No I will come to the rescue ruty!
Was in a bit of a rush earier... sorry if I got mixed up about who said what, its kind of hard to keep track. Just to clarify more about fertility. Yes it varies enormously between women and some women's periods return much sooner than others. However on average a woman won't have periods for 6-12 months if exclusively breastfeeding so its unlikely for her to have babies close together.
Fertility is complex but it seems that better nutrition is playing a part in women being more fertile. As we all know the age of the onset of periods is getting younger and younger. I am not suggesting that fat women are more fertile but certainly if you are underweight then you are less likely to be fertile.
Also women's idea of 'exclusive' breastfeeding can vary. Exclusive means absolutely no formula, water or even dummies. All it can take is for you to perhaps go out for awhile, express some milk into a bottle and miss a feed (it can only take 4 hours) and this is enough to disrupt the surpressing hormone to prevent you ovulating and the next thing is your periods start. Exclusive means practically having your baby glued to you day and night. Not something that a lot of modern women do and I am not suggesting that they should but it was perhaps traditionally the norm for women to just take their babies with them everywhere or wear them on a sling and this allowed more opportunties for baby to pop on and off the breast.
Here is an excerpt from K Dettwyler again ....
"There is a chapter in Breastfeeding: Biocultural Perspectives on "Breastfeeding, Fertility and Maternal Conditon," by Peter Ellison. He is an anthropologist and head of the anthropology department at Harvard University. This chapter takes a historical look at the research that has been done on understanding the links between breastfeeding and fertility, from the earliest days up to 1993, when he finished his chapter ...
Here's my brief synopsis of his thorough chapter. Suckling by the baby causes the mother's pituitary to release prolactin. It used to be thought that prolactin directly affected ovulation/fertility, but new research suggests that there is another hormone intermediate between prolactin and the ovaries. So that high levels of prolactin lead to either high or low levels of this other factor, which then affects fertility. Fertility is not an "either/or" sort of phenomenon. Post-partum, a woman does not ovulate for a while, even if she isn't breastfeeding. If she is breastfeeding frequently enough to keep her prolactin levels above her individual critical threshhold for fertility (and women vary in this threshhold) then her fertility is suppressed.
The greatest level of suppression is not ovulating, but as your prolactin levels go up, your fertility will gradually return. First you will ovulate, but not have the proper hormone levels for fertilization; then you will ovulate and fertilization may occur, but you still may not have the proper hormone levels for implantation; finally, you may ovulate, be fertilized, and implant, but not have the proper hormone levels for continuing the pregnancy, so you have a very early miscarriage, probably along the lines of minutes or hours after implantation, so you wouldn't know you had been pregnant. It is also possible to ovulate without having the right hormonal levels in the right combinations for the uterus to have been preparing for implantation, so yes, it is possible to ovulate without menstruating. For all of these stages, there seems to be incredible individual variation between women. Some women get pregnant again the first time they ovulate, with no intervening menstrual periods. I knew a woman in Indiana years ago who had three children in six years with no menstrual periods! Her doctor couldn't figure out when to predict her due date
OK I am probably the last one to post now as I will have bored everyone silly