Latency period Archives - Revista Brasileira de Ginecologia e Obstetrícia

PURPOSE: to assess the length of the uterine cervix by transvaginal ultrasonography in pregnant women with preterm premature rupture of membranes. METHODS: the study group (Ge) consisted of 26 pregnant women with gestational age between 24 and 36 weeks and the control group (Gc) of 49 clinically normal patients at the same gestational age. The patients were evaluated between the 24th to 28th, 28th to 32th and 32th to 36th weeks. The groups were divided into subgroups Ge24-28, Ge28-32, Ge32-36 and Gc24-28, Gc28-32, Gc32-36, according to the study or control group. The cervix length was measured by transvaginal ultrasonography as the linear distance between the internal and external cervical os. RESULTS: we observed significant differences in cervix length between Ge24-28 and Gc24-28 groups whose values were, respectively, 24.3 and 33.0 mm (p=0.04), and between Ge32-36 and Gc32-36, 20.1 and 28.0 mm, respectively (p=0.005). The latency periods of Ge24-28, Ge28-32 and Ge32-36 were, respectively, seven, five and three days, showing a positive correlation with cervix length (r=0.66) and a negative correlation with gestational age (r=-0.27). CONCLUSIONS: the length of the uterine cervix varied with the gestational age when premature preterm rupture of the membranes was detected, with the length being shorter in the study group than in the control group betweeen the 24th and 28th and 32th and 36th weeks. In addition, it was demonstrated that, the shorter the cervix length, the shorter the latency time, with a reduction in the latency period with increasing gestational age at the time of rupture.