Live birth of a healthy baby from slow-freezing cryopreserved pronuclear stage embryos warmed using a standard devitrification protocol: Case report

Abstract

Before a new embryo transfer attempt was performed, both the patient and her husband were fully informed on the circumstances involving the procedure, and consented to having their embryos warmed through the standard devitrification procedure. Slow-freezing cryopreservationA 36-year-old patient began infertility treatment in 2003 due to male factor. The stimulation cycle was initiated with 300 UI/day of GnRH analog (Synarel -Zodiac, São Paulo, Brazil) during 21 days, followed by 150 UI of hMG (Merional -Mezler, São Paulo, Brazil). Serial transvaginal ultrasound was performed to monitor and control follicular growth and endometrial thickness. Recombinant hCG (Ovidrel -Merk, São Paulo, Brazil) was administered on the night of the eleventh day of the cycle, followed by transvaginal ultrasound--guided oocyte retrieval 35 to 36 hours later. After oocyte aspiration, cumulus cells were removed from all oocytes and twelve mature metaphase II (MII) oocytes were selected out of twenty three. Intracytoplasmic sperm injection (ICSI) was performed in all twelve MII oocytes, and after 16h in controlled culture (37oC and 6% CO2 atmosphere), they were checked for fertilization. Two pro-nuclei were observed in 10 out of the 12 injected oocytes. Six pronuclear stage embryos were cryopreserved while four embryos were kept in culture until day 3, when they were loaded into a Sydney IVF embryo transfer catheter (Cook IVF -Brisbane, Australia), and transferred into the uterine lumen under trans-abdominal ultrasound guidance. β-hCG serum levels were measured 12 days after embryo transfer to determine biochemical pregnancy. Transvaginal ultrasound was performed at 6 weeks of gestation to confirm clinical pregnancy, which consisted of two gestational sacs and one heartbeat. The result was the birth of a healthy boy.