I took it when I was 39 weeks pregnant. The midwives suggested it when I was about 36 weeks along, but it took us that long to find it, no place in town had it in stock. I was also a vbac, and was not "allowed" to go past 41 weeks. I also started taking epo at 35 weeks. The only problem I had with it was the nasty taste of the pills, the capsule started to melt as soon as I put it in my mouth, horrible, horrible taste.