VAGINOSONOGRAPHY OF THE CERVIX IN TWIN PREGNANCIES

In a prospective study of 97 uncomplicated twin pregnancies, vaginosonographic cervix measurements of length, thickness and width of the internal os were performed. Furthermore, a group of 113 uncomplicated primipara was measured by vaginosonography. The twin pregnancies were examined sonographically at 4-5 week intervals between the 14th and 34th week of gestation. The results of the measurements were correlated between these two groups in accordance with duration of pregnancy and the number of deliveries. The results showed in general, that the cervical length of multipara-multiple pregnancy is longer than in the primipara-multiple pregnancy. Between the 13th and 17th week of gestation the cervix of primipara showed a length of 48.1+/-2.1 mm, the multipara twins showed a length of 52.3+/-3.4 mm. Between the 18th and 22nd gestational week, the primipara showed a cervical length of 49.4+/-3.6 mm and the multipara a length of 49.6+/-2.6 mm. In the 23th to 27th week, the primipara had a cervical length of 39.4+/-2.4 mm, the multipara of 49.3+/-3.7 mm. From the 28th to 33th week, cervical length was reduced in primipara to 31.2+/-2.9 mm, and in multipara to 42.7+/-5.1 mm. In the normal group of multipara, the cervical length was slightly longer. The assessment of cervical thickness showed the widest cervices in multipara gemini followed by the primipara gemini, the smallest cervices were found in primipara-single pregnancies. The measurements of the internal os of the cervical canal showed only slight differences in all groups, whereby the primipara-multi pregnancy had the widest opening of the internal os during the 28th - 33rd week of pregnancy, followed by multipara-multiple pregnancy. The smallest internal os was found in the multipara-single pregnancy group.