Breastfeeding and Mom's weight loss - research

[Carolyn Gleason]

From:  MCH Alert
National Center for Education in Maternal and Child Health
http://www.ncemch.org/alert

February 18, 2000


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EFFECTS OF WEIGHT LOSS IN OVERWEIGHT, LACTATING WOMEN ON INFANT GROWTH

A study in this week's New England Journal of Medicine finds that weight loss
of approximately 0.5 kg per week between 4-14 weeks postpartum in overweight
women who are breastfeeding does not affect the growth of their infants.  In the
10-week intervention, 40 overweight lactating women were randomly assigned to a
diet-and-exercise group (that restricted energy intake by 500 kcal daily and
exercised 45 minutes per day for four days per week) or a control group (that
maintained their normal dietary intake and did not exercise more than once
weekly). 
Though the women in the diet-and-exercise group lost more weight and fat mass,
the
gains in weight and length of the infants whose mothers were in the
diet-and-exercise group were not significantly different from infants whose
mothers were in
the control group.

Study findings support an Institute of Medicine statement that weight loss of
up to 2 kg per month in overweight women seems to be safe and that weight loss
of
more than 2 kg per month is not advisable for breast-feeding women. 
Researchers note that their findings may differ for women with body-mass-index
values less
than 25.  Study participants had an average percentage of body fat of 33.8% and
had adequate energy reserves.

An accompanying editorial highlights the need to interpret the results with
caution, as "[t]he large standard deviation in weight gain of the infants
suggests
that the growth of some infants might have been inadequate."  Additionally,
factors such as mood and fatigue should be evaluated to more fully understand
the
effects of dieting on new mothers as well as their infants.  The editorial
states
that "[if] diet is to be prescribed for lactating women, it is important to
review their energy requirements and to recommend energy intake that is only
moderately restrictive."  Further, "[d]iet-and-exercise programs may be
advisably
postponed until four to six months postpartum, when a mother's milk is no longer
the
sole source of nutrition for her infant."

According to the editorial, alternatives to an emphasis on postpartum weight
loss should be considered:  "For the health and well-being of both mothers and
infants, the nutritional aim should be to achieve balance in maternal weight and
body composition over the entire reproductive cycle, not only in the early
postpartum period."

Lovelady, Cheryl A., et al.  "The Effect of Weight Loss in Overweight,
Lactating Women on the Growth of Their Infants."  The New England Journal of
Medicine. 
2000; 342(7): 449-453.

Butte, Nancy F.  "Dieting and Exercise in Overweight, Lactating Women."  The
New England Journal of Medicine.  2000; 342(7): 502-503.