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

Uterine artery flow velocity waveforms before and after delivery in hypertensive disorders of pregnancy near term

OBJECTIVE

To compare the uterine artery pulsatility index (UtAPI-AP) before labor and immediate postpartum (UtAPI-PP) in hypertensive disorders of pregnancy (HTNP) and normotensives near term.

METHODS

Pregnancies ≥36 weeks admitted for labor induction in our institution from October 2015 to October 2017 were included. We excluded active labor, multiple gestations, fetal demise, and those with inadequate uterine artery sampling. Our primary outcome was to compare the UtAPI-AP and UtAPI-PP between subjects with HTNP (gestational hypertension, preeclampsia with and without severe features) and normotensive participants. Our secondary outcomes were to compare the UtAPI-AP and UtAPI-PP by subgroups (severe HNTP, non-severe HTNP, and controls) and the UtAPI-PP in participants while on MgSO₄ and after its discontinuation. A linear regression model was applied to test the above associations. A P < .05 was considered significant.

RESULTS

We included 108 women (HTNP = 71; controls = 37). The UtAPI-AP was higher in the HTNP group (.85 ± .3 vs. .71 ± .2; P < .001); however, the UtAPI-PP was not different between groups (1.11 ± .3 vs. 1.16 ± .4; P = .46). The UtAPI-AP was higher in the severe HTNP group than controls (P = .004), but there was no significant difference in the UtAPI-PP between subgroups. Our results remained unchanged after adjusting for confounders. The UtAPI while on MgSO₄ and after its discontinuation was similar (P =  >.99).

CONCLUSION

The increased UtAPI in patients with HTNP resolves soon after delivery. MgSO₄ does not seem to have an effect on the UtAPI postpartum.

Uterine artery pulsatility index in hypertensive pregnancies: When does the index normalize in the puerperium?

Objective

To investigate whether the uterine artery pulsatility index (UtA PI) of hypertensive pregnancies is higher than that of normal pregnancies in the puerperium, as well as in the antepartum period.

Methods

The UtA PI was measured in hypertensive (group 1) and normal pregnancies (group 2) during antepartum, immediate postpartum or late postpartum periods. Using the transvaginal approach, the bilateral uterine artery indices were measured.

Results

One hundred twenty-two women were enrolled: group 1, hypertensive disease in pregnancy (11 cases in antepartum, 13 cases in immediate postpartum and 10 cases in late postpartum period); group 2, normal pregnancies (32 cases in antepartum, 29 cases in immediate postpartum and 27 cases in late postpartum). In antepartum and immediate postpartum periods, the mean UtA PI and the proportion of cases with an early diastolic notch were higher in group 1 than in group 2 (antepartum mean UtA PI, 1.14 in group 1 vs. 0.68 in group 2, P<0.001; early diastolic notch, 46% vs. 9%, P<0.05; immediate postpartum mean UtA PI, 1.30 vs. 1.08, P<0.05; early diastolic notch, 85% vs. 48%, P<0.05). In late postpartum period, the mean value of UtA PI of group 1 was still higher than that of group 2, although the proportion of cases with an early diastolic notch was not different (mean UtA PI, 1.43 vs. 1.20, P<0.05; early diastolic notch, 60% vs. 52%, P=0.73).

Conclusion

The UtA PI in hypertensive pregnancies was still higher than normal pregnancies in puerperal periods, suggesting that more than several weeks are required to resolve increased uterine artery vascular impedance.

Postpartum uterine artery blood flow impedance following cesarean section or vaginal delivery

PURPOSE

To compare uterine arteries (UtA) blood flow after cesarean section (CS) or vaginal delivery (VD).

METHODS

We performed a prospective case-control study comparing UtA blood flow impedance in patients who delivered by CS or VD. The UtA pulsatility index (PI) was measured with Doppler ultrasound during post partum using a transabdominal convex probe. Maternal and gestational age, parity, gravidity, and delay between delivery and Doppler measurement were noted.

RESULTS

We examined 106 postnatal patients, of whom 35 had CS delivery and 71 had VD. The median delay from delivery to Doppler measurement was 35 hours for the CS group and 32 hours for the VD group. The mean PI following CS and VD was 1.62 ± 0.45 and 1.42 ± 0.47, respectively. Using a linear model, the regression coefficients for mean, right, and left PI were not significantly different depending on the mode of delivery. There was no difference between emergency and elective CS.

CONCLUSIONS

Early postpartum UtA blood flow impedance is not significantly different after CS or VD. © 2015 Wiley Periodicals, Inc. J Clin Ultrasound 44:278-283, 2016.