Hormone imbalance, generally... there's an elaborate series of hormonal events that trigger ovulation... if this is interrupted for whatever reason, ovulation does not take place.
I was not ovulating for months and months after coming off the bcp... my body just did not kickstart itself once the pills were stopped. I didn't ovulate and didn't have periods for lamost a year. If you're not ovulating it's definitely something to see your doctor about... I ended up taking provera to jumpstart a period, and then clomid to ovulate. I did get pg but had a m/c.... but that was enough to wake my body up to start ovulating again. HTH!
at 9:02 PM on Mar. 6, 2011