Clinical characteristics of preterm ovarian hyperstimulation syndrome: seven cases from China and 14 cases from the literature.

Preterm ovarian hyperstimulation syndrome (POHS) is a rare condition with only a few reported cases. The objective of this study is to investigate the clinical characteristics of 21 POHS cases (seven from China and 14 from the literature). Suspected patients (n = 7) were referred for further confirmation and data on demographics, family history, clinical manifestations (edema developed in the vulva, the hypogastric site and the upper leg), serum and sonographic assessments (ovarian cyst/cysts, gonadotropins, and estradiol levels), the natural course of patients were documented. We did not observe substantial differences in clinical manifestations among POHS patients from China relative to that from the literature. Preterm female newborns developed edema in the vulva, the hypogastric site and the upper leg at 30-39+6 weeks of post-conception age (PCA) as the major clinical manifestations. The characteristic also included high gonadotropins and estradiol, and ovarian cysts. This condition can self-resolve. Clinical manifestations of POHS patients from China are similar to those from the literature. The pathognomonic signs of POHS include vulvar, hypogastric, and upper leg edema developed at 30-39+6 PCA along with high gonadotropins and E2 values and the presence of ovarian cysts in preterm female newborns and the syndrome can self-resolve.