Objective: To investigate whether the limited ovarian stimulation (LOS) could avoid the severe ovarian hyperstimulation syndrome (OHSS) in patients with high risk of OHSS.
Methods: Ten infertile patients were diagnosed as polycystic ovarian syndrome (PCOS) with high risk of OHSS. All of them were arranged LOS cycles, a long-induction protocol using gonadotropin releasing hormone agonist (GnRHa) for controlled ovarian hyperstimulation. A full dose of human chorionic gonadotropin (10,000 U) was administered when the leading follicle reached a mean diameter of 12.0 - 14.5 mm. Oocytes were retrieved 36 hours later, followed by conventional in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) and embryo transfer.
Results: Ten patients produced 11 - 35 oocytes, including 4 - 28 oocytes of metaphase II. Embryos were transferred in all of ten patients and eight clinical pregnancies were diagnosed. Unfortunately, ectopic pregnancy occurred in one of the patients. None of them experienced the symptoms of OHSS.
Conclusions: LOS may play a valuable role in preventing OHSS and achieving enough mature oocytes for the patients of PCOS. Furthermore, this protocol would not reduce the pregnancy rate of the patients.