149: Effects of medications for opioid use disorder on the fetal brain and body measurements

Abstract

Previous studies about maternal opioid use suggest a greater risk of fetal growth restriction. Limited literature was found about fetal brain and body growth and maternal prescription of medications for opioid use disorder (MOUD). We hypothesized that MOUD exposure was associated with reduction on fetal brain and body ultrasound measurements with an increased effect after co-exposure to alcohol. The ENRICH Prospective cohort study at the University of New Mexico included women who took MOUD, with or without alcohol co-exposure, and unexposed controls. Eligibility and group assignment were determined by alcohol and substance use questionnaires at enrollment and corroborated with biomarkers and assessments. Ultrasound examinations were performed at 18-22 weeks and 28-32 weeks. Measurements included standard biometric parameters and intracranial structures: frontal lobe width (FLW) and length (FLL), fronto-thalamic distance (FTD), and caval-calvarian distance (CCD). A total of 171 participants were found in the three groups (control n=56, MOUD n=75, MOUD+alcohol n=40). The sample included 166 participants who had performed an ultrasound in the second trimester and 144 in the third trimester. Compared with the control group, the MOUD only fetuses had a shorter OFD in the second trimester only, but none less than the 10th%ile. Co-exposure with alcohol was associated with several fetal brain and body measurements that were shorter than the control group in the second trimester (femur length, p=0.026; OFD, p=0.024) and third trimester (BPD, p=0.011; FTD, p=0.0084). Three participants were found to have fetal weight less than 10th%ile in their third trimester, all had alcohol co-exposure. Exposure to maternal medications for opioid use disorder does not appear to impact fetal brain and body measurements. Inquiring about maternal alcohol ingestion with these medications is recommended, because of the associated shorter lengths of several fetal brain and body measurements in the second and third trimesters.