Antidepressant medication continuation during pregnancy and perinatal outcomes, including gestational weight gain, gestational diabetes, and birth weight

BACKGROUND

Every year, approximately 7–8% of pregnant women in the US (~300,000 women) use antidepressants. Use of certain antidepressants in non-pregnant populations has been associated with weight loss, whereas others have been associated with weight gain; in pregnant women, the association of antidepressant use and gestational weight gain has not been thoroughly investigated. Some studies have observed greater risk of gestational diabetes (GDM) and smaller birthweight associated with prenatal antidepressant use. However, most studies compared women using antidepressants with unexposed pregnant women from the general population, most of whom did not have depression or anxiety, likely leading to confounding by indication.

OBJECTIVE

To assess the association of antidepressant continuation in pregnancy with gestational weight gain, GDM, and infant birthweight among women using antidepressants before pregnancy.

METHODS

We conducted a retrospective cohort study of singleton live births from 2001–2014 to women enrolled in an integrated healthcare system using electronic health data and linked Washington State birth records. This included women with ≥1 antidepressant prescription, filled ≤6 months before pregnancy. Women with any antidepressant fill during pregnancy were considered “exposed” (n=1,772); those without were “unexposed” (n=1,249). We calculated mean differences and relative risks (RR) using generalized estimating equations with inverse probability of treatment weighting to account for baseline characteristics, including indicators of pre-pregnancy mental health status.

RESULTS

Women who continued versus discontinued antidepressants during pregnancy had similar risks of inadequate and excessive gestational weight gain (RR 0.95, 95% confidence interval [CI] 0.80–1.13 and RR 1.06, 95% CI 0.98–1.14, respectively). Continuing antidepressant use in pregnancy was not associated with greater risk of GDM (RR: 1.10, 95% CI: 0.84–1.44), with the potential exception of venlafaxine continuation (RR 1.52, 95% CI 0.87–2.68). We observed greater risk of small for gestational age associated with antidepressant continuation among female infants (RR: 1.65, 95% CI: 1.09-2.50), but not among male infants (RR: 0.86, 95% CI: 0.58-1.27). After restricting continuers to women with fills in all three trimesters, we observed a decreased risk of large for gestational age (RR: 0.68, 95% CI: 0.52–0.91) and macrosomia (RR: 0.49, 95% CI: 0.25–0.99) among continuers compared with discontinuers. There was a suggestion of lower risk of large for gestational age among female infants (RR: 0.74, 95% CI: 0.55-1.00) but not among male infants (RR: 0.91, 95% CI: 0.66-1.26).

CONCLUSIONS

Our study indicates that women and their providers do not need to be concerned about antidepressant continuation causing dramatic increases in risk of the outcomes studied here. We observed evidence of moderately increased risk of GDM and small for gestational age specific to some subgroups of continuers, but additional research is needed to confirm these findings.