Risk of preterm birth in primiparous women with exposure to antidepressant medication before pregnancy and/or during pregnancy - impact of body mass index.

INTRODUCTION

Preterm birth is a major cause of infant mortality. It is unknown whether body mass index (BMI) influences the risk of preterm birth in women, who prenatally use antidepressants.

MATERIALS AND METHODS

The study cohort (N = 6920) consists of all primiparous European born women without previously diagnosed diabetes from the city of Vantaa, Finland, who delivered a singleton child between 2009 and 2015. Data on births, pre-pregnancy BMI and purchases of antidepressants from 12 months before conception until delivery were obtained from Finnish National Registers.

RESULTS

Of the primiparous women, 9.9% used antidepressants. The overall prevalence of preterm birth was 5.2%. In women with a pre-pregnancy BMI <18.5 kg/m, the Odds Ratio (OR) for preterm birth among antidepressant users compared with those who were non-users was 1.91 (95% confidence intervals [CI] 0.40 to 9.15, adjusted for age, smoking, education, use of fertility treatments and number of previous pregnancies) while in women with a pre-pregnancy BMI ≥30 kg/m, the OR was 0.53 (95% CI 0.21-1.36), respectively.

DISCUSSION

Primiparous women using antidepressants, who were underweight before conception should be closely monitored and provided tailored care in a maternity clinic to minimize the risk of preterm birth. Key messages In primiparous women, one in ten used antidepressant medications before pregnancy and/or during pregnancy. In primiparous women, the prevalence of preterm birth was 5%. Underweight primiparous women using antidepressants should be closely monitored and provided tailored care in a maternity clinic.