A longitudinal follow-up of cervical length during pregnancy

A prospective longitudinal study of cervical length during pregnancy included 60 women. Three groups of patients were analyzed: group I--cervical length was measured in all three trimesters, group II--cervical length was measured in the first and second trimesters, and group III--length was measured in the second and third trimesters. Cervical length was measured in each group individually, with the aim of establishing the trend of change. In the group in which the cervical length was measured in all three timesters, there was either a mild progressive cervical shortening or cervix remained of the same length. The number of examined women is very small, though, so more valid is the information that the trend of mild shortening occurs in the second and third trimesters. None of the trends is particulary explicit and shows that there is a period in an uncomplicated singleton pregnancy of low risk for preterm delivery, during which there is a significant shortening before delivery takes place. During pregnancy there are different, individual modes of cervical changes, which leads to individualization when estimating the risk for preterm delivery. Reference values should be established for cervical length in order to assess risk for preterm delivery, rather than use the "cut-off" value after which the risk is considered higher.