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Pre-Pregnancy Obesity and Older Age Identified as Risk Factors for Delayed Lactation in Women with Gestational Diabetes

November 11, 2013



Pregnant woman and young child

OAKLAND, Calif. — Pre-pregnancy obesity and older maternal age are among the risk factors for delayed lactation for women with gestational diabetes mellitus, according to a Kaiser Permanente study in The American Journal of Clinical Nutrition.

The study analyzed 883 racially and ethnically diverse women to assess the incidence of delayed milk production among women with a history of GDM, or diabetes during pregnancy, and to determine whether pre-pregnancy weight was an independent risk factor even after the severity of their GDM was taken into account. The women were enrolled between September 2008 and March 2011 in the Study of Women, Infant Feeding and Type 2 Diabetes (SWIFT), an ongoing study of Kaiser Permanente Northern California members who experienced a diagnosis of gestational diabetes.

Delayed onset of lactation was reported by 33 percent of the women, and was associated with pre-pregnancy obesity, older maternal age and insulin treatment for GDM (which is indicative of greater severity of gestational diabetes).

“Given the potential for breastfeeding to mitigate the higher risk that women with GDM face for developing type-2 diabetes, skilled lactation support is particularly important for obese women with GDM,” said lead author Susana L. Matias, PhD, a postdoctoral researcher at the Kaiser Permanente Division of Research and the University of California, Davis, Department of Nutrition.

Among the study group, the average pre-pregnancy body mass index was 29.3, falling within the “overweight” category. GDM is associated with higher pre-pregnancy weight. However, even in this population, being in the heaviest BMI category (i.e., “obese”) increased the risk for delayed onset of lactation. Insulin resistance, also associated with obesity, may be another possible mechanism linking obesity and delayed onset of lactation.

Gestational diabetes mellitus, defined as glucose intolerance with first onset during pregnancy, occurs in 7 percent of all U.S. pregnancies, and affects over 200,000 women annually. A history of GDM confers up to a seven-fold higher risk of diabetes, and almost 50 percent of women with a GDM pregnancy will be diagnosed with type 2 diabetes within five to eight years after pregnancy.

Identification of risk factors for delayed milk production could help target breastfeeding support services and enable women with GDM to experience the benefits of lactation for their own future health and that of their offspring.

Lactation is characterized by increased glucose utilization and decomposition of fat through the processes for milk production, as well as higher maternal basal metabolic rates and mobilization of fat stores. Lactating women manifest lower blood glucose and insulin concentrations, and emerging evidence indicates that lactation may decrease insulin resistance.

Timely onset of milk production following delivery is important for successful breastfeeding and newborn health. Delayed onset of milk production is usually defined as not occurring until after 72 hours (or three days) postpartum, and its incidence in the U.S. is high, ranging from 23 percent to 44 percent.

“It’s important that women with GDM receive preventive support to resolve infant feeding problems early,” said senior author Erica P. Gunderson, PhD, MS, MPH, RD, a senior research scientist at the Division of Research and principal investigator of the SWIFT Study. “These risk profiles could be used to develop a screening tool for health care providers to assist mothers and their infants who may benefit from enhanced skilled breastfeeding support.”

Other studies by the Kaiser Permanente Division of Research have shown that breastfeeding with little or no formula supplementation is associated with lower fasting blood glucose and lower insulin levels in women at 6-9 weeks postpartum. The studies have also shown that exclusive or mostly breastfeeding groups had lower prevalence of pre-diabetes than formula-feeding groups, even among obese women.

Other authors on the study include Charles P. Quesenberry, Jr., PhD, of the Kaiser Permanente Division of Research, and Kathryn G. Dewey, PhD, of the University of California, Davis, Department of Nutrition.

About the Kaiser Permanente Division of Research
The Kaiser Permanente Division of Research conducts, publishes and disseminates epidemiologic and health services research to improve the health and medical care of Kaiser Permanente members and the society at large. It seeks to understand the determinants of illness and well-being and to improve the quality and cost-effectiveness of health care. Currently, the Division’s550+ staff are working on more than 350 ongoing research studies in behavioral health and aging, cancer, cardiovascular and metabolic conditions, health care delivery and policy, infectious diseases, vaccine safety and effectiveness, and women’s and children’s health. For more information, visit www.dor.kaiser.org/.       

About Kaiser Permanente
Kaiser Permanente is committed to helping shape the future of health care. We are recognized as one of America’s leading health care providers and not-for-profit health plans. Founded in 1945, our mission is to provide high-quality, affordable health care services and to improve the health of our members and the communities we serve. We currently serve approximately 9.1 million members in eight states and the District of Columbia. Care for members and patients is focused on their total health and guided by their personal physicians, specialists and team of caregivers. Our expert and caring medical teams are empowered and supported by industry-leading technology advances and tools for health promotion, disease prevention, state-of-the-art care delivery and world-class chronic disease management. Kaiser Permanente is dedicated to care innovations, clinical research, health education and the support of community health. For more information, go to kp.org/share.