393: Impact of methadone and tobacco exposure on fetal growth

Abstract

The incidence of small for gestational age (SGA) neonates from mothers taking methadone has been reported to be as high as 30%; however, this could be confounded by tobacco use during pregnancy. Our aim is to evaluate the incidence of intrauterine fetal growth restriction (IUGR) and SGA in fetuses exposed to (1) methadone maintenance therapy alone, (2) methadone and tobacco, (3) tobacco alone. This was a retrospective cohort study of women who delivered a live singleton at Thomas Jefferson Hospital from 2013 to 2017. In the three previously mentioned groups, we evaluated co-morbidities, including diabetes, hypertension, hepatitis infection, smoking history, third trimester fetal growth and delivery outcome. In the group of tobacco alone, women that use other substances were excluded. The primary outcome was incidence of IUGR at third trimester ultrasound and SGA. We included 450 women, 41 in the methadone alone group, 315 in the methadone and tobacco group, and 94 in the tobacco alone group. Medical conditions that may affect fetal growth were not significantly different among the three groups. The smoking cessation program for both groups had similar outcomes. The incidence of IUGR at the third trimester ultrasound was the lowest in the methadone alone group (2.4%), as compared to the methadone and tobacco group (9.8%) and the tobacco alone group (8.6%), this was not significantly different; however the incidence of AC <10th percentile was significantly lower in women in the methadone alone group. The incidence of SGA was the lowest in the methadone alone group (9.7%), as compared to the methadone and tobacco group (23.7%) and the tobacco alone group (30.1%) and this was statistically significant. (Table 1) Fetuses exposed to methadone alone had a lower incidence of IUGR and SGA, compared to methadone and tobacco exposure and tobacco alone. Previously documented rate of SGA in fetuses exposed to methadone likely related to concomitant tobacco exposure rather than methadone exposure alone.