Insulin dysregulation in women during pregnancy and/or just after birth is associated with a low supply of breast milk, data from 2 new studies conducted at Cincinnati Children's Hospital in Ohio suggest.
The first, conducted among 561 women seeking support at the hospital's Breastfeeding Medicine Clinic, found that women experiencing problems with milk supply were 2.5-times more likely to have had gestational diabetes than those who reported "latching-on" problems but had not had issues with milk supply.
The second, much smaller, study found that elevated body mass index (BMI) and glucose and insulin parameters in the prediabetic range were all predictors of insufficient milk supply in women attempting to exclusively breastfeed who had returned to the clinic at 4 weeks' postpartum with concerns.
And in other research, published online May 8 in the journal Public Health Nutrition, researchers in Columbus, Ohio found that women diagnosed with diabetes before or during pregnancy were less likely to initiate and continue breastfeeding their newborns than women without diabetes.
"We need to develop targeted therapies to support lactation success in women with a history of glucose intolerance," said Sarah Riddle, MD, a pediatrician at the Center for Breastfeeding Medicine in Cincinnati and lead author of the larger Cincinnati study, which she presented May 5 at the annual meeting of the Pediatric Academic Societies in Vancouver, British Columbia.
The smaller Cincinnati study was presented April 27 at the Experimental Biology annual meeting in San Diego, California.
First Trial of Metformin to Boost Milk Production Planned
Senior author of both Cincinnati trials, Laurie Nommsen-Rivers, PhD, from the Cincinnati Children's Perinatal Institute, told Medscape Medical News that she and her coworkers now plan to conduct a small randomized controlled study to determine whether the oral hypoglycemic agent metformin boosts milk production in prediabetic mothers.
"Women who present to the clinic with unexplainable difficulty breastfeeding will receive baseline testing, and if they have elevated fasting plasma glucose [FPG] in a range where they might benefit from improving insulin metabolism, they will be enrolled in the Metformin to Augment Low Milk Supply [MALMS] trial," Dr. Nommsen-Rivers said.
"Metformin has never been used in a randomized controlled trial to improve breast-milk supply, but based on the chain of evidence, we feel that it's worth a try," she added, noting the potential impact in a US population where 23% of reproductive-aged women are prediabetic.
Diabetes Linked to Low Milk Supply…
In the first Cincinnati study, researchers reviewed the records of a subset of 175 women who had been diagnosed with low milk supply within 90 days of birth.
"We started with the hypothesis that if metabolic dysregulation is contributing to low milk supply, women presenting with the problem would be more likely to have a history of gestational diabetes," Dr. Nommsen-Rivers explained.
Results confirmed a strong link between diabetes in pregnancy and low milk supply (odds ratio [OR], 2.6; P = .005) that remained unchanged after adjustment for covariates such as maternal and infant age (OR, 2.5; P = .008. Further analysis revealed the effect to also be independent of polycystic ovary syndrome (P = .49), hypothyroidism (P = .62), and infertility (P = .23).
The results support the hypothesis that the same contributors to gestational diabetes (ie, waning pancreatic insulin secretion in the context of insulin resistance) may also contribute to suppressed breast-milk production, Dr Nommsen-Rivers said.
…And to Problems With Breastfeeding
Meanwhile, in the research published by Reena Oza-Frank, PhD, RD, of National Children's Hospital, Columbus, Ohio, and colleagues, women with gestational diabetes were as likely to initiate breastfeeding as women without diabetes, but the gestational-diabetes sufferers were less likely to continue the practice for at least two months.
The data, from the 2009–2011 Pregnancy Risk Assessment Monitoring System (PRAMS), which is administered by the Centers for Disease Control and Prevention, showed that 8.8% of nearly 73,000 women included had gestational diabetes and 1.7% had diabetes prior to pregnancy.
Women with prepregnancy diabetes were less likely to initiate than both other groups of women but continued breastfeeding at about the same rate as women with gestational diabetes.
"We found that women with prepregnancy diabetes had the lowest breastfeeding initiation and continuation rates. However, women with gestational diabetes also had low continuation rates," Dr. Oza-Frank said.
"This study indicates that women with prepregnancy diabetes need additional support both initiating and continuing breastfeeding and that women with gestational diabetes need additional support in continuing breastfeeding."
Obese Moms Can Breastfeed; May Need Extra Support
Finally, in the second much smaller Cincinnati study, the researchers examined the issues from a different angle — by measuring insulin-related factors in 14 obese women concerned about their metabolic health (mean BMI, 32.6). All had given birth in a hospital with strong support for exclusive breastfeeding and expressed a strong intention to do so for at least 1 month.
Results at 1-month follow-up revealed significantly higher fasting plasma glucose levels among the 4 women unable to sustain exclusive breastfeeding, compared with the 10 mothers reporting either abundant or sufficient milk supply (97.2 g/dL vs 86.9 g/dL, P = .02).
"Although all 14 of these moms were overweight, other women with abundant milk supply were also overweight or even obese — yet metabolically healthy," Dr Nommsen-Rivers noted.
"We don't want to give the impression that obese moms can't breastfeed," she emphasized. "We have the convergence of a very strong public-health campaign to promote exclusive breastfeeding at the same time as we have this obesity and diabetes epidemic."
However, it is important to realize that obesity is linked to an increased risk for difficulty lactating, she observed. "Women should plan ahead of time for extra breastfeeding support with a certified lactation consultant or a pediatrician who's knowledgeable about breastfeeding. They should know where to get good follow-up care within a day or 2 of discharge," she added.
"We need to have empathy for our moms who are doing everything they can to exclusively breastfeed, while we are limited by tremendous knowledge gaps in how to help. They deserve better evidence to help support them," she concluded.
Pediatric Academic Societies and Asian Society for Pediatric Research Joint Meeting. May 3-6, 2014.
Public Health Nutr. Published online May 8, 2014. Abstract
FASEB J. 2014;28 (1, supplement 131.1). Abstract