Prenatal exposure to anxiolytics and hypnotics and language competence at 3 years of age.

Purpose: The aim of the study was to examine if there was an association between use of anxiolytics and hypnotics in pregnancy and language competence in the offspring at age 3 years.
Methods: The Norwegian Mother and Child Cohort Study (MoBa) is a prospective pregnancy cohort where the mothers were asked to report on their medication use at pregnancy week 17-18, 30, and at 6 months postpartum. A woman was defined as a user of anxiolytics and hypnotics during pregnancy if she had reported use of benzodiazepines or benzodiazepine-related drugs during pregnancy. Children's language competence was measured at age three by maternal report on a validated language grammar scale. We used ordinal logistic regression with estimated standard errors allowing for clustering of multiple pregnancies.
Results: Forty-five thousand and two hundred sixty-six women with 51,748 pregnancies were included in the study. The women reported use of anxiolytics and/or hypnotics in 395 pregnancies (0.8 %). The odds ratios of being in a group with lower language competence were 1.2 (0.9-1.5) and 1.7 (1.0-2.8) for short-term and long-term anxiolytics and hypnotics use, respectively. When adjusting for SSRI use during pregnancy, the odds ratios were 1.1 (0.83-1.41) and 1.4 (0.84-2.33), respectively. Children whose mothers took no anxiolytics and hypnotics during or before pregnancy were reference group.
Conclusion: The results refute any strong association between prenatal use of anxiolytics and hypnotics and lower language competence in the offspring at age 3 years.