cesarean section where both the pregnant woman and the infant survived. Previously, physicians used cesarean sections to save the fetus from a pregnant woman who had already died during childbirth. Bennett successfully performed a cesarean section, a procedure used worldwide in the twenty-first century when a vaginal delivery is not possible or would pose a risk to the woman or fetus.

In 1999, the Inter-agency Working Group on Reproductive Health in Crises, hereafter the IAWG, wrote the Minimum Initial Services Package, hereafter MISP, which is the second chapter in Reproductive Health in Refugee Situations: An Inter-agency Field Manual. The IAWG wrote MISP for governments and agencies, who respond to humanitarian crises, as a guide for the provision of reproductive health services at the beginning of a humanitarian crises. The goal of MISP was to outline the services that people in humanitarian crises are to receive to minimize injury and death from complications related to reproductive health, prevent and manage the consequences of sexual violence, and reduce the transmission of sexually transmitted infections, or STIs. MISP recognizes that reproductive health is a human right and applies to people in humanitarian crises, providing specific details for governments and agencies to follow and mitigate the adverse effects of reproductive health issues in vulnerable populations.

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.

The concept Fetal Alcohol Syndrome (FAS) refers to a set of birth defects that occur in children born to mothers who abused alcohol during pregnancy. The alcohol-induced defects include pre- and post-natal growth deficiencies, minor facial abnormalities, and damage to the developing central nervous system (CNS). FAS is the most serious condition physicians group under the heading of Fetal Alcohol Spectrum Disorders, which also includes Alcohol-Related Birth Defects, like alcohol-induced congenital cardiac defects that are unrelated to a diagnosis of FAS, and Alcohol-Related Neurodevelopmental Disorders, which occur in the absence of any facial birth defects or growth delays. The severity of birth defects associated with FAS can vary depending on the intensity, duration, and frequency of exposure to alcohol during gestation. In addition to these dose-related concerns, maternal factors such as the mother's genetics or how quickly she metabolizes alcohol, and the timing of exposure during prenatal development also impact alcohol-induced abnormalities. As birth defects and anomalies can arise when pregnant women consume alcohol, alcohol is a teratogen, an environmental agent that negatively impacts the course of normal embryonic or fetal development.

In Stenberg v. Carhart, the US Supreme Court ruled on 28 June 2000 that a Nebraska law banning partial birth abortions was unconstitutional. Though the US Supreme Court case Roe v. Wade in 1973 had set a precedent that constitutionally protected abortions, some states established limitations on certain types of abortion procedures. When NebraskaÕs state government criminalized partial birth abortions, physician LeRoy Carhart challenged the constitutionality of the case. Don Stenberg, an Attorney General located in Lincoln, Nebraska, represented the state of Nebraska. Stenberg determined that states could not create undue burden on womenÕs right to terminate their pregnancies, and that specific restrictions on abortion procedures must include an exception to protect a womanÕs health and life.