Uterine artery impedance during puerperium in normotensive and chronic hypertensive pregnant women

Purpose: The present study compared the Doppler flow pulsatility indices (PI) in the uterine arteries (UtA) during the puerperium between healthy women and those with stage-1 essential hypertension who had uncomplicated pregnancies and delivered by elective caesarean section. The change in the mean arterial pressure (MAP) and body mass index (BMI) over time was also assessed. Methods: A longitudinal and prospective study was performed in singleton pregnancies of 28 normotensive (NT) and 24 hypertensive (HT) women. The UtA-PI was measured immediately before caesarean section (time 0) and at 1 week (time 1) and 4 weeks (time 2) postpartum. The presence or absence of early diastolic notches was recorded. The change in the MAP, BMI, and UtA-PI over time and between the two populations was modelled through multivariate linear regression using the generalised least squares. Results: In both groups, the UtA-PI significantly increased from time 0 to time 1 (p\0.05) and time 2 (p\0.05). Stage-1 hypertension did not change the trend but did increase the UtA-PI magnitude (p\0.05). The presence of uterine artery notching increased over time, from 6 to 98 %, in both groups (p\0.001); however, in the HT group, at time 1, the majority of women exhibited positive notching [92 % (HT) vs 57 % (NT), p = 0.013]. Conclusions: Chronic stage-1 hypertensive women with normal pregnancy outcomes exhibited a progressively increasing postpartum UtA impedance. This trend also occurred in normotensive women, albeit at a significantly lower magnitude.