In uncomplicated pregnancies, the uterine spiral arteries undergo a series of structural changes that result in a low resistance in the uterine arteries as pregnancy progresses.

In many pregnancies complicated with preeclampsia, growth restriction and other placental related complication, the described change does not occur. In pregnancies at high risk for placental complications, doppler measurement of Uterine artery flow has been shown to be a reliable predictor of complications.

Postpartum there is a reversal of vascular changes seen in normal pregnancies. It is unclear if there is a full reversal of these changes in complicated pregnancies with abnormal flow during pregnancy.

The investigators hypothesize that Doppler uterine artery measurements after complicated pregnancies will show some abnormality compared to doppler measurements following uncomplicated pregnancies.

The postpartum reversal of pregnancy-related changes in uterine artery (UA) flow is not well documented.

While long-term vascular changes have been noted in women with prior preeclampsia (PE), and in a dose- dependent manner, long-term changes to UA vascular resistance following PE have not been analyzed. Moreover, regardless of whether they experienced PE or intrauterine growth restriction (IUGR), it is not known if women with elevated UA pulsatility index (PI) in mid-pregnancy have higher UA well after pregnancy, compared to women whose UA PI was normal in mid-pregnancy.

The investigators propose to evaluate if UA flow remains abnormally high postpartum in women who had elevated UA flow mid-pregnancy, compared to women whose UA flow was normal in mid-pregnancy.

This is an observational prospective study. The study recruits women that have recently delivered and have undergone a Uterine Doppler ultra sound (US) during the second trimester of their pregnancy. Eligible women will undergo one post-partum ultrasound examination.

Inclusion Criteria:

• Women who underwent UA Doppler assessment at 18-22 weeks gestation.
• Viable singleton pregnancy at the time of UA Doppler assessment at 18-22 weeks gestation.
• Is at least 6 weeks postpartum following a livebirth of the aforementioned pregnancy
• Not pregnant at time of post-partum UA Doppler assessment

Exclusion Criteria:

• Women will be excluded if they do not meet the above criteria

Pregnant women

Women with singleton pregnancies.