Breastfeeding: Is an irregular cycle normal while nursing?

My menstrual cycles have always been on the long side (average around 29 days). My son is nine months old and still nurses about four times a day. My period started when he was about five months old. My first cycle was average, the second a little longer, but the last two have been 38 and 37 days respectively. Is this because I am still breastfeeding? If I get pregnant how will my provider even figure out my due date?


Debbi Donovan

Debbi Donovan is a Board Certified Lactation Consultant, as well as a retired La Leche League Leader. For more than a decade, Debbi... Read more

It is not unusual to have irregular periods while you are still breastfeeding. Some women even have their cycle stop temporarily if their baby begins to spend more time at the breast.  It can be frustrating if you are trying to figure out your fertile periods while all these changes are going on, and then determine if your period is just delayed, or if you might be pregnant.

You are generally considered to be fertile once your menstrual cycle has resumed, and/or you are not exclusively breastfeeding (all your baby's nutritional and sucking needs are no longer satisfied at your breast). But, if your periods are irregular, you might not be ovulating, or you might have a shortened luteal phase (the second half of your cycle -- typically days 15 through 28) with too little progesterone production to yet sustain a fertilized ovum.

You might find it helpful to begin observing signs of fertility and start to keep track of them on a calendar. Though fertility patterns in a nursing mother may not be as consistent as in a women who is not lactating, you may very well figure out your own particular pattern over a period of a month or two.

If you have an idea when you ovulated in a cycle, and if you made love within a couple days of that time, you will have a better idea whether or not there is a chance you might have actually conceived. This could also be helpful for your midwife, if you do become pregnant. If you know your date of ovulation, she can very easily figure out your due date. Your menstrual cycles will probably begin to become more regular as your little one begins weaning from the breast.

Need Advice?
Get answers from iVillage experts and other moms just like you!
Question Details
  1. Pick a subject:
Connect with 1,039,394 members just like you
Share your knowledge, ask questions.