VP46.12: The value of cervical ultrasound in the threatened preterm labour

Abstract

Purpose of the work is to evaluate the relevance of measuring cervical length by transvaginal ultrasound to assess the risk of spontaneous prematurity in the event of a threat of preterm birth and its contribution to the indication of emergency hospitalisation. This is a prospective study of 100 patients presenting threatened preterm labour between 24–36 weeks of gestation, having undergone cervical assessment by ultrasound, collected at the maternity and neonatal centre of Tunis during a period of 12 months from May 2017 to May 2018. The average age is 29 years old. 59% are primiparous. 55 patients have a cervical length ≤25mm. Ultrasound measurement of the cervical length, with a threshold at 25mm, has a sensitivity of 100% and 92% to predict respectively the occurrence of a delivery at 48H and seven days. The specificity is respectively 53% and 58%. The positive likelihood ratio is estimated at 2.15 and 2.2, respectively. The Baumgarten score≥ 4 has a positive likelihood ratio similar to ultrasound but a significantly lower sensitivity. The presence of membrane protrusion has a positive likelihood ratio estimated at 2.75 and 4.15 to predict the onset of delivery at 48H and at seven days, respectively, but with a sensitivity of 68% and 73%. The measurement of the opening of the cervical internal orifice ≥ 5mm seems of little use with a positive likelihood ratio of 0.85 and 0.79. Cervical length measurement by transvaginal ultrasound with a threshold at 25mm facilitates the identification of women at risk of preterm delivery and thus the selection of those who could benefit from specific care.