Hi Natasha,
Sorry you are going through such a hard time.
Reasons behind pre-term labor are largely unknown. As they do not know what causes it, doctors cannot be sure of the treatment. Bed rest may help and may not help.
Short cervix, on the other hand, is a different issue. Bed rest, to a point, will decrease the weight forced upon the cervix which may help further shortening and funnelling.
I had my daughter in 2010, full term. Today I am 37 years old, 33 weeks pregnant with short cervix. At 20 week ultrasound, I was diagnosed with short cervix and asked to be on bed rest. I had few more ultrasounds to check the length. It varied between 1.7-2.1 cm at 20-21 weeks when it is suspposed to be 4-5 cm.
I have been on bed rest since. I did not have any contractions or bleeding. Today marks the 3 month completion of bed rest for me.
I cannot offer any medical advice though but please try to take it easy. Drink lots of water. Dehydration can cause contractions.
Nothing is 100% sure. All pregnant women are at risk of pre-term labor. Most women who experience pre-term labor go to deliver full-term. My doctor said about the short cervix is not a good measure of pre-term labor. It increases the risk for sure but it is not guaranteed that the woman with short cervix will deliver early.
Check with your doctor about the length of the cervix. Are you still on progesterone?
Do keep us updated. Best of luck!!