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Human beings have known for centuries that breastfeeding affects fertility, and this has been borne out in recent studies. The individual variations are, however, great. In general, the more often a baby is breastfed, the younger the baby is, and the less nutrition he gets from other sources, the later the mother’s periods will resume.


The range of “normal”, though, is enormous. Some women resume their menstrual cycles soon after giving birth, while others do not resume menstruating until the baby is weaned (which can be months or years later, depending on how long the baby is nursed). This depends on how sensitive the mother’s body is, and how frequently the baby nurses. Also, some women have a non-ovulatory period before 6 months postpartum, but do not menstruate again for many months.


According to THE WOMANLY ART OF BREASTFEEDING (p. 364-366), almost all mothers who are fully breastfeeding their babies are free of menstrual periods for 3 – 6 months or longer. This is called lactational amenorrhea. Fully breastfeeding means the baby relies completely on his mother for nourishment and for all of his sucking needs. Frequent nursing inhibits the release of hormones that cause your body to begin the monthly preparations for a new pregnancy.


Even when a mother experiences a menstrual period, there is no way of knowing for certain whether or not she ovulated (released an egg and could potentially become pregnant) or if the menstrual cycles have returned permanently. You are more likely to ovulate and resume regular periods if your baby is going for more than a few hours without breastfeeding (for instance, at night) and your baby is more than 6 months old.


Most breastfeeding mothers will resume their periods between 9 and 18 months after their baby’s birth. Weaning will almost certainly cause a resumption of the menstrual cycle, but for most women is not a necessary condition, just a way to accelerate the process.


A woman who wants to use this knowledge for purposes of regulating her fertility should inform herself about the “Lactational Amenorrhea Method.” To help you learn more, the book  Breastfeeding and Natural Child Spacing by Sheila Kippley has factual information and a good deal of support on coming to terms with the effect of delayed return of your periods on the timing of growing your family.


More information on this topic may be found at our resource page for Breastfeeding and Fertility.


When the baby is not nursing for several hours daytime or at night, it is possible that you have ovulated. Therefore, you could become pregnant. If you suspect you are pregnant, you will want to check with your health care provider. Also, this would be a good time to consider a method of birth control that is compatible with breastfeeding (unless another pregnancy is desired). More information can be found at our resource page for Breastfeeding and Contraception.




It is common to have a drop in supply at certain points in your cycle, often from mid-cycle to around the time of your period. It can also be less comfortable to nurse at this time. This is due to the hormonal changes and is only temporary. Our book THE



“A daily dose of 500 to 1,000 mg of a calcium and magnesium supplement from the middle of your cycle through the first three days of your period may help minimize any drop in supply”.


Birth Control

*Parts of the contents of this page was generously supplied by La Leche League International

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