Physiologic Effects of Breastfeeding
There are many physiological changes that happen when a woman gives birth. There are also conditions when breast feeding helps for the mother’s fast recovery. When the mother engages in breastfeeding, the repeated suckling of the infant releases oxytocin from the mother’s pituitary gland. The function of this hormone not only signals the breasts to release milk to the baby (this is known as the milk ejection reflex, or “let-down”), but simultaneously produces contractions in the uterus. These contractions prevent postpartum hemorrhage and promote uterine involution (the return to a nonpregnant state).
Bottle-feeding mothers frequently receive synthetic oxytocin at birth through an intravenous line, but for the next few days, while they are at highest risk of postpartum hemorrhage, they are on their own. As long as a mother breastfeeds without substituting formula, foods, or pacifiers for feedings at the breast, the return of her menstrual periods is delayed (Lawrence and Lawrence 1999). Unlike bottle-feeding mothers, who typically get their periods back within six to eight weeks, breastfeeding mothers can often stay amenorrheic for several months.
This condition has the important benefit of conserving iron in the mother’s body and often provides natural spacing of pregnancies. The amount of iron a mother’s body uses in milk production is much less than the amount she would lose from menstrual bleeding. The remaining effect is a decreased risk of iron-deficiency anemia in the breastfeeding mother as compared with her formula-feeding counterpart. The longer the mother nurses and keeps her periods at bay, the stronger this effect (Institute of Medicine 1991).