Hi Meegm,
I've been having BH from about 16 weeks. I asked my OB about it last week, and he said that it's early to be having them, but it is my second PG, so things are a bit more sensitive-and you feel more early on anyway. He also said that at my 19 week u/s, it was good that my cervix was nice and long, so he said everything seems fine.
I hope this helps,
Jess xo