I have been reading the comments about LAM and it has got me wondering about the effects of long durations of ammenorrhea and bone density loss. I'm sensitive to this issue because I was without periods for a long period of time in my early twenties and subsequently broke a hip. Highly unusual for someone my age but the research supports the theory that due to low levels of estrogen bone density suffers. This is the idea behind osteopororsis in menopausal women. What research has been done with women who lactate for many years and are ammenorrhic such as the woman mentioned in one postin who only had three periods in ten years. And what about teenage mothers who have such high calcium needs for critical bone growth? Any one know of any research in this area?