Women with gestational diabetes could halve their risk of type 2 diabetes after delivery by breastfeeding for at least 2 months.
The study was led by researchers from Kaiser Permanente in Oakland, CA, and is published in the Annals of Internal Medicine.
Gestational diabetes is diagnosed when a woman develops high blood sugar levels during pregnancy, normally around 24 weeks' gestation.
Around 5-9% of all pregnancies in the US are affected by gestational diabetes, with around 250,000 women diagnosed with the condition every year. Women who are over the age of 35, overweight or who have a family history of diabetes are at greater risk.
According to the research team - led by Dr. Erica P. Gunderson, PhD, epidemiologist and senior research scientist at the Kaiser Permanente Division of Research - women with gestational diabetes are up to seven times more likely to develop type 2 diabetes later on.
This latest research, however, suggests breastfeeding may prevent gestational diabetes from progressing.
35-57% lower type 2 diabetes risk for breastfeeding mothers
The American Academy of Pediatrics (AAP) recommend that mothers exclusively breastfeed their infants for around 6 months. After this time, the AAP recommend continued breastfeeding for at least 1 year, alongside the introduction of complementary foods. These recommendations also apply to women with gestational diabetes.
For their study, Dr. Gunderson and colleagues set out to investigate how breastfeeding affects the risk of women with gestational diabetes developing type 2 diabetes after giving birth.
- Breastfeeding rates are on the rise in the US; in 2011, 79% of newborn infants started with breastfeeding
- Of infants born in 2011, 49% were breastfeeding at 6 months
- 27% of infants born in 2011 were breastfeeding at 12 months.
The team analyzed 1,035 women who were diagnosed with gestational diabetes and who were part of the Study of Women, Infant Feeding and Type 2 Diabetes After GDM Pregnancy (SWIFT) from 2008-2011.
All women assessed had singleton births at 35 weeks' gestation or later. At 6-9 weeks after delivery, each woman had in-person assessments that involved oral glucose tolerance testing. Such assessments were conducted again at 1 and 2 years after delivery among women who did not have diabetes at baseline.
Information on the women's infant feeding practices was also gathered on a monthly basis up to 1 year after delivery - the first study to do so, according to the authors.
Within 2 years after delivery, almost 12% of the women developed type 2 diabetes.
Compared with women who exclusively formula-fed their infants at 6-9 weeks after delivery, women who exclusively or mostly breastfed their child for at least 2 months were around 35-57% less likely to develop type 2 diabetes in the 2 years after delivery.
The risk of mothers developing type 2 diabetes reduced with greater breastfeeding intensity and longer breastfeeding duration, according to the researchers.
These findings remained after accounting for a number of potentially confounding factors, including race/ethnicity, maternal obesity prior to pregnancy, gestational weight gain, treatment for gestational diabetes, delivery by cesarean section and lifestyle behaviors.
Commenting on the implications of these results, Dr. Gunderson says:
"These findings highlight the importance of prioritizing breastfeeding education and support for women with gestational diabetes as part of early diabetes prevention efforts by health care systems."
Breastfeeding may bring other benefits for mothers. In September, Medical News Today reported on a study that found mothers with multiple sclerosis who exclusively breastfed their infants for 2 months after delivery had a lower risk of disease relapse.