I had my son six weeks ago and starting around 28 weeks, I had BH constantly. I mean, I could have ten in like a half hour easily. My doctor told me that some women are more prone to them than others and not to worry about it unless I can't talk through them. Your uterus is preparing itself for birth. I worried about it, too, but when I went into labor I realized that there is a HUGE difference between BH and regular contractions. If your doctor isn't worried, I wouldn't be either.