According to research published in the Archives of Pediatrics and Adolescent Medicine, in utero exposure to selective serotonin reuptake inhibitors (SSRIs) may increase the risk of early delivery, low Apgar score at 5 minutes, and admission to a neonatal intensive care unit.

The prospective cohort study involved pregnant women receiving prenatal care in a Danish hospital between 1989 and 2006. The primary outcome measures of gestational age, birth weight, head circumference, 5-minute Apgar score, and admission to the neonatal intensive care unit were assessed for those who had been exposed to SSRIs during pregnancy, and controls (no SSRI exposure). The researchers evaluated data from 329 pregnant women who reported treatment with SSRIs, 4902 women who were not treated with SSRIs but had a history of psychiatric illness, and 51,770 who reported no history of psychiatric illness. 
 

The following results were reported:
• Gestational age was 5 days (95% confidence interval [CI], –6 to –3) shorter and the odds ratio (OR) for preterm birth was 2.0 (95% CI, 1.3-3.2) in the women exposed to SSRIs compared with women with no history of psychiatric illness. Compared to women with a psychiatric history, gestational age was 3.8 days shorter in women with SSRI exposure during pregnancy (−5.6 to −2.0).
• In utero–exposed newborns had increased risk of admission to the neonatal intensive care unit (OR, 2.4; 1.7-3.4) and of 5-minute Apgar scores of less than 8 (OR, 4.4; 2.6-7.6) compared with those not exposed.
• Head circumference and birth weight did not differ between infants in the exposed and unexposed groups. The results were similar when compared with infants of women with a psychiatric history.

The researchers conclude that the increased risk of preterm delivery, the low 5-minute Apgar score, and neonatal intensive care unit admission, was not explained by lower Apgar scores or gestational age. Therefore, this study justifies increased awareness to the possible effects of intrauterine exposure to antidepressants.