Risk Summary 

There are no adequate and well-controlled studies in pregnant women. In animal reproduction studies, fetal deaths and reduced pup survival were noted after intravenous administration of etomidate to pregnant rats at doses 0.17 times the human induction dose of 0.3 mg/kg. Reduced pup survival was noted after intravenous administration of etomidate to pregnant rabbits at 1.6 times the human induction dose. Published studies in pregnant primates demonstrate that the administration of anesthetic and sedation drugs that block NMDA receptors and/or potentiate GABA activity during the period of peak brain development increases neuronal apoptosis in the developing brain of the offspring when used for longer than 3 hours. There are no data on pregnancy exposures in primates corresponding to periods prior to the third trimester in humans. [See Data] 

The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively.

Data 

Animal Data 

No malformations or adverse fetal effects were noted in a study in which pregnant rats were intravenously administered 0.31, 1.25, or 5 mg/kg/day etomidate (0.17, 0.68, or 2.7 times the human induction dose of 0.3 mg/kg based on body surface area) during organogenesis (Gestation Days 6-15). 

Reduced pup survival was noted in all doses tested in a study in which pregnant rabbits were intravenously administered 1.5 or 4.5 mg/kg/day etomidate (1.6 or 4.9 times the human induction dose of 0.3 mg/kg based on body surface area) during organogenesis (Gestation Day 6-18). These doses also produced maternal toxicity (increased mortality). 

Increased still born fetuses and decreased pup survival was noted at all doses tested in a study where pregnant rats were intravenously administered 0.31, 1.25, or 5 mg/ kg/day etomidate (0.17, 0.68, or 2.7 times the human induction dose of 0.3 mg/kg based on body surface area) during gestation and throughout lactation (Gestation Day 16 through Lactation Day 21). These doses also produced maternal toxicity (decreased food consumption and increased mortality). In this study, offspring were not evaluated for sexual maturation, neurobehavioral function including learning and memory, or reproductive function. 

In a published study in primates, administration of an anesthetic dose of ketamine for 24 hours on Gestation Day 122 increased neuronal apoptosis in the developing brain of the fetus. In other published studies, administration of either isoflurane or propofol for 5 hours on Gestation Day 120 resulted in increased neuronal and oligodendrocyte apoptosis in the developing brain of the offspring. With respect to brain development, this time period corresponds to the third trimester of gestation in the human. The clinical significance of these findings is not clear; however, studies in juvenile animals suggest neuroapoptosis correlates with long-term cognitive deficits (See WARNINGS/ Pediatric Neurotoxicity, PRECAUTIONS/Pregnancy, ANIMAL TOXICOLOGY AND/OR PHARMACOLOGY).