I had this with my second pregnancy. I was seeing my consultant at the hospital due to my high bp and she decided to scan me to check babies growth. This was at 38wks. They noticed I had far to much fluid around her. The actual name for this begins with a p I think (baby brain) and they decided to monitor me. Well I started to bleed at 39wks and I went into hospital and I was 7cms and I didn't even feel I was in labour. They said they wanted to break my waters as they wanted to be able to control the flow and oh my was there some water. Tones and tones and tones. She had to put her hand in to control it. Once my waters had gone my baby girl was out in a matter of minutes. It all happened so quick. The bleed was from the placenta due to the pressure of the water on it. At 38wks I was measuring 42wks and it was only luck I got scanned then as no one would of known. I had shortness of breath and just so uncomfortable leading up to this scan. But due to my son being 8lb 14 all the midwifes thought I was just having another big baby. My daughter weighed 7lb 2. Its good that they are keeping an eye on you x