Breastfeeding & Birth Control

By Krista Gray, IBCLC. Last updated May 7, 2013.

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Exclusive breastfeeding can be a very effective method of birth control.  Known as LAM, or the Lactational Amenorrhea Method, there are certain criteria that must be met but, when used correctly, LAM is highly effective – even more so than progestin-only birth control pills and various barrier methods.   And it has the added bonus of not causing a hormonal disruption to your body or milk supply like many other options.

Following pregnancy and childbirth, a non-lactating woman can return to having regular menses as early as three weeks postpartum. 1  However, women who breastfeed their babies typically find their menses delayed throughout the period of exclusive nursing. Some women find they don’t have a menstrual cycle for the duration of the breastfeeding relationship, even if it lasts years.  Studies have shown LAM is more than 98% effective as birth control when three key criteria are met, as follows: 2

  1. Menstrual cycle must NOT have returned.  Your monthly menstrual cycle must not have returned following childbirth for LAM to be effective. Bleeding in the first weeks following birth, and spotting up to the first 56 days, is normal and should not be considered a return to your cycle.  However, beyond the first 8 weeks, if there is bleeding for two days or more or any bleeding you think could be your menstrual cycle; you should consider menses to have returned.
  1. Must exclusively breastfeed on demand both day and night.   Since hormonal changes in a woman’s body help suppress menses while breastfeeding, it is important to breastfeed on demand night and day in order to rely on LAM as an effective method of contraception.  Though an occasional taste of food or other liquid is permitted, it should never replace a breastfeed. 3  Like supplementation, sleeping through the night can give a woman’s body a long interval without breastfeeding which can signal the body to no longer suppress ovulation. (Yet another reason why nighttime nursing has benefits!)
  1. Baby should not be older than 6 months. LAM can be relied upon when your baby is younger than six months.  However, around the middle of the first year of life a baby typically begins to eat solid foods, which can decrease breastfeeding frequency or duration, making the chances of ovulation increase.  However, research has also shown that if a baby waits longer than 6 months to begin solids, and when beginning, continues to nurse before eating and frequently throughout the day and night, ovulation can continue to be suppressed for longer than the first six months. 4

Breastfeeding also increases the likelihood that when a mother does have a menstrual cycle the first one will not be preceded by ovulation.  Since ovulation is necessary for pregnancy to occur, this bleeding without ovulation gives a woman a “warning” that her fertility is returning and that she should consider other contraception rather than relying solely on breastfeeding through LAM. 5  

However, the longer a woman’s menstrual cycle is delayed past the first six months following birth, the greater the likelihood that ovulation will occur before the first cycle.  For example, if menses have not returned by a year, there is a much greater likelihood that a breastfeeding woman will ovulate before the first menstrual bleeding than if menstrual bleeding first occurs at six months postpartum.

When these three components are present – baby under six months old, exclusively breastfed on demand, and no return to menses – then LAM is over 98% effective as a birth control method.  It is safe for both mom and allows a couple time after birth to decide what form of contraception is right for them.

Show 5 footnotes

  1. Nichols-Johnson, Victoria.  The Breastfeeding Dyad and Contraception. Breastfeeding Abstracts November 2001, Volume 21, Number 2, pp. 11-12.
  2. Labbok, M.H. et al. Multicenter study of the lactational amenorrhea method (LAM): I. Efficacy, duration, and implications for clinical application. Contraception 1997; 55(6):327-36.
  3. Coly, Shirley. LAM – The Lactational Amenorrhea Method. World Alliance for Breastfeeding Action
  4. Kennedy, K. I. (2002). Efficacy and effectiveness of LAM. In M. K. Davis, C. Isaacs, L.A. Hanson & A.L. Wright (Eds.), Advances in experimental medicine and biology; integrating population outcomes, biological mechanisms and research methods in the study of human milk and lactation (2002/05/25 ed., pp.207-216). New York: Kluwer Academic/Plenum Publishers.
  5. Labbok, M. H. (2007). Breastfeeding, birth spacing, and family planning. In T.W. Hale & P.F. Hartmann (Eds.), Hale & Hartmann’s textbook of human lactation (pp.305-318). Amarillo, TX: Hale Publishing.