Fetuses exposed to buprenorphine were found to have decreased head circumferences compared with non-exposed fetuses, according to findings presented at the ACOG Annual Clinical & Scientific Meeting in San Francisco.
The retrospective study, conducted by researchers from Primary Care Centers in Hazard, Kentucky, is the first to evaluate fetal head circumference over time in a group of fetuses with intrauterine buprenorphine exposure.
Researchers reviewed ultrasound reports for 3 groups of 252 patients: 75 patients in the low-dose medication-assisted therapy (MAT) group, 73 in the traditional higher-dose MAT group, and 104 in the control group.
At the time of the 20-week anatomic survey, the researchers found no statistical difference in fetal head circumference between the groups. However, at the 32-week growth scan, a comparison of the two buprenorphine groups together versus the control group showed a statistically significant difference in head circumference. Although the low-dose group had larger head circumferences than the higher-dose group in the 32-week scan, the researchers deemed the difference not significant.
The findings of this study are consistent with previous research that has shown decreased head circumference in newborns diagnosed with neonatal opioid withdrawal syndrome. However, this is the first study to confirm the findings via ultrasound.
The researchers suggested that the effects of buprenorphine exposure on fetal head circumference are more pronounced in the third trimester, and they propose interventions during pregnancy might help preserve fetal brain volume. The researchers noted the need for further research.
No potential conflicts of interest were reported.