title: Metformin versus insulin in gestational diabetes mellitus: a meta-analysis of randomized clinical trials.
abstract: BACKGROUND
  Metformin is widely used in treatment of type 2 diabetes. However, whether it is safe for use in pregnancy is controversial.
  
  
  METHODS
  A search for relevant studies were performed using PubMed (1948-2014), Embase (1974-2014), the Web of knowledge (1950-2014), and the Cochrane database, included all randomized control trials published in English.
  
  
  RESULTS
  Eight RCTs (1712 patients with gestational diabetes mellitus) were retrieved; of those 853 patients were given metformin, and 859 patients were given insulin. Our results showed that metformin does not increase risk of prematurity (RR = 1.26; 95 % CI [0.89, 1.79], P = 0.19). In addition, metformin can either decrease the total weight gain [MD = -1.49, 95 % CI (-2.66, -0.31), P = 0.01] or weight gain after randomization [MD = -1.23, 95 % CI (-1.75, -0.71), P < 0.00001]. No significant differences were observed in patients with pre-eclampsia [RR = 0.82, 95 % CI (0.56, 1.2), P = 0.32] or caesarean section [RR = 0.93, 95 % CI (0.75, 1.16), P = 0.53]. Use of metformin also significantly decreased the risk of neonatal hypoglycemia [RR = 0.58, 95 % CI (0.43, 0.78), P = 0.0003] and admission rates to neonatal intensive care units [RR = 0.74, 95 % CI (0.61, 0.89), P = 0.002]. No other adverse effects were observed, such as hyperbilirubinaemia [RR = 0.83, 95 % CI (0.64, 1.08), P = 0.16], large for gestational age [RR = 0.85, 95 % CI (0.68, 1.05), P = 0.14], small for gestational age [RR = 0.92, 95 % CI (0.61, 1.39), P = 0.69], macrosomia [RR = 0.75, 95 % CI (0.54, 1.03), P = 0.07] or respiratory distress syndrome [RR = 0.88, 95 % CI (0.55, 1.41), P = 0.6].
  
  
  CONCLUSIONS
  Metformin may be beneficial in treating gestational diabetes. However, even more studies are needed to provide more evidence for the future use of metformin.
authors: Beijing Tian Tan Hospital, Capital Medical University, Beijing, China.
authors: B
authors: B
authors: Zhu
authors: Beijing Shijitan Hospital, Capital Medical University, Beijing, China.
authors: L
authors: L
authors: Zhang
authors: Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors: Y Y
authors: YY
authors: Fan
authors: The Third Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China.
authors: L
authors: L
authors: Wang
authors: Beijing Tian Tan Hospital, Capital Medical University, Beijing, China.
authors: X G
authors: XG
authors: Li
authors: Beijing Tian Tan Hospital, Capital Medical University, Beijing, China.
authors: T
authors: T
authors: Liu
authors: Dong Fang Hospital-The Second Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China.
authors: Y S
authors: YS
authors: Cao
authors: Beijing Tian Tan Hospital, Capital Medical University, Beijing, China. 174473712@qq.com.
authors: Z G
authors: ZG
authors: Zhao
mesh_terms: D001724:Birth Weight; D002585:Cesarean Section; D016640:Diabetes, Gestational / Q000453:epidemiology*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007328:Insulin / Q000627:therapeutic use*; D008687:Metformin / Q000627:therapeutic use*; D011225:Pre-Eclampsia / Q000453:epidemiology; D011247:Pregnancy; D016032:Randomized Controlled Trials as Topic
chemical_list: D007328:Insulin; D008687:Metformin
keywords: Gestational diabetes mellitus; Insulin; Metformin; Randomized control trials