A couple of weeks ago, I wrote a piece on the possible impacts of metformin on sperm, highlighting what I thought was an excellent paper raising concerns about the link between this diabetes treatment in men and birth defects. In response, a number of people asked about metformin in women. One reason is its use in treating diabetes, as it is used in men. But beyond diabetes, metformin is also often prescribed for infertility.

So today, a quick follow-up on this question. The TL;DR is that we do not see this same set of birth defect concerns, although the evidence on the efficacy of metformin for treating infertility is also fairly weak.