There may be a correlation, that the earlier the postpartum menstrual the shorter the Luteal Phase, and the later postpartum menstrual, the longer the luteal phase. But longer doesn't necessarily mean you will get a normal length luteal phase that is 10-16. It might just mean you will be closer to having the minimum number for a luteal phase, so 8-9 instead of 4-5. And every woman is different. Some women may find the opposite to be true. When I had my first, my postpartum menstrual returned at 17 months postpartum. My luteal phase started possibly around 8, but my third cycle started at 9. With my 2nd, it came 3 days before 11 months postpartum. That is almost 6 months earlier. My Luteal Phase started around 4-5 days. Below are my charts that showed how my luteal phase changes. Breastfeeding 1st, TTC # 2 Month Postpartum Period Cycle # Length of Days Luteal Phase # Ovulation Day B6 Vitamin...