Mid-Trimester Endovaginal Sonography in Women at High Risk for Spontaneous Preterm Birth

Abstract

Cervical length assessed by endovaginal sonography between 16 weeks' and 18 weeks 6 days' gestation, augmented by serial evaluations, predicts spontaneous preterm birth before 35 weeks' gestation in high-risk women.

Use of transvaginal ultrasonography to predict preterm birth in women with a history of preterm birth

“…Interestingly, unlike most other studies of women with a history of spontaneous preterm birth20, 25–28, we noted the best cut‐off for cervical length to predict spontaneous preterm birth to be < 3.0 cm, rather than < 2.5 cm. This may be owing to the later gestational age at which transvaginal ultrasonography was carried out in our study, as most other studies evaluated cervical length prior to 24 weeks20, 25–28, with only one study evaluating cervical length after 24 weeks, in 42 women20. It is important that cervical length measured by transvaginal ultrasonography at this later gestational age be evaluated as many centers currently offer transvaginal ultrasound beyond 24 weeks of gestation to women with a history of spontaneous preterm birth29.…”

Assessment of obstetric history and cervical length as risk factors for preterm birth

“…In this study, CL was evaluated as a risk factor for preterm birth, adjusting the statistical analysis for other factors In the present study, 133 (9.7%) of the 1370 patients evaluated had preterm birth, defined as birth before 37 weeks. This finding is in agreement with the international literature regarding the incidence rate of this obstetric complication 4,8,10,11,[14][15][16][17][18][19][20] . In the systematic review of Crane 10 , the CL cutoff was 25 mm to predict preterm birth before 35 weeks, as determined by ultrasound at 20 weeks of gestation.…”

Clinical significance of cervical length shortening before 31 weeks' gestation assessed by longitudinal observation using transvaginal ultrasonography

“…Seven out of eight cases (87.5%) with a CL of <25 mm at ≤20 weeks' gestation were in the early CL shortening group, were at high risk for preterm labor and delivery, and received cervical cerclage and/or tocolysis later in pregnancy. This finding is compatible with other reports in which a CL of <20–25 mm at <20–24 weeks' gestation had a marked risk of preterm delivery, especially in high risk populations 5–8 …”