Newborns born to narcotic addicts may have withdrawal symptoms 6 h to 8 days after birth. Salicylates compete with bilirubin for albumin binding sites and may produce fetal kernicterus. Large doses of aspirin may delay the onset of labor and cause premature closure of the fetal ductus arteriosus, a maternal bleeding diathesis during the intrapartum or postpartum period, or neonatal bleeding. Phenothiazines have been used during pregnancy as antiemetic and psychoactive drugs. They readily cross the placenta and, as a group, appear to pose an insignificant fetal risk.
Diazepam is the most commonly administered anxiolytic.
Although some epidemiologic studies have found an increased rate of anomalies with its use, most studies have concluded that no such association exists. When diazepam is given near the end of pregnancy, depression, irritability, tremors, and hyperreflexia in newborns have been reported. Studies of fetal exposure to meprobamate and chlordiazepoxide show no evidence of increased incidence of malformations or fetal deaths. Isolated reports note that newborns whose mothers received tricyclics just before delivery may have tachycardia, respiratory distress, and urinary retention. Cardiovascular abnormalities, including Ebstein's anomaly, were most common.