Antepartum and postpartum uterine artery impedance in women with pre-eclampsia: a case control study.

This is a cohort study which included 100 cases with pre-eclampsia (PE) and 100 controls, done to compare the antepartum and postpartum uterine artery (UtA) Doppler velocimetry between them. UtA PI and RI were measured before and within 48-72 h after delivery. There was a highly significant difference between the cases and controls, regarding the UtA RI (0.70 ± 0.10 and 0.72 ± 0.10, versus 0.59 ± 0.12 and 0.60 ± 0.11) and PI (1.41 ± 0.89 and 1.45 ± 0.90 versus 0.85 ± 0.30 and 0.90 ± 0.34) measured at the antepartum and postpartum periods, respectively. Age and gestational age were significantly related to the postpartum and changes in the UtA PI. The gestational age was also correlated to UtA RI changes. Both the antepartum and postpartum mean blood pressure were correlated with postpartum UtA RI and PI and PI changes after delivery. We concluded that uterine artery Doppler indices changes are more common in women with PE, than in normotensive women with significant correlations with age and gestational age. Impact statement What is already known on this subject? After delivery, the haemodynamic changes that occurred with pregnancy reverse. Both the heart rate and the cardiac output decreased to reach the non-pregnant state. Impedance to flow in the uterine artery rises as the nutritional needs are decreased abruptly. What do the results of this study add? Both the antepartum and postpartum measurement of uterine artery Doppler indices is significantly higher in women with PE when compared to control women. The persistent uterine artery impedance is a result of inadequate trophoblastic invasion within the basal part of the decidua basalis and myometrium or persistently increased maternal vascular tone. What are the implications of these findings for clinical practice and/or further research? The uterine artery Doppler parameters return to the non-pregnant values in normal pregnancies. Knowing such information may help in understanding the haemodynamics of the uterine vasculature during puerperium in hypertensive patients.