Decreased Maternal Weight Gain in Pregnancy Is Seen with Buprenorphine Medication-Assisted Treatment

Medication-assisted treatment (MAT) is associated with low maternal weight gain, and low maternal weight gain is associated with infant mortality. Many MAT patients also are smokers. This study investigates buprenorphine administration during pregnancy as a possible independent risk factor for low maternal weight gain. To our knowledge, this is the first study that compares pregnant buprenorphine patients with both smoking and nonsmoking pregnant control groups.

Our institution offers a combined MAT and prenatal care program for pregnant patients with opioid use disorder. With institutional review board approval, we retrospectively studied four groups of pregnant patients: very-low-dose (University) MAT, 83 patients; standard dose (community) MAT, 77 patients; smokers not taking MAT, 75 patients; and nonsmokers also not taking MAT, 167 patients. Informed consent was waived by the institutional review board, and standard methods were employed to maintain confidentiality. Exclusion criteria were body mass index greater than 30 at onset of care or inability to document body mass index, preterm delivery, incomplete data, intrauterine fetal demise or fetal anomaly, late prenatal care, polysubstance use, and maternal medical comorbidities.

An analysis of variance of 402 patients showed that women using buprenorphine gained less weight than women not using buprenorphine (P = 0.021). Although the very-low-dose group gained more weight (average 24.92 lb) compared with the standard-dose group (average 21.34 lb), the difference was not significant. The difference between the very-low-dose buprenorphine group and the nonsmoking, nonbuprenorphine group, as well as between the standard-dose buprenorphine group and the nonsmoking, non-buprenorphine group also were statistically significant.

Buprenorphine MAT may be an independent risk factor for decreased maternal weight gain. Given this association of maternal MAT with low birth weight, further research could explore potential advantages of nutritional supplementation for pregnant patients undergoing MAT at risk for the delivery of low-birth-weight infants.