Growth hormone deficiency and pregnancy: any role for substitution?

Growth hormone (GH) is not approved for use during conception and pregnancy. Nevertheless, data from the clinical care practice reveal that most women concieve on GH replacement therapy (GHRT), and more than half continue on GHRT also during pregnancy. GH stimulates the hypothalamic-pituitary-gonadal axis at all levels, and there is evidence that GH deficiency impacts the morphology of reproductive organs, onset of puberty, ovarian function and fertility. Patients with hypopituitarism often conceive using assisted reproductive techniques and several studies support the benefit of GH supplementation for achieving fertility in women with GH deficiency. During gestation the GH system is regulated by the placental growth hormone, which increases continuously with the growth of placenta and stimulates maternal IGF-1 levels, leading to a concomitant decline in pituitary GH secretion. GHRT regimens that aim to mimic the pathophysiology of GH/IGF-1 concentrations during pregnancy continue GHRT during the first trimester, gradually reduce GH dose during the second trimester and stopp GHRT at the beginning of the third trimester. Pregnancy outcomes were not found to be related to GHRT treatment patterns during pregnancy, but female patients with childhood-onset hypopituitarism have lower fertility rates and less positive pregnancy outcomes. Although current guidelines recommend against GHRT during pregnancy, GHRT might be needed for achieving fertility and satisfactory pregnancy outcomes are reported following the decision of patients and physicians for adapting the GHRT dose during pregnancy.