I experienced this also, and always ended up miscarrying. I was a DES daughter and the DES weaken my cervix causing it not to hold. My DR put in a cervical stitch in the cervix. This usually holds the cervix close. This did not work with me as the DES had really damaged me. He finally put in a permanent woven band around the outside of the cervix, which was attached to the ligaments to the uterus. I ended up carrying this pregnancy to 32 weeks. Spent 3 months on complete bed rest before hand. Had a healthy baby. This was 21 years ago. So if this continues, there are things they can do for you, if you do miscarry. My best wishes to you!