According to this in the guardian
www.theguardian.com/lifeandstyle/2016/dec/30/women-suffer-much-more-work-stress-than-men-says-psychiatrist
Reasons given are balancing work and family, being disadvantaged by having to "prove" they are as good as men, not being promoted, being undervalued and increasingly the family being reliant on the woman's earning.
This is all depressingly familiar to me and I don't know what we do about it. Comments on this board show that many don't even believe it's an issue even in the face of evidence.