Arterial Resistance in Late First Trimester as a Predictor of Subsequent Pregnancy-Related Hypertension

Abstract

Objectives: This study aimed to examine the association between indicators of arterial resistance occurring late in the first trimester and the subsequent development of pregnancy-related hypertension. Methods: This study took place between May 2014 and August 2015 and included 329 consecutive women with singleton pregnancies attending the antenatal clinics of a medical college in Karnataka, India, during this period. Pulse pressure (PP) and uterine artery Doppler parameters were recorded between 11–14 gestational weeks. Consequently, women were followed-up until after delivery for subsequent hypertension. Results: Hypertension occurred more frequently if PP was high (17.6% versus 14.4% of pregnancies without high PP; P = 0.713), if a diastolic notch (DN) was present (15.1% versus 12.8% of pregnancies with an absent DN; P = 0.612) and if the resistive index (RI) was raised (22.2% versus 14.3% of pregnancies without raised RI; P = 0.366). A raised pulsatility index (PI) was significantly associated with hypertension (P = 0.013). The risk of hypertension was approximately seven-fold higher if two or more arterial resistance indicators were used, except with a present DN plus a raised RI or a present DN plus high PP. All arterial resistance indicators showed negative predictability (>85.6%) and good specificity (≥95.0%), except for the presence of a DN. A population-specific cut-off PI value of 1.72 had high negative predictability (92.8%) and good sensitivity (70.8%) and specificity (65.1%). Conclusion: Raised PI in the late first trimester was a significant predictor of hypertension later in pregnancy. A combination of arterial resistance indicators may enhance prediction of subsequent hypertension.