Metformin ineffective for IVF

Metformin (Glucophage) is a commonly used treatment for polycystic ovary syndrome (PCOS) . Metformin is used to treat insulin resistance which is commonly found in women with PCOS. There is sufficient data currently to state that metformin use in PCOS patients can result in ovulation and thus increased fertility in PCOS patients. More recently, metformin has been lauded as a means to “make eggs stronger” and thus improve the chances for pregnancy, reduce the risk for miscarriage, increase the number of eggs retrieved during IVF cycles, and a host of other “miracles”. Unlike the case of inducing ovulation, there is little if any data to support these other assertions.

In the first study on the effects of metformin on IVF cycles in PCOS, the outcomes of 60 women who took metformin were compared to women who did not take metformin. The study authors concluded that metformin might improve IVF outcomes in PCOS patients. In another study, only 17 women with PCOS who were undergoing in vitro fertilization were studies. That study concluded that the number of eggs retrieved could be increased without increasing the dose of medication taken. On the other hand, another study comparing in vitro fertilization patients did not find any difference between those who took metformin and those who did not.

Recently, a much larger study of 108 PCOS patients was conducted. The study size and design were superior to the previous studies reported.

PCOS patients were split into two groups. One group received metformin (53 women) and the other group received a placebo (55 women). Neither the doctors nor the patients knew who was receiving the real metformin. The PCOS patients then proceeded with an in vitro fertilization cycle.

There were no differences between the two groups in any of the following categories:

  • Baseline characteristics
  • Duration of time that fertility drugs were given
  • The total dose of fertility drugs used
  • The number of follicles which developed
  • The number of eggs that were retrieved
  • The fertilization rate
  • The number of embryos the doctors were able to replace
  • Or
  • The pregnancy rate

Patients with laboratory evidence of insulin resistance had similar measures of outcome in both placebo and metformin groups.
Based on the available evidence, it would seem that using metformin for in vitro fertilization cycles is of no benefit.