1 Introduction
Gonadotropin-releasing hormone (GnRH) antagonists are currently widely used for controlled ovarian stimulation (COS). GnRH antagonists have the advantage of preventing severe ovarian hyperstimulation syndrome (OHSS) by using GnRH agonists as the final oocyte maturation trigger instead of human chorionic gonadotropin (hCG), which has a long half-life1,2.
Preventing premature ovulation (PO) completely is difficult. However, Wu et al.3 reported three cases of pregnancy by oocyte retrieval from residual follicles after PO. Additionally, Vicdan et al.4 reported five cases of PO that were converted from in vitro fertilization (IVF) to intrauterine insemination (IUI) and two became pregnant. In most cases of PO, it is noticed and the IVF cycle is canceled. Therefore, there have been few reports of successful cases of pregnancy after PO.
We report a case of spontaneous pregnancy due to PO in a GnRH antagonist protocol. No signs of a premature luteinizing hormone (LH) surge or PO were observed, despite monitoring LH levels and the follicle count during the COS. Additionally, luteal function was maintained even after the GnRH agonist trigger so the pregnancy continued, and a healthy live neonate was delivered.