RESUMO
This study was aimed to establish reference values of cervical length in normal pregnancy. We studied a cross-sectional sample of 144 pregnant women by transabdominal sonography. The inclusion criteria were sonographic confirmation of gestational age; the absence of any risk factors for preterm birth; and uncomplicated pregnancy. Cervical length was measured in a straight line. Height; age and weight of patients were also obtained. There was a relationship between gestational age and cervical length; which could be described with a linear regression (R = 0.44; P0.05). Our study shows an increase in cervical length with gestational age. Reference ranges constructed for the whole gestational period could be more clinically applicable and useful than a single cut off value for more efficient prevention and management of preterm birth
