"To examine the extent and clinical sequelae of fetal exposure to zolpidem, a commonly prescribed hypnotic agent. Pregnant women with psychiatric illness participating in a study of psychotropic pharmacokinetics were included," scientists in the United States report (see also Obstetrics).

"Zolpidem concentrations were analyzed in maternal and umbilical cord plasma collected at delivery. were compared between the zolpidem-exposed group and a 1:1 matched comparator group. Forty-five women taking zolpidem during pregnancy were studied. Rates of preterm delivery and low birth weight were 26.7% and 15.6% respectively in the zolpidem-exposed group versus 13.3% and 4.4% in the matched comparator group, but no significant differences were found. The ratio of umbilical cord to maternal plasma zolpidem concentrations in 6 pairs ranged from 0.48 to 2.75. Zolpidem crosses the human placenta and rapidly clears the fetal circulation," wrote S. Juric and colleagues, Emory University, Medical Department.

The researchers concluded: "Pregnant women with psychiatric illness treated with zolpidem may have less optimal obstetrical outcome, though it is unclear if this was related to the medication."

Juric and colleagues published their study in Archives of Womens Mental Health (Zolpidem (AmbienA®) in pregnancy: placental passage and outcome. Archives of Womens Mental Health, 2009;12(6):441-446).

For additional information, contact Z.N. Stowe, Emory University, School Medical, Dept. of Psychiatry, 1365 Clifton Rd. NE, Suite B6100, Atlanta, GA 30322, USA.

The publisher's contact information for the journal Archives of Womens Mental Health is: Springer Wien, Sachsenplatz 4-6, PO Box 89, A-1201 Wien, Austria.