Association of second trimester uterine artery Doppler parameters with maternal hypertension 2-7 years after delivery.

Background: Reduced uterine artery compliance is associated with adverse pregnancy outcomes (APOs) and may indicate underlying maternal cardiovascular pathology. We investigated associations between second trimester uterine artery Doppler (UAD) parameters and incident maternal hypertension 2-7 years after delivery.

Methods: A cohort of 10,038 nulliparous US participants was recruited early in pregnancy. A subgroup of 3739, without baseline hypertension and with complete follow-up visits 2-7 years after delivery, were included in this analysis. We investigated UAD indicators of compliance including: 1) early diastolic notch; 2) resistance index (RI); and 3) pulsatility index (PI). We defined hypertension as systolic blood pressure ≥130 mmHg, diastolic ≥80 mmHg, or antihypertensive medication use. We calculated odds ratios (OR) and 95 % confidence intervals (95%CI) for associations between UAD parameters and hypertension, adjusting for age, obesity, race/ethnicity, insurance, smoking, and APOs.

Results: A total of 187 (5 %) participants developed hypertension after the index pregnancy. Presence of early diastolic notch on UAD was not associated with incident hypertension. Increased RI and PI correlated with higher odds of hypertension (RI: adjusted OR 1.15 [95 % CI 1.03-1.30]; PI: adjusted OR 1.03 [95%CI 1.01-1.05] for each 0.1 unit increase). Maximum RI above 0.84 or maximum PI above 2.3 more than doubled the odds of incident hypertension (RI: adjusted OR 2.49, 95%CI 1.45-4.26; PI: adjusted OR 2.36, 95%CI 1.45-3.86).

Conclusion: Higher resistance and pulsatility indices measured on second trimester UAD were associated with increased odds of incident hypertension 2-7 years later, and may be biomarkers of higher maternal cardiovascular risk.