Premature ovarian insufficiency (POI) is highly heterogeneous, both in phenotype and etiology. They are not yet clearly stated and correlated.

To characterize clinical presentations of a large, well-phenotyped cohort of women with POI, and correlate phenotypes with etiologies to draw a comprehensive clinical picture of POI.

In this retrospective study, a total of 955 Chinese women with overt POI between 2006 and 2015 were systemically evaluated and analyzed. The phenotypic features, including menstrual characteristics, hormone profiles, ovarian ultrasonography/biopsy, pregnancy/family history, and genetic/autoimmune/iatrogenic etiologies were assessed and further compared within different subgroups.

Among 955 women with POI, 85.97% presented with secondary amenorrhea (SA) and 14.03% with primary amenorrhea (PA). PA represented the most severe ovarian dysfunction and more chromosomal aberrations than SA. The decline of ovarian function in patients with SA progressed quickly. They had shortened reproductive periods (approximately 10 years) and developed amenorrhea within 1 to 2 years after menstrual irregularity. The ovaries were invisible or small, and the presence of follicles (28.43%) was correlated with other good reproductive indicators. Familial patients (12.25%) manifested better ovarian status and fewer chromosomal aberrations than sporadic patients. The etiologies consisted of genetic (13.15%), autoimmune (12.04%), and iatrogenic (7.29%), approximately 68% remaining idiopathic. There were significant differences among different etiologies, with the genetic group representing the most severe phenotype.

Our results regarding distinct phenotypic characteristics and association with different etiologies further confirmed the high heterogeneity of POI. Additional longitudinal clinical studies and pathogenesis research are warranted.