Poster Topical Area: Maternal, Perinatal and Pediatric Nutrition
Location: Hall D
Poster Board Number: 349
Objectives: Emerging clinical research is corroborating an important role for healthy insulin action in lactation. Metformin is a first-line drug for improving insulin action and is considered safe to use during lactation, but it has never been tested for efficacy in treating low milk supply. Our objective was to conduct a preliminary randomized clinical trial (RCT) of metformin versus placebo in women with low milk production and signs of insulin resistance.
Methods: RCT inclusion criteria included: mother 1-8 weeks postpartum, low milk production based on 24-hour test weighing, and ≥ 1 insulin resistance sign; with a singleton, healthy term infant. Exclusion criteria included identified cause of low milk supply or contraindication to metformin. Eligible mothers were randomly assigned 2:1 to metformin or placebo. Mothers received a hospital-grade pump and were instructed to augment breastfeeding >8 times/day with breast pumping. Milk production was remeasured 2 and 4 weeks post-intervention.
Results: 51 women were screened and 15 met RCT eligibility. Median values at baseline in metformin (n=10) versus placebo (n=5), respectively, were: maternal age (33 versus 36 years), body mass index (37.5 versus 39.7 kg/m2), gestational diabetes (60% versus 20%), infant age (20 versus 40 days), breast emptying (18 versus 15 times/day) and milk output (148 versus 266 grams/day). Milk output improved in 6/10 metformin (60%) versus 1/5 placebo (20%, Fisher's exact P-value=0.28). Median change from baseline was 8 versus -56 grams, respectively (Wilcoxon P-value, 0.30).
Conclusions: A trend toward greater improvement in the metformin group was mostly due to overall worsening of milk production in the placebo group, despite aggressive pumping and lactation support. More work is needed to develop interventions for metabolically at-risk mothers with low milk supply.
Associate Professor of Nutritional Sciences
University of Cincinnati College of Allied Health Sciences