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Long-Term Lactation Benefits for Gestational Diabetes Patients 

Mar 3, 2020
Editor: David L. Joffe, BSPharm, CDE, FACA

Author: Chardae Whitner PharmD Candidate L|E|C|O|M Bradenton School of Pharmacy

Breastfeeding has many known long-term benefits, which include the reduction of the risk of a major disease state, a study of lactation and diabetes found.

Research has previously shown us that women who develop gestational diabetes (GDM) while pregnant are at a higher risk of developing type 2 diabetes in the future.  This 25-year study’s purpose was to identify the correlation between the duration of lactation and incidence of type 2 diabetes among women who developed gestational diabetes when pregnant.   


Participants from the Nurses’ Health Study were eligible for inclusion in this study if they reported having gestational diabetes mellitus in 1991 or having an incidence of gestational diabetes mellitus through the biennial questionnaires up to 2001, or through a survey given in 2009, which inquired about the physician diagnosis of gestational diabetes mellitus.  Exclusion criteria included reports of cancer, cardiovascular disease, multiple-birth pregnancy before the gestational diabetes mellitus pregnancy, or missing information about lactation and BMI at the age of 18.  4,372 women were included in this study conducted by the Diabetes & Women’s Health Study (DWH).   

Exposure assessments were initially given in 1993 to the participates and again in 1997 and 2003.  Assessments asked participants, “how many months in total (all births combined) did you breastfeed?” with responses ranging from <1 to ≥ 48months, and cannot remember.  NHS II biennial questionnaires were also given to participants who asked about information on potential risk factors which included medical, demographic, reproductive histories, lifestyle practices, and body weight.  In every baseline questionnaire and biennial questionnaire, participants were asked about physician-diagnosed diabetes; if participants confirmed diagnosis, a supplementary survey was given.  Participants were questioned on the symptoms, diagnostic test and treatment to confirm the diagnosis.  Phlebotomy kits were also sent to participants in 2012-2014, with participants returning the samples overnight.  The hemoglobin A1c (HbA1c), c-peptide concentrations, and insulin concentrations were all processed by a central laboratory.  

Of the 4,372 women with a history of gestational diabetes mellitus, there were 873 cases of participants who had an incident of type 2 diabetes. The results of the risk of developing type 2 diabetes were lower when lactation duration was longer.  However, there was no significant association between lactation duration and type 2 diabetes in participants regarding age, parity, primipara, pre-pregnancy BMI or period at the index gestational diabetes mellitus diagnosis. Also, a longer duration of exclusive lactation reduced the risk of developing type 2 diabetes. Furthermore, the concentrations of HbA1c, fasting insulin and c-peptide were significantly lower in participants without type 2 diabetes with longer lifetime duration of lactation.   

A clinical study showed that at three months postpartum, the favorable recovery of postpartum glucose homeostasis and insulin sensitivity is higher amongst women who begin breastfeeding early in the post-partum period. A long-term follow-up of this study also concluded that women with a previous diagnosis of gestational diabetes mellitus who breastfed longer would have lower fasting insulin and c-peptide concentrations.   

This study is one of the most significant long-term investigational studies that focus on lactation, a biomarker of glucose metabolism, and the prevention of type 2 diabetes in women with a previous history of gestational diabetes mellitus. Lactation education is promoted to pregnant women, but the results of this study show that a strong focus is needed on women who currently have gestational diabetes mellitus or recently gave birth and had a diagnosis of gestational diabetes mellitus.   

Practice Pearls: 

  • Long duration of lactation should be promoted amongst pregnant women who who are currently diagnosed with gestational diabetes mellitus. 
  • The risk of developing type 2 diabetes later in life is significantly reduced; the longer duration lactation is performed. 
  • Providers should also promote longer duration of lactation, provide patients with gestational diabetes mellitus factual data, and remind them of the complications of developing diabetes in the future.   


Ley, Sylvia H., et al. “Lactation Duration and Long-Term Risk for Incident Type 2 Diabetes in Women with a History of Gestational Diabetes Mellitus.” Diabetes Care, American Diabetes Association, 10 Feb. 2020, care.diabetesjournals.org/content/early/2020/02/10/dc19-2237. 


Chardae Whitner PharmD Candidate L|E|C|O|M Bradenton School of Pharmacy


See more about breastfeeding and diabetes.