WASHINGTON – Even though the sleeping aid zolpidem does cross the placenta, use of the drug during pregnancy does not appear to significantly affect outcomes, a study of 45 women shows.
The study, presented as a poster at the annual meeting of the American Psychiatric Association, included pregnant women who were enrolled in a prospective study of the pharmacokinetics of psychotropic drugs during pregnancy and who were treated with zolpidem (Ambien) during pregnancy. Maternal diagnoses were determined using the Structured Clinical Interview for DSM-IV (SCID). Maternal and cord blood were obtained at delivery when possible.
The placental passage rate was calculated as the ratio of medication concentration in the umbilical cord plasma to that in maternal plasma. When umbilical cord concentrations were below the limit of detection (less than 4.0 ng/mL), this value was used for data analysis. This approach was thought to be conservative, erring toward overestimation of fetal exposure to zolpidem. When both maternal and umbilical plasma concentrations were less than the detection limit, the pair was excluded from the analysis.
Obstetrical and neonatal outcomes among women who had given birth to a live infant after taking zolpidem during pregnancy were compared with outcomes among a group of 45 women who were matched for age, race, level of education, SCID diagnosis, and pregnancy exposure to the same classes of psychotropics.
For women who took zolpidem during pregnancy, exposure by trimester included 38% in the first trimester, 56% in the second trimester, and 38% in the third trimester. The average zolpidem exposure during pregnancy was 14 weeks, and the average dose was 9 mg.
No statistically significant differences were found between the two groups in terms of obstetrical and neonatal outcomes. However, a trend toward preterm delivery and low-birth-weight infants was seen among women on zolpidem during pregnancy. “It is unclear if these outcomes were driven by zolpidem exposure and/or sleep disturbance or other pharmacological intervention in pregnancy,” wrote Sandra Juric and her colleagues at Emory University's Women's Mental Health Program in Atlanta. Ms. Juric reported no conflicts of interest.