1159 Evaluation of fetal growth restriction in pregnancies complicated by buprenorphine therapy

Abstract

To determine if a single growth ultrasound in the third trimester is as effective as serial growth ultrasounds to diagnose fetal growth restriction (FGR) in pregnancies exposed to buprenorphine therapy. This is a retrospective cohort study of pregnant women on buprenorphine opioid replacement therapy who delivered a singleton fetus at a tertiary care center between January 1, 2014 to December 31, 2019. Women were included if they had a growth ultrasound with MFM in the third trimester and at least one additional MFM ultrasound. Women served as their own control. The primary outcome was FGR, defined as estimated fetal weight less than the 10th percentile by Hadlock, on a single third trimester growth ultrasound compared to serial growth ultrasounds. Mantel-Haenszel Chi-square test was used to compare the proportion of patients diagnosed with FGR on a single ultrasound to serial ultrasounds. There were 294 pregnant women on buprenorphine therapy included in this study. The majority of the patients were single (81%), non-Hispanic white females (97%) who used tobacco (95%). Patients received an average of 3.7 ultrasounds > 20 weeks. When serial growth ultrasounds were performed, 79 fetuses were diagnosed with FGR (Table 1). Of the 79 cases, 73 fetuses were found to have FGR by evaluating a single third trimester growth ultrasound (p=0.57). The mean earliest gestational age of diagnosis of FGR was at 31w6d (SD±4w2d). In pregnant women on buprenorphine maintenance therapy, a single third trimester growth ultrasound is as effective in detecting fetal growth restriction when compared to serial growth ultrasounds. These data suggest that a single fetal growth assessment in the third trimester is sufficient for pregnant women on buprenorphine therapy. We recommend considering one growth ultrasound between 31-32 weeks to evaluate for fetal growth restriction in this population.View Large Image Figure ViewerDownload Hi-res image Download (PPT)