BRD2 and Oligomenorrhea: Diagnosis of POI was based on the European Society of Human Reproduction and Embryology (ESHRE) guidelines: (1) oligomenorrhea or amenorrhea for at least 4 months before 40 years of age and (2) an elevated follicle stimulating hormone (FSH) level >25 IU L−1 on two occasions >4 weeks apart.