Implications of perinatal buprenorphine exposure on infant head circumference at birth

Objective: To determine the potential impact of prenatal buprenorphine exposure on head circumference at birth and analyze whether head circumference may be related to maternal buprenorphine dose at delivery, delayed maternal entry into buprenorphine treatment or exposure to a variety of other medications and substances.Methods: A retrospective cohort study was performed of 137 full-term infants exposed to buprenorphine during pregnancy from January 2013 to December 2017. Pearson's correlation was calculated to investigate the potential relationship between head circumference and maternal dose of buprenorphine at delivery. t-tests were conducted to analyze head circumference in relationship to dichotomous variables.Results: Head circumference in infants exposed to buprenorphine during pregnancy was not significantly different from national norms for either male infants (95% CI 28.2-33.5 cm, norm 31.5 cm, and 28.5-34.9 cm, norm 33.1 cm, for the 3rd and 10th percentile, respectively) or female infants (95% CI 28.7-32.8 cm, norm 31.9 cm, and 29.1-34.3, norm 32.8 cm for the 3rd and 10th percentile, respectively). Head circumference was not associated with delayed maternal entry into buprenorphine treatment (t = -1.0715, p = .287) or exposure to psychotropic medications during pregnancy (t = 0.4194, p = .677). There was no relationship between infant head circumference and maternal buprenorphine dose at delivery (r = 0.004, p = .967). Head circumference was not associated with maternal smoking (t = 0.003, p = .998) or exposure to marijuana (t = 0.7277, p = .468), illicit opioids (t = -0.6701, p = .504), illicit amphetamines (t = -0.4062, p = .687) or illicit benzodiazepines (t = -0.6288, p = .535) during pregnancy.Conclusions: Exposure to buprenorphine prenatally does not appear to be associated with reduced head circumference at birth. Head circumference at birth also does not appear related to either maternal buprenorphine dose at delivery or delayed entry into treatment. As previous literature suggests that high dose methadone exposure during pregnancy may be associated with smaller head circumference and that smaller head circumference may be associated with risk of neurocognitive disorders, our results further support the use of buprenorphine as a first line treatment for opioid use disorders during pregnancy.