thanks Nazeema and Sonali...

The cervix is the mouth of the uterus at the vaginal end. During pregnancy it is long and thick and tightly closed. The minimum is expected to be 2.5 as long as the internal os is closed and it is not reducing as a pattern. A 4.1 is normal.

It's usually 4.1-4.2. In that case it's normal

thanks

yes it's alright. The length of cervix is measured on ultrasound and also to see if it's closed as is the case normally. A short or open cervix can lead to a preterm delivery hence the need to check it.