The Effect of Baseline Bilateral Uterine Artery Doppler Velocimetry on Obstetric Outcomes in Hormonally Prepared Vitrified-Warmed Blastocyst Transfer Cycles: a Prospective Cohort Study

In hormonally prepared frozen embryo transfer cycles, basal bilateral uterine artery Doppler velocimetry will be performed before treatment (pre-conceptional) in each patient. Only patients who have high-quality blastocyst stage embryos will be included in the study. Since the implantation potential of the specified embryos is high, possible embryo-induced implantation failure would be minimized.

Bilateral uterine artery Doppler velocimetry will be performed during the basal ultrasonography (on the 2-5th day of menstruation). Any uterine artery notch, absent diastolic or reverse flow also will be recorded. 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.

A pregnancy test will be performed 9 days after embryo transfer. Pregnant patients will be called for ultrasonography control 3 weeks later to determine fetal heartbeat. Additionally, the patients will be followed till labor and any obstetric complications will be recorded.

Uterine artery Doppler ultrasonography findings in patients with and without pregnancy will be compared. Additionally, in the group in which pregnancy was achieved, obstetric results including birth weight, small-large for gestational age, presence of hypertension, and preterm labor will be correlated with baseline (pre-conceptional) uterine artery Doppler parameters.