What Causes The Softening Of Cervix Without Opening?

I am 24 years old and my height is 165cm and weight aroubd 61. When i was in 8th month itself my cervix length got reduced and it was around 2.2cm. Doctor told cervix will be opened soon. So we need to avoid the premature baby and she has given Utodin tablet to avoid opening the cervix. Later during my due date cervix was soften fully but it was opened for only two fingers. And my baby had done potty inside. So Doctor advised to go for Emergency LSCS. I never wanted a C- section, but everyone convinced me and finally i agreed. Doctor told one in every 100 , will have this problem. Their cervix will be soften but not opened.

Is it true?

But what i am thinking is its due to that tablet doctor has given ?

Please advice.