25th March 2011
Metformin is a drug used for type 2 diabetes that is increasingly used in pregnancy. While there is solid evidence it can be helpful in gestational diabetes, it is often prescribed in non diabetes settings “to help out”. A recent report (Journal of Clinical Endocrinology and Metabolism 95:5199-5202,2011) puts a bit of a dampner on this enthusiasm. In a prospective randomized control trial of 257 pregnant (five to twelve weeks gestation) women with polycystic ovarian syndrome the metformin did no better than the placebo in preventing pre-eclampsia or gestational diabetes. The only advantage was that pre term delivery was better in the metformin group which is good news as in the MiG study of metformin in gestational diabetes there were more pre term deliveries in the group taking metfomin.
Lead author Eszter Vanky says “Previous reports indicating a beneficial effect of Metformin in PCOS pregnancies have led to widespread use of the drug. Our study….speaks against this practice”. An interesting question of course is why the use of Metformin did not decrease the rate of gestational diabetes and the authors are at a loss to explain it. One possibility is that to diagnose GDM part of their criteria was a fasting glucose over 7 mmol/l, much higher than most would use, maybe they missed seeing some of the benefit in terms of lowering the fasting blood sugar.
New Studies Starting
What new research is going on in Type 2 diabetes in pregnancy?
In Canada a new study of using metformin in Type 2 diabetes is about to get under way. Led by Dr Denice Feig in Toronto the study involves many sites across the country. The primary endpoint is to see if using metformin in type 2 diabetes pregnant women reduces the bad outcomes for the baby. Further information is available from www.mity.ca