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Breastfeeding and Fertility

Christine Foster
Mountain View CA USA
From NEW BEGINNINGS, Vol. 23 No. 5, September-October 2006, pp. 196-200.

Imagine a world where the birthrate was about 20 to 30 percent higher than it is now. Or where many more women died of cancer each year. Or where it was typical to have babies just one year apart in age. Without breastfeeding and its effect on fertility, this kind of world might exist.

Breastfeeding provides a natural delay in women's return to fertility. It can also lower cancer rates and space babies more optimally. According to the late Dr. Herbert Ratner, mothers aren't the only ones who benefit from breastfeeding infertility:

Baby's sucking controls the mother's ovulation. The more the baby has a need to suck, the less ready he is to be displaced by another. The less baby has a need to suck, the more ready and able he is to cope with a new brother or sister.

First, though, a woman needs to understand what happens to her menstrual cycle when she is nursing and how she might be able to use this knowledge to her advantage.

Breastfeeding's Contraceptive Effect

Some doctors will claim that, in a well-nourished society, breastfeeding no longer has a significant affect on fertility. They are wrong. Research shows that even in the United States, breastfeeding delays the return of most women's periods.

Almost all mothers who are fully breastfeeding their babies are free of menstrual periods for the first six months. This is called lactational amenorrhea. As THE WOMANLY ART OF BREASTFEEDING states:

Fully breastfeeding means the baby relies completely on mother for nourishment and for all of his sucking needs. Your baby's frequent nursing inhibits the release of hormones that cause your body to begin the monthly preparation for a new pregnancy. Ovulation does not take place and you do not have menstrual periods.

The exact duration of amenorrhea depends on each woman's nursing pattern and on her own physiology. According to THE BREASTFEEDING ANSWER BOOK, some women go two years or more without a period while they are breastfeeding, and some breastfeed without any supplementation and still have their menses return at a few months postpartum.

The biggest effect of breastfeeding on menstrual cycles is seen in women who practice what is known as "ecological breastfeeding." As explained by Sheila Kippley in Breastfeeding and Natural Child Spacing, the seven tenets of ecological breastfeeding are:

  1. Exclusive breastfeeding (no other liquid or solid from any other source enters the infant's mouth) for the first six months of life.
  2. Comfort your baby at the breast.
  3. Don't use bottles and pacifiers.
  4. Share sleep with your baby for night feedings.
  5. Share sleep with your baby for daily nap feedings.
  6. Nurse frequently day and night and avoid schedules.
  7. Avoid any practice that restricts nursing or separates you from your baby.

Many mothers who follow Kippley's tenets of ecological breastfeeding will experience an average of 14 months without menstruating. Mothers who breastfeed but don't do so exclusively (or don't follow all the recommendations of ecological breastfeeding) may have delay in the return of their cycles, but usually not for as long of a period of time as mothers who ecologically breastfeed.

Kristi, a California, USA mother, can say a lot about breastfeeding's ability to suppress the menstrual cycle because she's had a variety of experiences with her three weaned children. She weaned her first child at six weeks and her menstrual cycle soon returned. Her second child breastfed for seven months and soon after weaning her periods returned. She breastfed her third child until she was 30 months old and Kristi went without a menstrual period for 32 months postpartum. She says, "My deduction is that, for my body, as long as I am nursing I am able to keep [my period] at bay."

Some women who follow the seven standards of ecological breastfeeding don't always experience an extended period of amenorrhea. Jennifer Moquin considers herself "unlucky" to be one of those with an early return of menstrual periods. "My first daughter, born in 1997, was the original high need baby," says Moquin:

She never had a pacifier, never had a bottle, never slept off of my body until she was close to a year old, and nursed more than eight to 12 times per day. I got my period back at one day short of six months postpartum. My second daughter, born in 2002, was the carbon copy of her sister. In addition, I was still nursing my first child about a half-dozen times a day. I got my period back at five months. No fair, says I!

Usually, however, women who nurse as Moquin did have more time off from menstruation.

Women have long used the protection of breastfeeding to prevent pregnancy. Researchers at Georgetown University developed the Lactational Amenorrhea Method (LAM) of birth control to quantify exactly under what circumstances breastfeeding is sufficient birth control. As long as the three conditions of LAM are in place, the chances of pregnancy are less than two percent, making it a more reliable birth-spacing method than a condom or a diaphragm. The conditions for the effective use of LAM are:

  1. Baby is less than six months old.
  2. The mother's period has not yet returned.
  3. Baby is exclusively breastfed (with no pacifiers, supplemental bottles, or solid foods) and nurses on demand both day and night.

In Breastfeeding: A Guide for the Medical Profession, Dr. Ruth Lawrence explains that that it's important that mothers don't expect casual breastfeeding to limit their fertility. She writes:

A significant distinction should be made between token breastfeeding with early solids and more rigid feeding schedules and the ad lib breastfeeding around the clock with no solids until the infant is six months old. The amount and frequency of sucking are closely related to the continued amenorrhea in most women. When a totally breastfed infant sleeps through the night at an early age, requiring no suckling for six hours or more at night, the suppressive effect on menses diminishes. It has also been shown that if the infant uses a pacifier rather than receiving nonnutritive sucking at the breast, the suppression of ovulation is diminished.

