Comparison Of Preterm Birth Rates In Patients Treated With Methadone Or Buprenorphine For Opioid Use Disorder

INTRODUCTION: Standard therapy for opioid use disorder (OUD) has been medication assisted treatment (MAT) using Methadone (MMT) or buprenorphine. Several studies have noted an increased risk of preterm birth (PTB) in women on methadone versus buprenorphine, but do not separate spontaneous or provider-initiated preterm birth. We aim to compare rates and types of PTB among pregnancies in women with OUD on MAT at our institution. METHODS: This is a retrospective cohort analysis of mother–neonate dyads with OUD on MAT who received prenatal care and delivered at a single academic institution from July 2013 to June 2018. All women in this study either received buprenorphine/naloxone (SUB) or MMT therapy during their antepartum and intrapartum care. Preterm birth was defined as delivery <37 weeks gestation. Frequencies were compared using chi-square. Multivariable analysis was used to control for possible confounders. RESULTS: We identified 718 mother–singleton neonate dyads, 22% of the cohort were treated with methadone and 78% with SUB. Overall preterm birth rate was 21.7% (156/718). MMT group had higher rates of PTB compared to SUB group (30.4% vs 19.2%, P =.003), that remained significant after controlling for smoking and history of prior preterm birth (aOR 1.84; 95% CI 1.24–2.74). However, there was no difference between rates of spontaneous PTB. CONCLUSION: In our cohort of OUD pregnant patients on MAT, the risk of overall PTB was increased in patients receiving MMT in pregnancy. However, our data suggests that this difference is only significant in provider-initiated PTB and that spontaneous PTB rates are similar between MMT and SUB.