HEALTH-EFFECTS OF BREAST-FEEDING FOR MOTHERS - A CRITICAL-REVIEW

Lactation results in a number of physiological adaptations which exert direct effects on maternal health, some of which may confer both shor t and long term advantages for breast feeding mothers. Breast feeding in the early postpartum period promotes a more rapid return of the ute rus to its prepregnant state through the actions of oxytocin. Breast f eeding may also lead to a more rapid return to prepregnancy weight. Am ong studies that had good data on duration and intensity of lactation, the majority show a significant association between lactation and wei ght loss. However, there ill no evidence that lactation prevents obesi ty. Lactation also affects glucose and lipid metabolism. The long term effects of these adaptations are unknown but may have implications fo r preventing subsequent development of diabetes and heart disease. Lac tation delays the return of ovulation and significantly reduces fertil ity during the period of lactational amenorrhoea. This process is link ed with feeding patterns and may therefore be affected by practices su ch as scheduled feedings and the timing of introduction of complementa ry foods. While the evidence from epidemiologic studies is mixed, seve ral large studies have shown that extended lactation is associated wit h reduced risk of premenopausal breast, ovarian and endometrial cancer s. Although bone mineralization declines during lactation, repletion t akes place after weaning. As a result, breast feeding does not appear to cause long term depletion of bone nor does it increase risk of oste oporosis. Many of the physiological effects of lactation are dependent on the stimulation of the hypothalamic-pituitary axis and milk remova l and thus may vary with infant feeding practices. Well controlled stu dies are needed that include detailed information regarding infant fee ding practices in addition to the total duration of any breast feeding . Future feeding recommendations should reflect careful consideration of how such practices affect both infant and maternal health.