In this prospective study, the investigators aim to investigate the role of trophectoderm cells and inner cell mass cells on pregnancy outcomes in blastocyst transferred in-vitro fertilization pregnancy. The investigators will support findings with bilateral uterine artery Doppler measurements to be made between the 11th and 14th weeks of pregnancy.

Patients scheduled for thawed blastocyst transfer between May 2022 and December 2022 in Akdeniz University Hospital Center for Reproductive Endocrinology and Assisted Reproduction will be included in the study. Embryos that have reached the Blastocyst stage after the ICSI procedure will be examined by a single experienced embryologist using the ALPHA Istanbul consensus evaluation system.

This system includes separating the blastocyst from the zona pellucida - hatching (Grade 1,2,3,4), the size of ICM and arrangement (grade A, B, C), and the number of TE cells and arrangement (grade A, B, C).

Among the embryos whose quality is determined, the best quality embryo belonging to the patient will be transferred single, patients who develop pregnancy after the transfer will be called for follow-ups for uterine artery Doppler measurements to evaluate uteroplacental flow between 11and 14 weeks, and their Doppler measurements will be recorded. By contacting the patients with the phone numbers recorded at the time of the first visit, the weeks of birth, baby weight, gender, and complications that developed during the pregnancy (Abortion, Preeclampsia, Eclampsia, Fetal Growth Restriction, Oligohydramnios, Polyhydramnios, Gestational Diabetes Mellitus and Antenatal Bleeding) will be recorded.

In case the related relationship can be revealed, the risk situations in terms of complications are determined before the transfer, and it is aimed to increase the number of live births together with the risk-based management in the follow-up and screening programs.

Inclusion Criteria:

• Exogenous hormone preparation of the endometrial lining
• Single embryo transfer
• Embryo transfer at the blastocyst stage

Exclusion Criteria:

• Double embryo transfer
• Patients who underwent embryo transfer at the cleavage stage
• >15% loss of embryo viability during embryo thawing
• Patients whose data could not be accessed after follow-up or delivery

All patients aged 18-40 years who underwent a single freeze-thaw transfer on the 5th day in Akdeniz University Hospital Center for Reproductive Endocrinology and Assisted Reproduction between May 2022 and December 2022 will be included in the study.