Spellacy N, Buhi WC, Bradley B, et al: Maternal, fetal, amniotic fluid levels of glucose, insulin, and growth hormone. Obstet GynecoIo41:323, 1973 Weiss PA, Hofmann H, Winter R, et al: Amniotic luid glucose values in nor mal and abnormal pregnancies. Obstet Gynecol 65:333, 1985
Wiegand SL, Beamon q, Chescheir NC, et al: Idiopathic polyhydramnios: severity and perinatal morbidity. Amo] Perinatol 33(7):658, 2016
Wood SL, Newton ]M, Wang L, et al: Borderline amniotic luid index and its relation to fetal intolerance of labor: a 2-center retrospective cohort study. ] Ultrasound Med 33(4):705, 2014
CHAPTER 12 Teratology, Teratogens, and Fetotoxic Agents
TERATOLOGY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235
CRITERIA FOR DETERMINING TERATOGENICITY .e... 235
COUNSELING FOR MEDICATION EXPOSURE . ..e...e. 238
KNOWN AND SUSPECTED TERATOGENS .e.. .e. 239
Al inectious diseases have a tendency to bring about death of the chid and its subsequent expulsion from the uterus. The atal result is usualy due to the transmission of toxins, and occasionaly the speciic micro-organisms from the mother to the chil. Poisoning with phosphorus, lead, iluminating gas, and other substances may lead to similar results.
-J. Whitridge Williams (1903)
Other than referring to fetal deformities that might impede vaginal delivery, little is written in the first edition of this book regarding teratogens and fetal malformations. his is despite the fact that birth defects are common, and 2 to 3 percent of all newborns have a major congenital abnormality detectable at birth (Cragan, 2009; Dolk, 2010). There are undoubtedly medications that pose significant risk to the developing embryo or fetus (Table 12-1). However, 80 percent of birth defects do not have an obvious etiology, and of those with an identified cause, nearly 95 percent' of cases have chromosomal or genetic origins (Feldkamp, 2017). The Food and Drug Administration (FDA) (2005) estimates that less than 1 percent of all birth defects are caused by medications. Their remarkably small contribution to congenital abnormalities is shown in Figure
That said, signiicant concern surrounds medication use in pregnancy. This is because so many pregnant women are prescribed medications and because safety data are often lacking. Investigators from the National Birth Defects Prevention Study found that women take an average of two to three medications per pregnancy and that 70 percent use medication in the first trimester (Mitchell, 2011). And, in one review of medications approved by the FDA between 2000 and 2010, the Teratogen Information System (TERIS) advisory board deemed the
TABLE 12-1. Selected Teratogens and Fetotoxic Agents