Examination of Infant Sex Differences in Neonatal Opioid Withdrawal Syndrome Severity After In-Utero Buprenorphine Exposure in the MOMS Clinical Trial

Objectives: Neonatal opioid withdrawal syndrome (NOWS) severity is influenced by several clinical factors; however, the association with infant sex is poorly understood. We examined the association between infant sex and NOWS severity in a cohort of buprenorphine-exposed infants. Methods: This was a secondary analysis of the MOMS clinical trial (NCT03918850). Regression models evaluated the association between infant sex and NOWS severity measures, including (1) receipt of any pharmacologic treatment, (2) opioid treatment days, (3) adjunctive medication treatment, (4) length of hospital stay (LOS), and (5) LOS related to NOWS. Results: There were 135 infants (67 male, 68 female). There were no significant differences in demographics or medical comorbidities by infant sex. Methamphetamine and phencyclidine exposures were positively associated with receipt of any pharmacologic treatment, and phencyclidine with longer LOS. Breastfeeding was associated with decreased receipt of any pharmacologic treatment and shorter total LOS, and preterm delivery and NICU admission with longer total LOS. In final regression models, NOWS severity did not differ by infant sex. Conclusions: Infant sex was not statistically associated with NOWS severity measures within this buprenorphine-exposed cohort. Meta-analyses are needed to better understand the relationship between infant sex and NOWS.