Increasing elevated progesterone levels on the day of human chorionic gonadotropin administration in an in vitro fertilization cycle agonist protocol had different predicted thresholds of pregnancy outcomes in different age groups: analysis of 5,566 cycles

The aim of this study was to investigate the relationships among the ages of patients, serum progesterone (P) levels on the day of human chorionic gonadotropin administration (DHCG), and clinical pregnancy rates in a gonadotropin-releasing hormone (GnRH)-agonist long protocol. A total of 5,566 patients followed at the reproductive medicine center of a tertiary care public hospital who were undergoing in vitro fertilization/intracytoplasmic sperm injection treatment with a GnRH agonist long protocol that proceeded to embryo transfer (ET) were studied. Retrospective analysis was performed and clinical pregnancy rates were calculated. With increasing serum P levels on DHCG, clinical pregnancy rates declined. The cutoff values of serum P on DHCG in patients aged ≤30 years old, 31-34 years old, and 35-37 years old were 4.5 nmol/L, 2.5 nmol/L, and 5.5 nmol/L, respectively. Logistic regression analysis showed that age and serum P on DHCG were risk factors that would affect the clinical pregnancy rate. Multiple linear regression analysis showed that in the overall sample group, the serum P levels on DHCG were positively correlated with age, total follicle-stimulating hormone (FSH) level, estradiol (E2) level on DHCG, and number of ova obtained; however, the serum P levels on DHCG showed no correlation with different age groups. Increasing the elevated serum P level on DHCG could decrease the clinical pregnancy rate, while different age groups had different cutoff values. Age was not only an important factor affecting the clinical pregnancy rate, but also affected the serum P level on DHCG.