Number of ovarian follicles in human fetuses with the 45,X karyotype

OBJECTIVE: To evaluate the numbers of ovarian follicles during fetal life in the gonads of human female fetuses with the 45,X karyotype (Turner syndrome, TS) and to compare them with those from age-matched 46,XX fetuses. DESIGN: Retrospective study. SETTING: An academic hospital. PATIENT(S): Ovarian samples from TS fetuses (aged 17-37 weeks), mainly obtained after induced abortion, and ovaries from eight control fetuses (matching gestational ages). INTERVENTION(S): Embedded blocks of ovaries were collected from anatomy-pathology departments of three university hospitals and were sectioned and stained with hematoxylin-eosin. MAIN OUTCOME MEASURE(S): Observation of primordial and growing follicles. RESULT(S): In the fetal ovaries of controls, numerous oogonia were observed at 18 weeks. Primordial follicles were present in all ovaries from 20 weeks' gestation onward, whereas preantral and antral follicles were observed from 26 weeks onwards. In ovaries from 45,X TS fetuses, oogonia were observed in some ovaries, but no primordial, preantral, or antral follicles were found, even in ovaries from the third trimester of gestation. CONCLUSION(S): Follicle formation and growth are severely reduced in ovaries from aborted 45,X TS fetuses.