I've been having very abnormal periods for over 2 yrs since i had a baby. every 2nd cycle is 30-40 days long. than back to 27-30 day cycle. why???

Cycle variations: Every ovulatory cycle may be different, and depending on when ovulation (production of an egg) occurs, The one constant is the time from ovulation until the start of the next period: 14 days. So, a 27-28 day cycle will ovulate on day 14-15, and a 30-40 day cycle ovulates on day 16-26. It depends on when the egg is released from the ovarian Some eggs take longer to mature, hence the difference.