The Effect of Baseline and First Trimester Uterine Artery Doppler Velocimetry Parameters on Obstetric Outcomes in HRT-FET Cycles: Prospective Cohort Study

Only patients with high-quality blastocyst-stage embryos will be included in the study. In frozen embryo transfer cycles prepared hormonally, basal bilateral uterine artery Doppler velocimetry will be performed before treatment (preconception) in each patient.

Bilateral uterine artery Doppler velocimetry will be performed during the basal ultrasonography (2-5 days of menstruation). The absence of any uterine artery notches, diastolic or reverse flow will also be noted. In addition, sub-endometrial (arcuate artery) blood flows will be evaluated by Doppler ultrasonography.

For endometrial preparation, estrogen replacement will be given for approximately 12-14 days as a routine In cases with endometrial thickness ≥7mm, progesterone treatment will be started and embryo transfer will be planned on the 6th day of the treatment.

In the pregnant group, measurements will be repeated at the end of the first trimester (11-14 weeks) and uterine artery Doppler velocimetry will be reevaluated. In addition, patients will be followed up until delivery and possible obstetric complications will be recorded.

Baseline and first-trimester uterine artery Doppler ultrasonography findings will be compared with obstetric results. Obstetric outcomes such as birth weight at the end of pregnancy, small-large for gestational age, presence of hypertension, and preterm delivery will be correlated with preconceptional and first-trimester uterine artery Doppler parameters.