title: The effects of metformin on weight loss in women with gestational diabetes: a pilot randomized, placebo-controlled trial.
abstract: OBJECTIVE
  We sought to compare weight loss in the first 6 weeks postpartum among women with gestational diabetes mellitus (GDM) treated with metformin or placebo, a promising therapy to reduce later risk of progression to diabetes mellitus.
  
  
  METHODS
  We conducted a pilot, randomized trial of metformin vs placebo in postpartum women with GDM. Women with pre-GDM, unable to tolerate metformin, resumed on insulin or oral hypoglycemic agent, delivered <34 weeks' gestation, or with a body mass index <20 kg/m(2) were excluded. Women were randomized to either metformin 850 mg daily for 7 days, then metformin 850 mg twice a day for the next 5 weeks or placebo prescribed in a similar frequency. The subject, health care provider, and research staff were blinded to the treatment. The primary outcome was weight change from delivery to 6 weeks postpartum. Secondary outcomes included the percentage of women achieving their self-reported prepregnancy weight, reported medication adherence, adverse effects, and satisfaction. Differences in weight change between groups were determined by Wilcoxon rank sum test and in achieving prepregnancy weight by χ(2) test.
  
  
  RESULTS
  Of 114 women randomized, 79 (69.3%) completed the 6 weeks; 36 (45.6%) were randomized to metformin and 43 (54.4%) to placebo. Metformin and placebo groups were similar in median weight loss (6.3 kg [range, -0.3 to 19.8] vs 6.5 kg [range, -0.3 to 12.1], P = .988) and percentage of women achieving reported prepregnancy weight (41.7 vs 37.2%, P = .69). Self-reported adherence in taking >50% of medication was 75% at 3 weeks and 97% at 6 weeks. Nausea, diarrhea, and hypoglycemia were reported in approximately 11-17% of women and 56-63% reported dissatisfaction with the medication.
  
  
  CONCLUSIONS
  Women with GDM lost approximately 6 kg by 6 weeks' postpartum. This was similar in both groups and resulted in <50% of women achieving their prepregnancy weight. Although the reported adherence and satisfaction with the medication was high, adverse effects were reported with nearly 1 in 5 women including nausea, diarrhea, and hypoglycemia. Contrary to expectation, we found no evidence of benefit from metformin. However, longer treatment periods and larger studies with minimal attrition may be warranted.
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Texas Health Science Center at Houston, Houston, TX. Electronic address: Jerrie.S.Refuerzo@uth.tmc.edu.
authors.forename: Jerrie S
authors.initials: JS
authors.lastname: Refuerzo
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Texas Health Science Center at Houston, Houston, TX.
authors.forename: Oscar A
authors.initials: OA
authors.lastname: Viteri
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Texas Health Science Center at Houston, Houston, TX.
authors.forename: Maria
authors.initials: M
authors.lastname: Hutchinson
authors.affiliation: Center for Clinical Research and Evidence-Based Medicine, Division of Neonatology, Department of Pediatrics, University of Texas Health Science Center at Houston, Houston, TX.
authors.forename: Claudia
authors.initials: C
authors.lastname: Pedroza
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Texas Health Science Center at Houston, Houston, TX.
authors.forename: Sean C
authors.initials: SC
authors.lastname: Blackwell
authors.affiliation: Center for Clinical Research and Evidence-Based Medicine, Division of Neonatology, Department of Pediatrics, University of Texas Health Science Center at Houston, Houston, TX.
authors.forename: Jon E
authors.initials: JE
authors.lastname: Tyson
authors.affiliation: Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, Baylor College of Medicine, Houston, TX.
authors.forename: Susan M
authors.initials: SM
authors.lastname: Ramin
mesh_terms: D000293:Adolescent; D000328:Adult; D016640:Diabetes, Gestational / Q000188:drug therapy*; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D057194:Intention to Treat Analysis; D008687:Metformin / Q000494:pharmacology* / Q000627:therapeutic use; D008875:Middle Aged; D017060:Patient Satisfaction / Q000706:statistics & numerical data; D010865:Pilot Projects; D011181:Postnatal Care / Q000379:methods*; D011247:Pregnancy; D016896:Treatment Outcome; D015431:Weight Loss / Q000187:drug effects*; D055815:Young Adult; D016903:Drug Monitoring
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin
keywords: gestational diabetes; metformin; weight loss