Maturation signs of the cervix and prediction of preterm birth.

A prospective study was conducted on 7937 pregnancies, 4430 of which had prenatal visits before 37 weeks of gestation. Induced preterm deliveries were excluded (N = 40). Then the data was incorporated from the visits (cervix status, uterine contractions) as well as some common indicators of risk for preterm birth (mother's age, social status, obstetric antecedents, bleeding) into a predictive scoring system for spontaneous preterm labor. Different scores were computed according to both parity and to the timing during pregnancy when the signs were observed. It was found that approximatively 25% of the total preterm births were connected with the presence of at least one of three maturation signs of the uterine cervix (dilation of the internal os to 1 cm, cervical length less than 1 cm, and presence of painful uterine contractions).