When Menstruation Returns

As baby gets older, is nursing less, and eating a variety of other foods (any time the amount your baby's sucking at the breast is reduced), you should be aware that your hormone level could be affected and your menstrual cycle may resume. Breastfeeding can and should continue when menstruation resumes. Mothers sometimes notice that their babies become fussy at the start of menstruation, perhaps because many mothers have a slight, temporary drop in milk supply at the start of their period. After a few days of increased nursing, the supply will return. Some women experience moodiness and irritability. It is common for cycles to be irregular for the first few months.

Since certain patterns of breastfeeding have been shown to significantly delay the return of fertility, you may not need to consider other methods of family planning in the early months. However, as your natural period of infertility is ending, you may want to think about family planning options. Your own values and preferences will certainly influence the choices you make, as will the fact that you are breastfeeding.

If a mother is interested in natural family planning, there are several methods to help her understand her fertility pattern and recognize when she is fertile. Most women practicing natural family planning use some combination of keeping track of certain body changes that occur when fertility is returning, such as quantity of cervical mucus, position and firmness of cervix, basal body temperature, and spotting blood and/or menstrual bleeding.

Louise Monteith, a mother of three in Charleston, South Carolina, USA used the LAM method in addition to the Fertility Awareness method. The Fertility Awareness Method includes watching the body for signs of change in cervical mucus and may or may not include checking temperature and/or the cervix to indicate when a woman is likely to get pregnant. Monteith states, "My husband and I had an active sex life without a pregnancy....I paid attention to my cervical mucus to be sure that I wasn't fertile before I knew it." She has a baby now and remains happy with her method of child spacing and avoiding pregnancy.

Another method of natural family planning is the Billings Ovulation Method, which teaches women to recognize and understand the signs of fertility and infertility through observing the presence or absence of mucus at the vulva. Anabel Fitzmedrud, a teacher-trainee for the Billings Ovulation Method, says that a breastfeeding mother's body goes through a four-stage process as she goes from pregnancy, to amenorrhea, to fertility again. During the first stage, a woman is infertile. A woman doesn't have a menstrual period, but she might be able to detect some differences in her cervical mucus even before cycling begins. During the second stage, a woman experiences cyclic bleeding (anything after 56 days postpartum is counted). She is not ovulating yet, but she is having periods. Ovulation returns in the third stage. The woman releases an egg most months, but the luteal phase may be less than 10 or 11 days, which is too short to maintain a pregnancy. (The luteal phase is the time beginning with the day after ovulation and runs through the remainder of the menstrual cycle. It ends the day before a woman begins menstruating. Typically, the luteal phase lasts about 10 to 16 days in most women.) The final stage is full fertility: a woman menstruates, ovulates, and can maintain a pregnancy. Each woman goes through the same steps, but some may skip a stage.

Some women are aware of their first ovulation postpartum, especially those who keep track of their body's changes daily on a chart. In Your Fertility Signals, author Merryl Weinstein writes that by recording such things as temperature, cervical mucus, and other changes in the cervix, "in just moments per day your fertility signals will tell you whether you can or can't get pregnant." Angie Roberts, a mother of two, has gotten pregnant two times during her first postpartum ovulation. Her last period was in 1997 before she got pregnant with her son, who is now eight years old. She charted her cycle to get pregnant with her second son, who is now five, but her soon-to-be born third child, expected in October, was a surprise.

Typically, most mothers don't go from one pregnancy to another without menstruating. When menstruation does return, it can bring challenges. Shannon Rittenhouse, an LLL Leader in Virginia, USA, didn't menstruate between the birth of her first son and second son. She remembers that when she began menstruating again after her second son, it was "a doozy" because, for about six months, she had more cramping during her period than was typical for her.

If a breastfeeding mother chooses to use contraception, her safest choice would be one of the non-hormonal barrier methods, such as condoms or a diaphragm. Health professionals agree that a mother's use of spermicide does not present any problems for her nursing baby. The IUD (intrauterine device) is also thought to be safe for breastfeeding mothers.

Among hormonal methods, breastfeeding mothers should use a progestin-only type. These are less likely to have a negative effect on milk supply. (Some mothers and health professionals, however, have found that even progestin-only contraception can reduce a mother's milk production, especially when introduced too early in the course of lactation.) Mothers may wish to avoid hormonal contraceptives that contain estrogen as they have been shown to decrease milk supply in some as well as result in changes in milk composition.

There are still no conclusive studies on long-term effects of hormonal contraceptives on mother or nursing baby. For this reason, some health professionals advise that hormonal contraceptives be avoided by nursing mothers, especially when their babies are under six months of age.

Encouraging the Return of Fertility

Some mothers may relish the freedom from monthly bleeding. Gwen Fancy, an LLL Leader in Dallas, Texas, USA and mother of two girls, went without her period for two and two-and-a-half years after the births of her daughters. "It was great going without the PMS and the bother," she says. Other mothers, however, may wish their fertility would return faster. With increased knowledge, mothers can exert some control over helping their fertility return. In MOTHERING YOUR NURSING TODDLER, Norma Jane Bumgarner writes that cutting back on the frequency of nursing for six to eight weeks, especially at night, may be sufficient to cause the return of fertility.

