Uterocervical angle as a predictor for spontaneous singleton preterm birth: a prospective observational study

Area of Science:

• Obstetrics and Gynecology
• Medical Imaging
• Perinatal Medicine

Background:

• Cervical length (CL) has limited performance in predicting spontaneous preterm birth (sPTB) in Thailand due to low short cervix prevalence.
• The uterocervical angle (UCA) is explored as an alternative predictor for sPTB.

Purpose of the Study:

• To evaluate the diagnostic performance of UCA compared to CL for predicting sPTB.
• To assess the combined diagnostic performance of UCA, CL, and cervical wedging for sPTB prediction.

Main Methods:

• Prospective cohort study of singleton pregnancies between 16-24 weeks gestation.
• Transvaginal ultrasonography used to measure UCA and CL.
• Primary outcome: diagnostic performance of UCA and its integration with other parameters for sPTB before 37 and 34 weeks.

Main Results:

• UCA cut-offs of 85° (before 37 weeks) and 95° (before 34 weeks) were identified.
• CL under 30mm demonstrated better prediction for sPTB before 34 weeks (AUC 0.71) than UCA over 95° (AUC 0.66).
• Integration of UCA with CL or cervical wedging did not improve prediction over CL alone.

Conclusions:

• A wider UCA is associated with increased sPTB risk.
• UCA alone has lower diagnostic performance than CL or cervical wedging for sPTB prediction.
• CL remains a more effective predictor than UCA for sPTB before 37 weeks.