I had the doctor tell me my baby had that but when I went back for another ultrasound it was gone. I was freaked out too but it's very unlikely for that to cause any problems and they usually resolve on their own before baby is born.

I have a bicornuate uterus so I have to different horns my baby is growing in my right horn and I have a cyst in my left horn so far everything is good there really is nothing to worry about they come and they go it's the joys of being a girl I can say. but I heard when they do pop that it will hurt super bad it's a cramp like feeling.