(700) Timing of medication for opioid use disorder (MOUD) initiation in pregnancy and outcomes

Objective: Observe patterns of non-prescribed substance use in patients who start MOUD prior to prenatal care compared to those who begin treatment in pregnancy.

Study Design: This is an IRB-approved retrospective cohort study conducted at a single academic center. We included patients taking MOUD in pregnancy and receiving care in our comprehensive substance-use in pregnancy clinic.

Results: A total of 163 patients met inclusion criteria. Of these, 136 were identified as starting MOUD prior to their first prenatal visit in our clinic, and 27 as having started after initiating prenatal care. Patients starting MOUD prior to their first prenatal visit were older (31.6 vs 29.5 years) and had higher parity (81% vs 44% multiparous) than patients starting MOUD during pregnancy. There was no difference in the type of MOUD used. The rate of self-reported non-prescribed substance use was different between groups (prior 30.1%, during 59.3%, p=0.004). Rates of urine toxicology diagnosed non-prescribed substance use were also different between groups (prior 44.9%, during 77.8%, p=0.002).  Average gestational ages at first and last non-prescribed substance use were similar (first: prior 26.4 weeks, during 26.5 weeks, p=0.976; last: 33.9 weeks, during 32.0 weeks, p=0.422). Finally, rates of positive urine toxicology at delivery were higher in the during pregnancy group (prior 27.9%, during 66.7%, p< 0.001). When examining neonatal outcomes there were no differences in birthweight percentiles or rates of diagnosis of neonatal abstinence syndrome.

Conclusion: Patients starting MOUD prior to their first prenatal visit had lower rates of non-prescribed substance use by self-report and urine toxicology antenatally, and by urine toxicology during their delivery admission. These findings highlight the importance of community MOUD resources for all females of childbearing age, especially for those considering pregnancy. The average gestational ages at first and last positive urine toxicology were similar between groups, suggesting times that patients may be at higher risk of use and benefit from additional support.