Becoming Pregnant Again

“I thought that breastfeeding was a form of birth control. Now I hear you can get pregnant while nursing, even before you start menstruating again.”

It’s true that on the average, women who nurse resume normal menstrual cycles later than those who don’t. In non-lactating mothers menstruation usually begins somewhere between four and eight weeks after delivery, whereas in lactating women the average is somewhere between three and four months. As usual, however, average are deceptive. Nursing women have been known to begin menstruation, though several variables can influence the timing. For example, frequency of feeding (more than three times a day seems to suppress ovulation better), duration of nursing (the longer you nurse, the greater the delay on ovulation), and whether or not feeding are being supplemented (your baby’s taking bottles, solids, even water, can interfere with the ovulation-suppressing effect of nursing).

Why worry about birth control before that first menstrual period? Because the point at which you ovulate for the first time after delivery is as unpredictable as when you menstruate. Some women have a sterile first period; that is, they don’t ovulate during that cycle. Others ovulate before the period, and therefore can go from pregnancy to pregnancy without ever having had menstrual period. Since you don’t know which will come first, the period or the egg, caution in the form of contraception is highly advisable.

Of course accident can happen. Medical science has yet to develop a method of contraception that is 100% effective. So even if you’ve been using contraception- and especially if you haven’t been- pregnancy is still a possibility. Unfortunately, the first symptom of pregnancy you would ordinary look for (absence of menstruation) will not be apparent if you’ve been nursing and not menstruating. But because of hormonal changes, your milk supply will probably diminish noticeably soon after a new pregnancy is established. Of course, if you do have any suspicion that you might be pregnant, the best thing to do is to visit your doctor as soon as possible. Because it is virtually impossible to do a good job of nourishing both a breastfed infant and developing fetus at the same time, it is highly inadvisable to continue nursing during a new pregnancy.

(Taken from What To Expect When You’re Expecting, ISBN 0-89480-829-X)