Endometrial but not Ovarian Response is Associated With Clinical Outcomes and can be Improved by Prolonged Pituitary Downregulation in Patients With Thin and Medium Endometrium

The aim of this study is to investigate the effect of ovarian and endometrial response on live birth rates (LBRs) in young normal and high responders and prolonged pituitary downregulation on endometrial receptivity and clinical outcomes in patients with different endometrial thickness. Between January 2013 and December 2017, 9511 patients underwent first in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) cycles with age ≤35 years, follicle stimulating hormone < 10 IU/l, and ≥4 retrieved oocytes were conducted. The estradiol (E2) levels on the human chorionic gonadotropin (HCG) day were classified into 4 groups: group 1 (<3000 pg/mL); group 2 (3000-5000 pg/mL); group 3 (5000-7000 pg/mL), and group 4 (≥7000 pg/mL). Logistic regression analysis was performed to predict the independent variables for live birth. Clinical outcomes between gonadotropin-releasing hormone agonist (GnRH-a) long protocol and GnRH-a prolonged protocol in patients with different endometrial thickness (EMT) were comp...