Journal of Mammary Gland Biology and Neoplasia

, Volume 2, Issue 3, pp 291–298

Lactation and Fertility

Authors

  • Alan S. McNeilly
    • MRC Reproductive Biology Unit
Article

DOI: 10.1023/A:1026340606252

Cite this article as:
McNeilly, A.S. J Mammary Gland Biol Neoplasia (1997) 2: 291. doi:10.1023/A:1026340606252

Abstract

In almost all mammals lactation, or more correctly the suckling stimulus, induces a period of infertility designed to provide the optimal birth spacing for survival of the offspring. The duration of lactational infertility depends on the sucking activity of the young with little evidence to support a role for nutritional status. Suckling disrupts the normal pulsatile pattern of hypothalamic gonadotrophin releasing hormone (GnRH)2secretion resulting in reduced LH secretion from the pituitary. Secretion of FSH returns to its normal cyclic pattern early in lactation and ovarian follicles may develop under its influence. However, until suckling declines, the follicles fail to secrete amounts of estradiol adequate to stimulate an LH surge and ovulation. The suckling stimulus may affect GnRH secretion by affecting prolactin, opiate and dopaminergic tone in the hypothalamus but no unifying mechanism has yet been proposed convincingly. The birth spacing effects of breastfeeding in women have a profound effect on infant well-being, and breastfeeding still prevents more pregnancies than all forms of artificial contraception.

Sucklinggonadotrophinsprolactinovarian functionbirth spacing

Copyright information

© Plenum Publishing Corporation 1997