Does the decreased length of the cervix cause any complications?

Q: I am a 29 years old woman in the 6th month of pregnancy. It was noticed that the length of my cervix was below 3 cm. Does this cause any complications in my pregnancy? Why did the length decrease suddenly?

A:A length of 3 cms at about 6 months is close to normal, however, if there is any pain or spotting, a hospital visit to ensure that the labour is not starting may be needed. Also on the scanning, it is not only the length of the cervix, but the size of the internal os and anterior wall thickness of the lower segment, that is important to diagnose an incompetent cervix. If the internal os is closed, there is no cause for worry.