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Subject:
From:
"Catherine Watson Genna, IBCLC" <[log in to unmask]>
Reply To:
Lactation Information and Discussion <[log in to unmask]>
Date:
Tue, 4 Nov 2003 20:22:40 -0500
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Hi Candi,
Kathryn Dewey PhD recently presented on Impact of BF on Maternal
Nutritional Status at the Academy of Breastfeeding Medicine. Her take
home message was that studies that defined breastfeeding well and
actually measured postpartum weight loss (rather than estimated it)
found an effect of breastfeeding on postpartum weight loss. Here are my
notes from that portion of her presentation:

Post partum weight change.

Estimated energy in milk secreted + cost of secreting milk = 645 kcal
per day

117,390 kical over 6 months

Little evidence of energy sparing adaptations (possibly decrease in
physical activity)

If energy intake not increased, and all energy costs met by fat
mobilization, would require 13 kg of fat.

This doesn’t usually happen, so something else must be going on. Mostly
women eat more, because they are hungrier.

Lipoprotein lipase decreases and lipid mobilization increases in femoral
region, so fat moves upward in the body, off the hips onto the arms and
upper body.

Prolactin assiciated with appetite and food intake in rodents.

Prolactin receptors are upregulated during lactation, so this probably
plays a long term role in appetite and weight regulation during lactation.

Methodological challenges of evaluating the effect of bf on postpartum
weight change

-not possible to randomly assign women to bf or not

Potential confounders

Age, ethnicity, education, income

Pre pregnancy BMI (gain less in preg, lose less with higher BMI)

Parity, interbirth interval

Physical activity and dietary practices are critical, especially the
intentional restriction of dietary intake. Once believed one can’t diet
during lactation, however women who are overweight can lose 1-2 lbs per
week and not jeopardize lactation. Restriction of 500 kcal a day below
energy needs is safe.

No studies assessed for mother’s beliefs about safety of dieting on bf.

Timing of first postpartum assessment and duration of follow-up. Best
time to do baseline is a few weeks after birth, when the extra fluid is
no longer on board. Many studies used moms prepregnancy or early
pregnancy weight or an estimate based on the moms self reported weight,
some subtracted the infant weight of the pregnancy weight gain

Weight retention can be done if it controls for pregnancy weight gain.

defining bf

Ever or not

Duration, exclusivity

Lactation score that combined duration and exclusivity.

Hondoras studies

Excl bf for 4 or 6 mos. When solids were initiated, the babies took less
breast milk, isocalorically.

Study 1 primips- mothers identical in weight avg at 4 mos, at 6 mos the
excl bf group made 100 ml more milk and lost significantly more weight
.7kg in those 2 mos, the solids feeding moms lost none.


Study 2 LBW infants

Less of a difference of milk output, and the moms that fed solids early
just lost slightly less weight than the moms who exclusively breastfed.

Studies with measured postpartum weight change:

7 total , sample sizes vary greatly, all but one done in industrialized
countries

Most had info on exclusivity

Some did body composition date

All studies showed that breastfeeding caused more weight loss except the
one that was done in Australia with any breastfeeding as a definition.

Of the studies that only estimated weight loss, only one found a
relationship. Poor quality studies did not show the weight loss
increase, but the well done studies did.

Am J Clin Nutr 1993, 58 162-6 - Dewey, Nommsen, et al - matched by
weight , bf moms lost more fat.

Janney found dose response relationship between weight loss and
breastfeeding.

McKeown & Record J endocrinology - breastfeeding moms who continued to
bf continued to lose weight. 2-3 lb difference between the early mid
late weaning groups by 12 months.

Ohlin Int J obesity 1990

Weight loss was significantly different during early lactation.

Magnitude of difference in maternal weight loss, of .6-2 kg over 12 months.

Micronutrient status - nutrient needs are substantial for certain
nutrients. Little research on the effects of lactation on maternal
micronutrient status. Extended lactation may be protective agains
tmaternal iron deficiency.

Developing countries - problems getting enough vitamin A and B6

Greatest weight loss was at 3-6 months postpartum. Kathryns theory is
that women are very hungry when prolactin levels are high initially, and
they eat to hunger. She thinks that when prolactin levels drop, the mom
is not as hungry, but she is making as much milk, so she loses weight.
After 6 mos, solids start to reduce milk intake, so mom loses less weight.

Role of breastfeeding is small compared to preg weight gain, dietary
practices, and physical activity.

Some women lose weight after weaning, they may have really high
prolactin levels, found on average there was no rebound effect after
weaning, and there was little continued weight loss after weaning, with
individual exceptions.

Greater materna weight loss: advantage or disadvantage? In the US it is
an advantage, in developing countries it could be a disadvantage, some
moms are worried about excessive weight loss so they wean. Giving these
moms more food will help them continue to bf.

Breastfed infants who don’t need iron and get it have reduced growth and
more illness.

Some anemia seen in women is not due to iron deficiency, can be malaria
or other chronic diseases.

Don’t know consequences of excessive weight loss in women who are thin.

             ***********************************************

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