The causes of ovarian hyperstimulation syndrome (OHSS) are the use of fertility medications to stimulate egg production. It arises from injections of human chorionic gonadotropin (hCG), although some very rare cases do not involve hCG. Developing OHSS becomes even more likely if pregnancy occurs while getting hCG injections. The syndrome almost never occurs in women who take fertility medications orally.
The risks for ovarian hyperstimulation syndrome include:
- Injections of human chorionic gonadotropin (hCG
- Being younger than 35
- High estrogen levels during fertility treatments
- Polycystic ovary syndrome, an imbalance of female sex hormones
- High number of large and medium follicles, the part of the ovary in which the egg develops
- Having previously had OHSS