Successful pregnancy and live birth from a hypogonadotropic hypogonadism woman with low serum estradiol concentrations despite numerous oocyte maturations: a case report

BACKGROUND The increase in serum estradiol (E2) concentrations during the follicular phase becomes the index of oocyte maturation in vivo. When ovarian stimulation is performed to hypogonadotropic hypogonadism (HH) patients with only follicle stimulating hormone (FSH), proper increase in serum E2 concentrations is not observed. Even if oocytes are obtained, which usually have low fertilization rate. In this report, we would like to present an unique case, in which under low E2 concentrations and without luteinizing hormone (LH) administration, numerous mature oocytes could be obtained and a healthy baby delivered. CASE PRESENTATION During controlled ovarian stimulation (COS) with only recombinant follicular stimulating hormone (rFSH) administrations, a 26-year-old Japanese woman with hypothalamic amenorrhea (i.e., hypogonadotropic hypogonadism) developed numerous follicles despite low serum E2, 701 pg/ml, and high progesterone (P4) concentrations, 2.11 ng/ml, on the day of induced ovulation. However, 33 cumulus-oocyte complexes (COCs) were successfully obtained; following the embryo culture, four early embryos and six blastocysts were cryopreserved. This patient received hormone replacement therapy (HRT), during which one of six cryopreserved blastocysts was thawed and transferred into the uterine lumen. The patient became pregnant from the first transfer, went through her pregnancy without any complications, and delivered a healthy male baby in the 39th week. Low E2 concentrations in follicular fluids (FFs) are suggestive that aromatase and/or 17β-hydroxysteroid dehydrogenase (17β-HSD) could be low. CONCLUSIONS Serum E2 concentrations may not be the most important index for oocyte maturation during COS, and suggested that oocyte maturation was in progress even under low serum E2 and high P4 conditions. Even if serum E2 concentrations did not properly increase, numerous mature oocytes could be obtained, resulting in the birth of a healthy baby.