Successful Pregnancy After Aspiration and Re-transfer of a Prematurely Released Embryo During a Frozen Embryo Transfer: A Case Report.

Embryo transfer (ET) is a critical step in in vitro fertilization (IVF) and plays a pivotal role in determining implantation and pregnancy outcomes. Despite the routine use of soft catheters and real-time ultrasound guidance to ensure accurate embryo placement, procedural complications may occasionally occur. Premature release of an embryo into the lower uterine cavity or the utero-cervical junction is a rare event that may compromise implantation success. We report the case of a 36-year-old woman undergoing frozen embryo transfer (FET) of a day 5 blastocyst. Immediate post-transfer ultrasound visualization demonstrated displacement of the embryo bubble into the utero-cervical junction. Prompt aspiration of the prematurely released blastocyst was performed, followed by reloading and re-transfer into the optimal fundal region under ultrasound guidance. The patient achieved a positive human chorionic gonadotropin (β-hCG) result and developed an intrauterine pregnancy that progressed to term. An unexplained intrauterine fetal death occurred at 39 weeks' gestation. This case emphasizes the importance of continuous ultrasound monitoring during ET, rapid recognition of embryo misplacement, and meticulous coordination between clinical and embryology teams. Successful implantation and continuation of pregnancy may still be achieved following immediate retrieval and re-transfer of a prematurely released blastocyst.