I remember reading about this some time ago but the recent info from Hale's
newsletter reminded me about this correlation. Good info to keep in mind.
Prepregnant overweight and obesity diminish the prolactin response to suckling
in the first week postpartum.Rasmussen KM, Kjolhede CL.
Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853-
6301, USA. [log in to unmask]
OBJECTIVE: The population subgroups with the highest proportion of
overweight and obese women often are characterized by the lowest rates of
initiation and shortest durations of breastfeeding. We previously documented
that these 2 population-level trends may be related. In a population of white
women who lived in a rural area, we observed that prepregnant overweight
and obesity were associated with failure to initiate and also to sustain
lactation. The means by which being overweight or obese negatively affect
lactational performance is unknown and likely to be multifactorial in origin,
including the simple mechanical difficulties of latching on and proper
positioning of the infant. In addition, we have shown that prepregnant body
mass index (BMI) is negatively associated with the timing of lactogenesis II,
the onset of copious milk secretion. Although the effects of obesity on the
prolactin response to infant suckling have never been studied, we postulated
that maternal obesity could compromise this important response. We proposed
that this might occur because obesity alters the 24-hour spontaneous release
of prolactin and also because prolactin secretion is blunted in response to
various stimuli among obese subjects. The fall in progesterone concentration
that occurs immediately postpartum is the trigger for the onset of copious milk
secretion, but maintenance of prolactin and cortisol concentrations is
necessary for this trigger to be effective. Adipose tissue concentrates
progesterone. We proposed that this additional source of progesterone would
lead to consistently higher progesterone concentrations among obese
compared with normal-weight women. This, in turn, would lead to a delay in
reaching the appropriate concentration to trigger the onset of lactogenesis II.
We tested the hypotheses that a reduced prolactin response to suckling and
higher-than-normal progesterone concentration in the first week after delivery
might be among the means by which maternal overweight could compromise
early lactation. METHODS: We enrolled 40 mothers of term infants from the
same population that we studied previously. We measured serum prolactin and
progesterone concentrations by radioimmunoassay before and 30 minutes
after the beginning of a suckling episode at 48 hours and 7 days after
delivery. We used path analysis to develop a parsimonious multivariate
prediction of the prolactin response to suckling at 48 hours and 7 days
postpartum. RESULTS: As expected, prolactin values decreased from 48 hours
to 7 days postpartum. Women who were overweight or obese (using the
Institute of Medicine's cutoff for women of a BMI >26 kg/m2) before
conception had a lower prolactin response to suckling than normal-weight
women at 48 hours but not at day 7. In multivariate analyses,
overweight/obesity, primiparity, and birth weight were negatively associated
with the prolactin response to suckling at 48 hours. After adjustment for
confounding by time since delivery and the duration of the nursing episode,
only overweight/obesity remained a significant negative predictor of prolactin
response to suckling at day 7. Concentrations of progesterone decreased
dramatically from 48 hours to 7 days postpartum but did not differ between
normal-weight and overweight/obese women at either time. In addition, the
decreases in progesterone concentrations from 48 hours to 7 days postpartum
did not differ between the prepregnant BMI groups. CONCLUSION: The unique
and important finding from this study is that overweight/obese women had a
lower prolactin response to suckling. This would be expected to compromise
the ability of overweight/obese women to produce milk and, over time, could
lead to premature cessation of lactation. These findings are important
because, during our observation period (just before and after lactogenesis II,
the time of onset of copious milk secretion), the prolactin response to suckling
is more important for milk production than it is later in lactation. We have
previously shown that a high proportion of the overweight and obese women
in women in this population who give up on breastfeeding do so at this time.
This finding thus provides evidence of a biological basis for this association,
and additional study of it is likely to be informative. We postulated that there
would be consistently higher progesterone concentrations in the early
postpartum period among obese compared with normal-weight women because
adipose tissue is an extraplacental source of this hormone. This hypothesis
was not supported in this study because there were no significant differences
between normal-weight and overweight/obese women in progesterone
concentrations at either 48 hours or 7 days postpartum. The values that we
observed at these times were similar to those reported by others in the early
postpartum period. The findings from this study add plausibility to our
observation that initiation, not just duration of breastfeeding, is negatively
affected by maternal overweight/obesity. Although women should begin
pregnancy at a healthy weight and gain reasonably during gestation, not all
will. Pediatricians can help overweight/obese women to succeed at
breastfeeding by targeting them for contact with a lactation consultant before
discharge from the hospital to be sure that they have received optimal advice
on breastfeeding techniques. In addition, early contact with the mother after
discharge--by calling her at home to offer her support and counseling for
breastfeeding, by scheduling the first pediatric visit earlier than for other
patients, or by enlisting the assistance of public health nurses for a home visit
if this is possible--would help overweight/obese women to continue to
breastfeed. Being overweight or obese is negatively associated with the
prolactin response to suckling in the first week postpartum and, thus, may
contribute to early lactation failure.
PMID: 15121990 [PubMed - indexed for MEDLINE]
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