How does lactation, which delayed many years of periods, effect the onset of menopause? If I count all the years I didn't have periods because of pregnancy and then extended nursing, it might possibly add up to 11 years total. No joke. It was like getting my period for the first time after each child was close to weaning. I am now 51 and still a 26-29 day cycle. Mostly 28 days like clock work. Has anyone read any studies on this? My sister who is one year older than me has been done for a couple of years. She didn't nurse but 3 months. My mother never nursed and was done in early 50's also.