Placental volume in pregnant women with opioid use: prenatal MRI assessment

Objective: Opioid use in pregnant women is a growing public health concern and is shown to be associated with lower infant birth weights. Placental volume changes in prior studies correlated with various maternal and fetal conditions. We aimed to identify differences between placental volumes in pregnant women with opioid use, and control pregnant women without drug use.

Methods: We prospectively recruited 27 healthy pregnant women and 17 pregnant women with opioid use disorder who were on medication-assisted treatment (MAT). All women underwent placenta/fetal MRI at 27-39 weeks gestation on a 3 Tesla MR scanner. Placental volumes were measured in a blinded fashion using a previously validated technique. Multiple linear regression was used to identify associations of placental volume with multiple maternal and fetal clinical factors. The significance threshold was set at p < .05.

Results: Placental volume was significantly associated with gestational age at MRI (p < .0001), fetal sex (p = .027), MAT with smoking (p = .0008), MAT with polysubstance use (p = .01), and maternal BMI (p = .032). Placental volume was not associated with opioid MAT alone in our cohort.

Conclusion: For pregnant women on medication-assisted treatment for opioid use disorder, there was no significant difference in placental volume compared to healthy pregnant women. However, concomitant smoking and polysubstance use in the setting of medication-assisted treatment may be detrimental to placental health. To our knowledge, this is the first study assessing placental volume in opioid use on prenatal MRI. These results support the benefit of medication-assisted treatment during pregnancy; however additional studies are needed to further elucidate the impact of opioid use on placental and fetal development and postnatal outcomes.