The investigators aimed to evaluate the impact of embryo distance from fundal endometrium, measured 60 minutes after transabdominal ultrasound guided embryo transfer(ET), on clinical pregnancy rates(CPR) and live birth rates(LBR) in fresh oocyte donation(OD) cycles.

Embryos were considered to be staying at the initial expulsion site for long years. However, in 1976 Edwards and Steptoe reported a tubal ectopic pregnancy after in vitro fertilization (IVF) with a day-3 embryo transfer, which may be accepted as the earliest evidence for migration of embryos from the cavity. The migration concept is very recently taken into consideration by few authors, with studies on fresh IVF and frozen ET cycles.

Oocyte donation (OD) is a method of ART, in which by using young oocytes from donors the embryo quality is optimized. OD cycles have high LBRs, and are the choice of treatment in advanced reproductive age, repeated IVF failure, premature ovarian insufficiency(POI) and particular heritable genetic diseases. Donor oocytes can be used as fresh or cryoprotected-thawed, where fresh oocytes have higher LBRs.

In the literature, there are no studies performed in fresh OD cycles about air bubble and fundus distance after ET, and there are no studies performed whether there is any embryo migration after 60 minutes of ET and its effects on CPR and LBR.

Therefore, the investigators conducted this study to evaluate the impact of embryo distance from fundal endometrium, measured 60 minutes after transabdominal USG guided ET, on CPR and LBR in fresh OD cycles. In literature, this study is first to focus on embryo migration and LBR in fresh OD cycles.

Inclusion Criteria:

• fresh oocyte donation cycles
• Anatomically anteverted-anteflexed recipient uterus
• partners with normal sperm parameters

Exclusion Criteria:

• Data of women who did not give approval
• IVF cycles
• frozen-thawed embryo transfer cycles
• cryopreserved-thawed OD cycles
• abnormal sperm parameters or need of any testicular interventions
• Anatomically retroverted-retroflexed recipient uterus
• teneculum required embryo transfers
• difficult transfers

the study was performed with women who underwent embryo transfers

The study included fresh OD cycles of recipient women.

After results are obtained we will decide.