Vascular Assessment Stratifying Preeclampsia Risk in Overweight/Obese Women

Overweight and obesity greatly increase the risk of preeclampsia. There is a need to better risk-stratify these women in pregnancy and channel resources to those who can benefit most.

Prospective observational study of 11 962 women with singleton pregnancies attending a routine assessment at 35+0 to 36+6 weeks' gestation at King's College Hospital, London, United Kingdom. Women were categorized by their body mass index at 11 to 13 weeks' gestation as normal weight (18.5-24.9 kg/m²), overweight (25.0-29.9 kg/m²), or obese (≥30 kg/m²). We recorded maternal demographics, assessed uterine artery pulsatility index and ophthalmic artery peak systolic velocity ratio, and measured carotid-to-femoral pulse-wave velocity. Preeclampsia development was retrieved from medical records. Multivariable logistic regression was undertaken to examine determinants of preeclampsia. Mediation analysis was performed to assess causal relationships.

In this cohort, 28.4% were overweight and 17.9% were obese. Preeclampsia developed more often in overweight/obese (versus normal weight) women (6.0% versus 1.7%, respectively; P<0.001); women of Black and South Asian ethnicity were at particularly increased risk (P=0.02 and 0.004, respectively). Determinants of preeclampsia development did not differ by body mass index. Mediation analysis suggested that the effect of overweight/obesity on preeclampsia development may be mediated partly by changes in maternal cardiovascular indices, particularly aortic stiffness (as reflected by carotid-to-femoral pulse-wave velocity, proportion mediated=72.6%).

Risk factors for term preeclampsia are largely similar between overweight/obese and normal-weight women, except for Black and South Asian women, who face a particularly high risk within the overweight/obese group. Maternal vascular assessment may serve as a valuable tool for stratifying the risk for term preeclampsia in these populations.