Spontaneous pregnancies in two women with Laron-type dwarfism: are growth hormone and circulating insulin-like growth factor mandatory for induction of ovulation?

It has recently been claimed that growth hormone (GH) and insulin-like growth factors have a role in follicular development; different mechanisms of action have been proposed. Of late, many investigators have been led by these findings to use GH and growth hormone-releasing hormone (GHRH) for induction of ovulation, in combination with human menopausal gonadotrophins. It is, however, still doubtful whether or not growth hormones and/or insulin-like growth factors are mandatory for follicular development and fertility. In this study we describe two women with Laron-type dwarfism who lacked insulin-like growth factors and who had spontaneous pregnancies. We also discuss different natural defects in the production and metabolism of growth hormone and insulin-like growth factors in humans, and the fertility performance of the affected females. It is our assumption that GH and systemic insulin-like growth factors may modulate follicular development, but that they are not necessarily mandatory for ovarian follicular development.