Lactation and Progression to Type 2 Diabetes Mellitus After Gestational Diabetes Mellitus: A Prospective Cohort Study

Ann Intern Med. 2015 Dec 15;163(12):889-98. doi: 10.7326/M15-0807. Epub 2015 Nov 24.


Background: Lactation improves glucose metabolism, but its role in preventing type 2 diabetes mellitus (DM) after gestational diabetes mellitus (GDM) remains uncertain.

Objective: To evaluate lactation and the 2-year incidence of DM after GDM pregnancy.

Design: Prospective, observational cohort of women with recent GDM. ( NCT01967030).

Setting: Integrated health care system.

Participants: 1035 women diagnosed with GDM who delivered singletons at 35 weeks' gestation or later and enrolled in the Study of Women, Infant Feeding and Type 2 Diabetes After GDM Pregnancy from 2008 to 2011.

Measurements: Three in-person research examinations from 6 to 9 weeks after delivery (baseline) and annual follow-up for 2 years that included 2-hour, 75-g oral glucose tolerance testing; anthropometry; and interviews. Multivariable Weibull regression models evaluated independent associations of lactation measures with incident DM adjusted for potential confounders.

Results: Of 1010 women without diabetes at baseline, 959 (95%) were evaluated up to 2 years later; 113 (11.8%) developed incident DM. There were graded inverse associations for lactation intensity at baseline with incident DM and adjusted hazard ratios of 0.64, 0.54, and 0.46 for mostly formula or mixed/inconsistent, mostly lactation, and exclusive lactation versus exclusive formula feeding, respectively (P trend = 0.016). Time-dependent lactation duration showed graded inverse associations with incident DM and adjusted hazard ratios of 0.55, 0.50, and 0.43 for greater than 2 to 5 months, greater than 5 to 10 months, and greater than 10 months, respectively, versus 0 to 2 months (P trend = 0.007). Weight change slightly attenuated hazard ratios.

Limitation: Randomized design is not feasible or desirable for clinical studies of lactation.

Conclusion: Higher lactation intensity and longer duration were independently associated with lower 2-year incidences of DM after GDM pregnancy. Lactation may prevent DM after GDM delivery.

Primary funding source: National Institute of Child Health and Human Development.

Publication types

  • Observational Study
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Blood Glucose / metabolism
  • Diabetes Mellitus, Type 2 / epidemiology*
  • Diabetes Mellitus, Type 2 / prevention & control
  • Diabetes, Gestational* / metabolism
  • Disease Progression
  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • Infant
  • Lactation / physiology*
  • Lipid Metabolism
  • Pregnancy
  • Prospective Studies
  • Risk Factors
  • Socioeconomic Factors
  • Time Factors


  • Blood Glucose

Associated data