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.
The researchers aim to determine how baseline (preconceptional) and first-trimester uterine artery Doppler measurements affect obstetric complications in women undergoing high-quality blastocyst transfer and to determine the correlation between the two Doppler measurements.