Menstruation and Breastfeeding
Human beings have known for centuries that breastfeeding affects fertility, and this has been borne out in recent studies. The effects of breastfeeding on fertility vary greatly between individuals. In general though, the more often your baby is breastfed, the younger your baby is, and the less nutrition they get from other sources, the later your periods will resume.
The range of “normal”, is enormous. Some women resume their menstrual cycles soon after giving birth, while other people do not resume menstruating until the baby is weaned (which can be months or years later, depending on how long the baby is nursed). Individual hormonal and physiological differences can play a part as can how frequently the baby nurses. Also, some people 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 everyone who is fully breastfeeding their babies will be free of menstrual periods for 3 – 6 months or longer. This is called lactational amenorrhea. Fully breastfeeding means the baby relies completely on breastfeeding for nourishment and for all sucking needs. Frequent nursing inhibits the release of hormones that cause your body to begin the monthly preparations for a new pregnancy.
Experiencing a menstrual period does not mean that your menstrual cycle has returned permanently and without an accurate clinical test, you won’t know whether or not you ovulated (released an egg and could potentially become pregnant). 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 your baby will almost certainly cause your menstrual cycle to return, but most people find that they do not need to wean in order for their cycle to gradually resume. If you want to use this knowledge for purposes of regulating your fertility you may find it helpful to read more about the “Lactational Amenorrhea Method.” The book Breastfeeding and Natural Child Spacing by Sheila Kippley also offers factual information and 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 can be found at our resource page for Breastfeeding and Fertility.
Once your baby is not nursing for several hours at a time during daytime or at night, it is possible that you will ovulate. 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.
DOES YOUR PERIOD DECREASE YOUR MILK SUPPLY?
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 Womanly Art of Breastfeeding states that:
“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”.
Updated January 2021.