A Case Control Study of Diabetes During Pregnancy and Low Milk Supply

The objective of this study was to determine whether a history of diabetes during pregnancy, as a marker of perinatal glucose intolerance, increases the odds of a diagnosis of low milk supply at a Breastfeeding Medicine Clinic (BMC).

A case-control analysis was conducted of electronic medical records for BMC visits <90 days postpartum. Diabetes was defined as documentation of gestational, type 1, or type 2 diabetes. Cases were defined as those with a low milk supply diagnosis but without latch or nipple problems, and controls as those with latch or nipple problems but without low milk supply. A sensitivity analysis was then conducted by expanding cases to include all low milk supply diagnoses, and controls to include any diagnoses except low milk supply. Odds ratios (OR) and 95% confidence intervals (CI) for diabetes were calculated in cases versus controls, including adjustment for cesarean delivery, preterm birth, polycystic ovary syndrome, hypothyroidism, and infertility.

In the primary analysis, 14.9% of 175 cases versus 6.2% of 226 controls had a history of diabetes during pregnancy (OR 2.6 [95% CI 1.3-5.2]; adjusted OR 2.4 [95% CI 1.2-4.9]). In the sensitivity analysis, 14.9% of 249 cases versus 6.1% of 312 controls had diabetes in pregnancy (adjusted OR 2.4 [95% CI 1.4-4.3]).

Women diagnosed with low milk supply were significantly more likely to have had diabetes in pregnancy compared with women with latch or nipple problems and, more generally, compared with women with any other lactation difficulty. Further research is needed to elucidate how maternal glucose intolerance may impede lactation.