Clinical usefulness of inhibin assays in Gynecology and Obstetrics

Fernando Marcos Dos Reis, Carolina Passos De Rezende

The main source of inhibin B in women is the growing follicle granulosa cells, while inhibin A is mainly produced by the corpus luteum and the placenta. In infertile women submitted to therapies of assisted reproduction, inhibin B has shown to be useful to predict a poor ovulatory response, though it has not yet overcome the performance of other markers. In the pre-natal screening of the Down syndrome, inhibin A has been repeatedly confirmed as useful in the second trimester and has also started to be considered in the first trimester test battery. Besides the two applications above, the dosage of total inhibin may contribute to the identification of cases of autoimmune ovarian insufficiency. Total inhibin may also be an auxiliary marker in the diagnosis of ovarian epithelial tumors, while the amount of inhibin B helps in the diagnosis of granulosa cells tumors. The use of inhibin A may be extended to the evaluation of pregnant women with risk of abortion, with a history of repeated abortion, with increased risk of pre-eclampsia, or even in the first days of follow-up of hydatiform mole post-emptying. All those applications are still under study, but with a real possibility of helping to extend the diagnostic spectrum of inhibin dosage in gynecology and obstetrics.