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]

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

Archives: http://community.lsoft.com/archives/LACTNET.html
To reach list owners: [log in to unmask]
Mail all list management commands to: [log in to unmask]
COMMANDS:
1. To temporarily stop your subscription write in the body of an email: set lactnet nomail
2. To start it again: set lactnet mail
3. To unsubscribe: unsubscribe lactnet
4. To get a comprehensive list of rules and directions: get lactnet welcome