Before I began taking the pill I had a very regular 28-day cycle. In the last 12 months, I have started missing periods, sometimes up to three months in a row. When I get a period again, it is always very heavy. Could I be getting pregnant and then miscarrying? Do you think that my periods will ever become as regular as they once were?

The fact that you're missing periods is likely related to the low dose of the pill. There simply is not enough estrogen to build up a good lining (endometrium) in the uterus, so there is little to shed. In addition, the body does not recognize the "fall" in hormones to start the menses because of the contraceptive's low dose.

Oral contraceptives are so effective that it is highly unlikely that you're getting pregnant and then miscarrying. Of course, birth control pills are less effective if you miss taking one or more (especially in the early part of the cycle) or you're experiencing vomiting or diarrhea. Other medications, usually antibiotics, may interact to reduce the pill's effectiveness.

This should have no effect on future fertility or on the regularity of future periods. Most women ovulate two weeks after quitting the pill. If you were regular before the pill, chances are that you will return to the same type of cycle.