The resumption of ovulation and menstruation in a well-nourished population of women breastfeeding for an extended period of time
Lewis, P.R.; Brown, J.B.; Renfree, M.B.; Short, R.V.
Fertility and Sterility 55(3): 529-536
1991
ISSN/ISBN: 0015-0282 PMID: 2001754 Document Number: 556571
The authors studied a large group of Australian women who breastfed for a long period of time to determine the duration of lactational anovulation (n=89) and amenorrhea (n=101). Salivary progesterone assays were used to determine ovulation. These women has a mean of 322 days of anovulation and 289 of amenorrhea. Less than 20% had ovulated and 25% had menstruated by 6 months postpartum. The latest ovulation was at 750 days and the latest menstruation at 698 days. There was no significant correlation between any measure of maternal nutritional status and the duration of anovulation or amenorrhea. Neither the time of 1st supplement introduction to the baby nor the amount of supplement given was an accurate predictor of the return of ovulation or menstruation. However, these results show clearly that lactational amenorrhea can provide good protection against pregnancy in the 1st 6 months postpartum, even among well-nourished women who are providing their babies with supplement feeds.