Optimum number of oocytes retrieved of follicular phase long-acting long protocol in patients with high ovarian reverse

Objective To observe the clinical characteristics and the optimum number of oocytes retrieved of follicular phase long-acting long protocol in patient with high ovarian reverse. Methods A total of 5168 patients with polycystic ovary/polycystic ovary syndrome (PCO/PCOS) underwent in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) in Reproductive Medical Center, the First Affiliated Hospital of Zhengzhou University from August 2015 to July 2019 were retrospectively identified. The cycles were divided into two groups according if “freeze all embryos” for high ovarian response, divided into groups according to whether the patients underwent moderate to severe ovarian hyperstimulation syndrome (OHSS) after embryo transfer, and divided into six groups for the number of oocytes retrieved: <6， 6-10， 11-15， 16-20， 21-25， ≥26. Clinical characteristics, clinical pregnancy rate, freeze-all rate for high response and moderate to severe OHSS rate after embryo transfer in different groups were compared. Logistic regression analysis was used to analyze the correlation of the number of oocytes retrieved to high ovarian response and the moderate or severe OHSS occurence after embryo transfer. Results In IVF cycles stimulated with follicular phase long-acting long protocol， the optimal number of oocytes for achieving clinical pregnancy was 6-10, 11-15, 16-20 （72.05%, 74.29%, 76.17%）, and also had a lower chance of all embryo frozen rate （2.46%, 10.01%, 23.59%）. The number of oocytes retrieved was associated with embryo frozen rate （OR=2.159， 95% CI=2.027-2.300， P<0.001）, and not associated with moderate to severe OHSS after embryo transfer （OR=0.755， 95% CI=0.553-1.031, P=0.077）. Conclusion The optimal number of oocytes for PCO/PCOS patient stimulated with follicular phase long-acting long protocol is between 6 and 20. Key words: Gonadotropin-releasing hormone agonist long protocol; Long-acting gonadotropin-releasing hormone agonist; High ovarian reverse; High ovarian response; Ovarian hyperstimulation syndrome