Fetal Physiology

Form
Interference with development in the first trimester of pregnancy would tend to cause problems with human form, or appearance, since this is a time when basic structures are being established during fetal life. Environmental exposures, including certain medications, can have an influence on genes and cell receptors involved with form, which could result in structural problems as the fetus begins to develop. An example of this is the prescription drug Thalidomide, which was used in the 1960’s to treat morning sickness in pregnant women in the first trimester of pregnancy. Use of this drug was discontinued during pregnancy because children born to women who had been given the drug had severe limb malformations.