This observational study will examine the safety and efficacy profile of Elonva (corifollitropin alfa) when administered in Korean women undergoing controlled ovarian stimulation (COS) in combination with a gonadotropin-releasing hormone (GnRH) antagonist for the development of multiple follicles in an assisted reproductive technology (ART) program.

Inclusion Criteria:

- Women with an indication for COS prior to in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) who meet the criteria as mentioned in the current Korean ELONVA local label

Exclusion Criteria:

• Hypersensitivity to the active substance or to any of the excipients
• Tumors of the ovary, breast, uterus, pituitary or hypothalamus
• Abnormal (not menstrual) vaginal bleeding without a known/diagnosed cause.
• Primary ovarian failure
• Ovarian cysts or enlarged ovaries
• A history of OHSS
• A previous COS cycle that resulted in more than 30 follicles ≥ 11 mm measured by ultrasound examination
• Basal antral follicle count > 20
• Fibroid tumors of the uterus incompatible with pregnancy
• Malformations of the reproductive organs incompatible with pregnancy
• Pregnancy
• Polycystic ovarian syndrome

Women participating in an ART program consisting of COS in combination with a GnRH antagonist in a general clinical setting.