engleski

Screening for preterm labor in low risk population. Clinical examination vs. transvaginal ultrasound

Objective: To compare the diagnostic performance of transvaginal ultrasonographic (TVS) and digital examination of the cervix at mid trimester in the prediction of preterm delivery in low risk pregnancy. Study design: Prospective randomized study of 118 unselected, asymptomatic, women with singleton pregnancies randomly underwent TVS cervical length measurement (n=58) or digital examination (n=60) at 16-24 weeks' gestation as screening tests for preterm delivery (PTD). Cervical parameters evaluated with TVS included endocervical length, internal axis width, presence of cervical mucus and cervical glands area. Parameters evaluated with digital examination were cervical dilatation and effacement. Primary outcome variable was the occurrence of preterm delivery (< 37 weeks) and secondary outcomes included perinatal morbidity, perinatal mortality, IUGR, type of delivery, weeks at delivery, and tocolysis therapy (iv. and per os). Results: The prevalence of preterm delivery was 5.93% (7/118). Abnormal finding in TVS group was found in 2/58 (endocervical length < 20 mm) whereas in digital examination group in 9/60 (cervical dilatation and effacement). The median time of examination between two groups was similar (20.05 weeks vs. 20.4 weeks). In TVS group there were no differences in cervical length among subgroups with positive and negative glandular area but in subgroup where cervical mucus is positive the cervical length was longer (38.652mm vs. 30.916mm). Tocolysis therapy was frequently in digital examination group (12/60 vs. 6/58), because the abnormal finding which was the major indication for tocolysis was oftness in this group (tocolysis after abnormal finding 6/12 vs. 1/6). There were no other statistical differences in outcomes between two groups. As a potential screening test for preterm delivery TVS had better sensitivity, specificity, positive and negative predictive values than digital examination (the sensitivity, specificity, positive predictive value, and negative predictive value of TVS were, respectively, 66.66, 100, 100, and 98.27% and at digital examination they were 25, 86.44, 11.11, and 94.12%). Conclusion: TVS of the cervix in patients at low risk for preterm birth provides an objective method for evaluating the risk of preterm delivery.

pregnancy; preterm delivery; screening

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