Ovarian stimulation by promoting basal follicular growth.

Abstract

Background: Most methods of ovarian stimulation rely on gonadotropin modulation. However, abnormal anti-Müllerian hormone concentrations are frequent in infertility, suggesting that defects in the gonadotropin-independent period of folliculogenesis preceding cyclic recruitment (i.e., basal follicular growth) may often occur. We need to better understand basal follicular growth and determine how to improve it.

Methods: Section I summarizes a literature search concerning preantral and early antral folliculogenesis, cyclic recruitment, and selection. Section II presents current knowledge about interventions involving early antral folliculogenesis and cyclic recruitment.

Results: While folliculogenesis following cyclic recruitment is gonadotropin-dependent, basal follicular growth is not. Basal follicular growth is regulated by follicle-stimulating hormone and local communication between the oocyte and its granulosa and thecal cells involving gap junctions and many autocrine/paracrine factors. This local communication sustains growth synergistically with follicle-stimulating hormone, but also suppresses this hormone to induce granulosa cell differentiation. As a follicle develops, its responsiveness to gonadotropin progressively increases. Section II describes 4 interventions affecting early antral folliculogenesis, including granulocyte colony-stimulating factor priming, bromocriptine rebound, carbohydrate metabolism intervention, and danazol priming, which have improved embryo development and live birth rate in patients with previous failures.

Conclusion: Basal follicular growth modulation can increase live birth rates.