The generally positive health effects of breastfeeding upon children are often discussed. Mothers do not always learn, or learn much, about the profound and amazing physical changes that breastfeeding brings about in their own bodies. Yet since its very beginnings, humankind has relied upon these changes for its very survival.
Lactogenesis I
The first phase of lactogenesis, the development of the mother's ability to nurse her baby, begins by mid-pregnancy. The mother's breasts enlarge and become capable of secreting colostrum, a form of milk that is thicker, higher in protein, lower in fat and more digestible to a very newly born infant than the kind that arrives soon after birth. (See Reference 1 pages 73-74.)
Lactogenesis II
The "coming in" of thinner, more plentiful milk marks the second phase of lactogenesis, usually 2 to 8 days post-birth. Following delivery of the placenta, the mother's blood levels of progesterone and possibly estrogen drop steeply, leading to the release of the hormones prolactin and oxytocin. In concert with nipple stimulation from the baby's mouth or from a breast pump, prolactin and oxytocin establish the mother's milk supply. Nursing shrinks the uterus more quickly to its pre-pregnancy size and may reduce the mother's risk of birth hemorrhage.
After Milk Supply Establishment
Prolactin enables a mother with regularly stimulated nipples to sustain and even expand her milk supply. Some women fear being "sucked dry"; however, with breastfeeding, supply generally follows closely upon demand. Released in response to suckling, oxytocin triggers the milk-ejection reflex or "letdown." As well as feeling tingly and warm, oxytocin release can be calming and stress-buffering for nursing mothers. As the mother weans her child, her prolactin and oxytocin levels fall until her milk-producing ability disappears.
Fertility and Family Planning
The hormonal changes of breastfeeding can suppress monthly ovulation. This is the basis of the Lactational Amenorrhea Method of birth control, or LAM. Taught by knowledgeable health workers and correctly and consistently practiced, LAM can be up to 98 percent effective; however, many women prefer to use a second method as well, or completely rely on family planning other than LAM. The World Alliance for Breastfeeding Action recommends first, nonhormonal methods and second, progestin-only pills, as estrogen-containing contraceptives can diminish the mother's milk supply.
Metabolism and Nutrition
The fertility-suppressing ability of breastfeeding probably evolved to protect women's bodily energy and protein stores from depletion through too closely spaced children. According to the Rehydration Project, most nursing mothers need an extra 500 calories per day, as well as extra fluids. All but the most severely malnourished women can make enough breast milk for their babies. But well-balanced, varied diets ensure the best possible nutrition and health for nursing mothers as well as children.
Long-Term Health Benefits
As Dr. Alicia Dermer notes on the La Leche League International website, breastfeeding mothers tend to lose weight more quickly and keep it off more effectively than their nonbreastfeeding peers. Breastfeeding women also appear to have lower risks of heart disease, osteoporosis, and certain reproductive cancers, including breast cancer. Women with gestational or type 1 diabetes who breastfeed tend to have lower blood sugars and better blood lipid profiles. Lactation may also alleviate flare-ups of maternal rheumatoid arthritis.
References
- "Breastfeeding and Human Lactation"; Jan Riordan; 2005
- La Leche League International : A Well-Kept Secret-Breastfeeding's Benefits to Mothers; Alicia Dermer; 2007
- Rehydration Project: Breastfeeding and Maternal Nutrition; Frequently Asked Questions (FAQ)
- United States Department of Agriculture: Daily Food Plans for Pregnancy & Breastfeeding
- World Alliance for Breastfeeding Action : Family Planning for The Breastfeeding Woman
- World Alliance for Breastfeeding Action Lactational Amenorrhea Method (LAM)
