Contraceptive effects of breast feeding?

Scientists are now confirming what every great grandmother used to take for granted namely, that breastfeeding both contributes to lower fertility and also increases the birth interval.

A recent article in The Lancet alleges that breastfeeding provides more than a 98 per cent contraceptive effect in the first six months after birth. A maximum birth spacing can be achieved when a mother solely or nearly solely breastfeeds her baby and does not menstruate. This could provide an easy, nutritious and cheap means of population control in third world countries, says a Lancet noticeboard follow up.