Predicting Spontaneous Preterm Birth: A Prospective Study of Uterocervical Angle and Cervical Length Assessment through Transvaginal Sonography

  • Naushaba Malik Consultant Radiologist, PESSI Hospital, Islamabad.
  • Shah Bakht Aftab Post Graduate Surgery Resident, PIMS, Islamabad.
  • Rida Noor Post Graduate Surgery Resident, PIMS, ISLAMABAD.
  • Sara Jamil Khan Obstetrics and Gynaecology RHQ Chilas
  • Noor Aftab Pakistan Institute of Medical Sciences, Islamabad
  • Minaal Ahmed Malik PIMS, Islamabad.
Keywords: Premature Birth


Objectives: This study uses transvaginal ultrasound (TVS) in the second trimester to measure both AUCA and cervical length (CL) to see if either can predict spontaneous preterm labor.

Methodology: This prospective study was conducted at the department of Radiology, PESSI Islamabad from April 2023 to December 2023. The departmental Ethics committee approved the study. 140 first-time pregnant women (primigravidas) carrying a single baby (singleton) with no complications during their pregnancy. Between 16 and 24 weeks, a transvaginal ultrasound (TVS) was performed to measure the angle of the uterus where it meets the cervix (anterior uterocervical angle, UCA) and the length of the cervix (CL). The women were monitored until they gave birth to record their gestational age at delivery.

Results: Out of the 140 pregnant women who met the criteria and joined the study, 40 women delivered preterm (sPTBs), 22 of these women had cesarean sections after going into labor and 18 women had normal vaginal deliveries. Similarly, 100 women delivered at full term, 16 of these women had cesarean sections and rest of the 84 women had normal vaginal deliveries. On average, the women in the preterm birth group delivered their babies at 34.8 weeks’ gestation. The study found a connection between a wider UCA in the second trimester and a higher chance of preterm birth (PTB) before 37 weeks. Among 140 women, 42 had a UCA wider than 95 degrees. Out of these 42 women, 34 delivered preterm. Out of 140 women, 20 had a CL shorter than 2.5 cm. Among them, 16 delivered preterm, while only 4 delivered at term. Women with a CL less than 2.5 cm had a much higher rate of preterm birth compared to those with a CL of 2.5 cm or more.

Conclusion: The study found a new way to measure risk of preterm birth using ultrasound. This method, called the uterocervical angle (UCA), seems to be more accurate than the traditional method of measuring cervical length (CL). There's a strong link between a wider UCA angle (obtuse UCA) and a higher chance of having a spontaneous preterm birth.

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