[The cervix in primiparous women. A series of 320 perineal echographies].

Perineal ultrasound was carried out on a series of 320 primiparous women at their first antenatal visit. The results obtained show that an internal of that was larger than 20 mm was abnormal. A sign of a short cervix (less than 40 mm long on ultrasound) was of not much value but had to be taken notice of. In six cases it was found that clinically the cervix was absolutely normal and on ultrasound was incompetent.