When Alane Kasrawi's daughter, Ellie, celebrated her first birthday, Kasrawi began to panic because she wanted to get pregnant. She remembered feeling left out as a child when her sisters played together. They were four and six years older than her, and she dreamed of closer spacing for her own brood. But Kasrawi, a La Leche League Leader in Northern California, continued to nurse her baby regularly and saw no sign of her period.

Among women who nurse frequently, Kasrawi's predicament isn't uncommon. Often mothers have a plan for their fertility, but their fertility has other plans for them. Some families can adjust to a new timetable, but other mothers may need or want children closer in age.

What's a mother to do? Here are some ideas for bringing fertility back faster and for handling the balance between your existing baby's needs and your desire to give him or her a sibling:

  • Be patient. Sometimes the system works the way it does for a reason. A baby who continues to nurse constantly may not be ready for sharing mom's attention with a sibling. A delay in the return of your fertility may mean that by the time you get pregnant, you have a more mature child who can better handle a new baby in the house.
  • Make abrupt changes in your nursing routine. They tend to bring cycles back faster than gradual changes.
  • Look at the possibility of weaning for a consistent period of each day. For some mothers, night weaning is the magic answer, but for others, weaning during a chunk of the day can do the trick, too. For some mothers, just a four-hour period without nursing can help tip the hormones back into fertility.
  • If you are having periods, but your luteal phase is too short to stay pregnant, consider talking to your doctor about supplementation. Some doctors believe that can help lengthen the luteal phase and increase your chances of maintaining a pregnancy.
  • See if you can go 24 hours without nursing. In some women, that break can bring back fertility.
  • If your child is interested, feeding him more food can decrease the need for nursing.
  • Be realistic. According to THE BREASTFEEDING ANSWER BOOK, some women will find it difficult or impossible to conceive while nursing even if their menses have resumed. Most women, however, seem to be able to conceive in time.

For Kasrawi it was a combination of things that did the trick. A 24-hour break in nursing helped bring her period back two months after she started trying, but her luteal phase remained short and she had an early miscarriage five months into her effort. Finally, in her eighth month of trying, she got pregnant again and progesterone supplements helped her stay pregnant. "I am grateful that we had that extra time," she says now. "It has allowed me to better meet everyone's needs."

A Healthy Part of the Reproductive Cycle

Breastfeeding has a powerful effect on the body. Lactational amenorrhea is a normal, healthy part of the reproductive cycle that provides mothers with a natural break from fertility. Many scientists believe that extended periods of lactational amenorrhea may help to explain the lower rates of ovarian, endometrial, and breast cancer found in women who breastfeed.

Through understanding breastfeeding's affect on your menstrual cycle, evaluating your growing baby's nursing patterns, and reading the clues your body provides, you can learn to recognize when fertility returns postpartum.


Bumgarner, N.J. MOTHERING YOUR NURSING TODDLER. Schaumburg, IL: LLLI, 2000.
Kippley, S.M. Breastfeeding and Natural Child Spacing. Cincinnati, OH: CCL, 1999.
Lawrence, R. and Lawrence, R. Breastfeeding: A Guide for the Medical Profession. New Jersey: Elsevier, 2005.
Mohrbacher, N. and Stock, J. THE BREASTFEEDING ANSWER BOOK. Schaumburg, IL: LLLI, 2002.
Weinstein, M. Your Fertility Signals. St. Louis, MO: Smoothstone Press, 1989.

Helpful Web Sites

The Couple to Couple League International, Inc.

Billings Ovulation Method

Family of the Americas

La Leche League International

Lactational Amenorrhea Method (LAM)


Women's Experiences with Lactational Amenorrhea

My period returned at 22 months with no separation, use of pacifiers, or supplementation before six months.
--Rebecca, Tokyo, Japan

Baby one: my period returned at four months with almost constant nursing around the clock and no solids or pacifiers; started solids at five-and-a-half months, but only a tiny amount. Baby two: my period returned at two months and I was tandem nursing! My baby was uninterested in solids until 10 months, and even then, no significant amounts until past 18 months. Baby three: my period returned at three months with an extremely high need baby and no solids or pacifiers. Uninterested in solids until 10 months, and even then, no significant amounts until past 18 months.
--Norma, New York, USA

With my first two children, my period returned after 15 months despite their very different nursing patterns. To get pregnant with my second, I encouraged my first to stretch the time between his night nursings. I was able to get pregnant with my third without night weaning.
--Jennifer, California, USA

My period returned after six months with frequent, exclusive breastfeeding.
--Nina, Scotland

With my first child, my period returned at 17 months. With my second, it returned at 36 months. I didn't know it at the time, but I had polycystic ovary syndrome and I believe that it further delayed the return of my period. Both of my children nursed when they wanted and slept in our bed. Both also nursed past three years.
--Renee, Missouri, USA

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