Is transvaginal ultrasonography at mid-trimester useful for predicting early spontaneous preterm birth?

Numerous reports have examined the relationship between sonographically determined cervical length and spontaneous preterm birth. Moreover, large screening studies have consistently demonstrated that the shorter the cervical length, the higher the rate of spontaneous preterm delivery. However, the sensitivity and positive predictive value of the cervical length for detecting preterm birth were low. Subsequently, we developed a new sonographic parameter termed "cervical gland area (CGA)". The purpose of this study was to determine whether sonographic cervical findings (shortened cervical length or absence of CGA) at 16 - 19 weeks' gestation could predict spontaneous preterm birth. The absence of CGA as compared to the shortened cervical length showed a higher sensitivity (75.0% vs. 50.0%) and a significantly elevated positive predictive value (54.5% vs. 8.3%) for preterm birth before 32 weeks' gestation. It was concluded that the absence of CGA was a novel and useful sonographic parameter for predicting early spontaneous preterm birth.