Uterine contractions in asymptomatic pregnant women with a short cervix on ultrasound

Objective. To estimate the incidence of uterine contractions in asymptomatic pregnant women with a short cervix on transvaginal ultrasound. Methods. Asymptomatic women with a short cervix on transvaginal ultrasound between 14 and 23^6/7 weeks of pregnancy were instructed to undergo uterine monitoring immediately. Women without available tracings were excluded. Women with and without contractions were compared with regard to demographics, risk factors, and outcomes. Results. One hundred and one women with a short cervix and available tracings were identified. Eighty-six (85%) had contractions and 15 (15%) did not have contractions immediately after identification of the short cervix. The median number of contractions per hour per woman was 4 (range 0-31). These two groups did not differ in demographics, risk factors, or outcomes, except for the fact that 33% of women with contractions versus 73% of women without uterine contractions had a prior second trimester loss (p = 0.004). Conclusions. In this study, 85% percent of pregnant women with a short cervix on transvaginal ultrasound between 14 and 24 weeks of pregnancy are having asymptomatic uterine contractions. This information is important for further investigation of the short cervix and preterm delivery.