I went in last week for my 20 week ultrasound and found that my cervix was only 22mm, and was told to come back in a week to remeasure. I went in today and they found that I am now down to 15mm. I’ve been taking progesterone suppositories since my last appointment, but I’m finding it difficult not to worry about the safety of my twins as I am only at 21(nearly 22) weeks along... I go back in next week to look at the length again. Does anyone have experience with this? Any advice?