Well actually, if you consider the lochia flow after birth, you need to think about sanitary supplies and leakage right away. That flow can last for almost 2 weeks depending on your activity level.
Ovulation and menstrual cycles restart at different points for different women. Many women can delay it for 6 months (or more) if they breastfeed exclusively and co-sleep so the baby has 24 hour access to the breast. However, a more common estimate is about 3 months. Regardless, if you want to avoid having your children spaced too closely, you'll want to use birth control right away and not count on a "grace period".
at 12:04 PM on Jun. 17, 2009