Although the World Health Organization (WHO) encourages breastfeeding, the rate of breastfeeding among women with gestational diabetes mellitus (GDM) is declining . The primary cause, of course, is the concern of mothers with GDM about the quality of their milk.
Breast milk is supposed to be the best food for babies, but gestational diabetes mellitus (GDM) brings a range of uncertainties, leading to the decline in breastfeeding rate of mothers with gestational diabetes mellitus (GDM). Therefore, if the changes in milk were explained in detail for mothers with GDM, it might be possible to increase breastfeeding rates.
The Amount of Lactose in Milk Is Relatively Stable, Which Does Not Cause an Increase in the Baby’s Blood Sugar
The logic of some mothers with GDM is as follows: “"a mother’s elevated blood glucose may lead to an increase in glucose in the milk, and thus the milk becomes sweeter, which would expose the baby to greater chances of getting high blood glucose." However, this is not the case at all.
The only carbohydrate in milk is lactose, not glucose . Lactose is produced by lactose synthetase in the mammary gland after glucose and galactose are linked by the β1, 4-glucoside bond. Due to the restriction of lactose synthase and osmotic pressure, although the glucose content in the blood of mothers with GDM increases, it only increases the matrix for synthesizing lactose. The amount of lactose in milk hardly changed; and thus it does not affect infant blood sugar much.
Elevated Insulin Level in Breast Milk Is Beneficial to Neonatal Weight Control
People with diabetes deliberately inject insulin into their body in order to control their blood glucose. Researches showed that   Insulin levels in milk of women with GDM are higher than those of normal breast milk, regardless of how they control their blood glucose (either by insulin or lifestyle changes). Although this fact brings concerns to mothers with GDM, actually elevated insulin level, in fact, has a positive effect on babies of women with GDM.
Most babies born to women with GDM face a greater risk of being fetal-macrosomia, being overweight, developing type 1 diabetes and even developing metabolic syndrome in adulthood. There is a negative correlation between insulin levels in mature milk at 42 days and weight gain from birth to 42 days; and the insulin levels in mature milk at 90 days are negatively correlated with infant’s head circumference at 90 days, according to the research . This means that high levels of insulin in the milk regulate the growth of babies and prevent them from getting overweight.
Finally, it should be noted that if a newborn has hypoglycemia, the feeding method should be carefully selected according to the actual health status of the baby.
Changes of Bioactive Components of Milk Reduce the Risk of Obesity in Newborns
The growth and development of infants are not only influenced by the three major milk energy substances (carbohydrate, fat and protein), but also affected by the bioactive components (leptin, adiponectin, growth hormone–releasing hormone (GHRH), obestatin, resistin, etc.) in breast milk .
Studies showed that both ghrelin and adiponectin are lower than normal level in colostrum and mature milk of women with GDM, while leptin levels are not significantly different. The level of adiponectin in colostrum and mature milk is negatively correlated with birth weight of newborn; The ratio of leptin or adiponectin is negatively correlated with weight and head circumference of newborn. The role of gastrin is to promote appetite and growth through interaction with hypothalamic receptors. Therefore, the decrease of ghrelin and adiponectin in breast milk of mothers with GDM will be beneficial to control the appetite of both mothers and infants, and prevent obesity.
In conclusion, it is recommended that mothers with GDM choose breastfeeding for at least 6 months, which is beneficial to regulate the growth and development as well as nutrition supply for the newborn.
 Qi Ruining, Li Limei, Chen Jing. The Research Progress on the Influential Factors and Promoting Measures of Breastfeeding in Parturient with Gestational Diabetes Mellitus at Home and Abroad [J]. Chinese Journal of Modern Nursing, 2019, 25 (20): 2632-2636
 Wei Kui, Gu Qingfang. Nutritional Characteristics of Lactose in Human Body [J]. Food Research and Development, 2012 (03): 195-197
 Sun Xiujing, Yu Xinting, Li Ming, et al. Levels of Ghrelin, Adiponectin, Leptin, and True Insulin in the Milk of Mothers with Gestational Diabetes Mellitus and Their Relationship to Infant Growth [J]. Chinese Journal of Perinatal Medicine, 2015 (4): 258-262
 Yu Xinting , Li Ming , Sun Xiujing , et al. The level of True Insulin in Breast Milk of Mothers with Gestational Diabetes Mellitus and Its Effect on Infant Growth [J]. Chinese Journal of Neonatology, 2011, 26 (3): 154-158
 Wang Wenling. Study on Milk Metabolomics in Women with Gestational Diabetes Mellitus and Its Influence on the Growth and Development of Their Offspring [D]