Pregnancy in women with Type 2 diabetes: who takes metformin and what is the outcome?
OBJECTIVE
To review pregnancy outcomes in women with Type 2 diabetes (Type 2 DM), comparing women treated with those not treated with metformin.


METHODS
Data were collected by case-note review for all pregnancies in women with Type 2 DM over a 6-year period (1998-2003) at the National Women's Hospital. Two hundred and fourteen pregnancies were included, metformin was taken in 93 pregnancies and continued until delivery in 32; the remaining 121 pregnancies comprised the control group. The principal outcome measures were preeclampsia, perinatal loss and neonatal morbidity.


RESULTS
Baseline characteristics differed between groups: women in the metformin group had greater mean (SD) body mass index [35.5(7.6) vs. 33.5(6.6) kg/m2, P < 0.05], more chronic hypertension (19% vs. 7%, P < 0.05) and higher mean (SD) first trimester glycated haemoglobin (HbA1c) levels [8.3(1.9)% vs. 7.5(1.7)%, P < 0.005]. There was no difference between metformin and control groups, respectively, in the rate of preeclampsia (13% vs. 14%, P = 0.84), perinatal loss (3% vs. 2%, P = 0.65) or neonatal morbidity, including rate of prematurity (23% vs. 22%, P = 0.7), admission to the neonatal unit (40% vs. 48%, P = 0.27), respiratory distress (9% vs. 18%, P = 0.07) and treatment with intravenous dextrose (20% vs. 31%, P = 0.08).


CONCLUSIONS
Pregnant women with Type 2 DM who were treated with metformin had more risk factors for adverse pregnancy outcomes, but no differences in outcomes were seen compared with women not taking metformin. We need randomized trials to address potential benefits of metformin treatment in this population that may be masked by current practice.
Department of Medicine, Auckland, New Zealand. jrowan@internet.co.nz
R C E
RC
Hughes
J A
JA
Rowan
D000328:Adult; D015992:Body Mass Index; D002908:Chronic Disease; D036861:Delivery, Obstetric; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000453:epidemiology; D005260:Female; D046689:Fetal Mortality; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases / Q000453:epidemiology; D008485:Medical Audit; D008687:Metformin / Q000627:therapeutic use*; D009520:New Zealand / Q000453:epidemiology; D011225:Pre-Eclampsia / Q000453:epidemiology; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000453:epidemiology; D011256:Pregnancy Outcome / Q000453:epidemiology; D011254:Pregnancy in Diabetics / Q000188:drug therapy* / Q000453:epidemiology
D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D008687:Metformin