A Description of the Imaging Innovations for Placental Assessment in Response to Environmental Pollution study (PARENTs)

Objective: The aim of PARENTs was to determine whether imaging of the placenta by novel multi-parametric MRI techniques in early pregnancy could help predict adverse pregnancy outcomes due to ischemic placental disease (IPD). Additionally, we sought to determine maternal characteristics and environmental risk factors that contribute to IPD and secondary adverse pregnancy outcomes. Study Design: Potential subjects in their first trimester of pregnancy, who agreed to MRI imaging of the placenta and measures of assessment of environmental pollution, were recruited into PARENTs, a prospective population-based cohort study. Participants were seen at three study visits during pregnancy and again at their delivery from 2015 to 2019. We collected data from interviews, chart abstractions, and imaging. Maternal biospecimens (serum, plasma, and urine) at antepartum study visits and delivery specimens (placenta, cord, and maternal blood) were collected, processed, and stored. The primary outcome was a composite of IPD, which included any of the following: placental abruption, hypertensive disease of pregnancy, fetal growth restriction (FGR), or a newborn of small-for-gestational-age (SGA). Results: In this pilot cohort, of the 190 subjects who completed pregnancy to viable delivery, 50 (26%) developed IPD. Among demographic characteristics, having a history of prior IPD in multiparous women was associated with the development of IPD. In the multiple novel perfusion measurements taken of the in vivo placenta using MRI, decreased high placental blood flow (hPBF; ml/100g/min) in early pregnancy (between 14-16 weeks) was found to be significantly associated with the later development of IPD. Conclusion: Successful recruitment of the PARENTs prospective cohort demonstrated the feasibility and acceptability of the use of MRI in human pregnancy to study the placenta in vivo and at the same time collect environmental exposure data. Analysis is ongoing and we hope these methods will assist researchers in the design of prospective imaging studies of pregnancy.