Correlation between Transperineal and Transvaginal Sonography in Cervical Length Measurement among Normal Thai Pregnant Women at 16 to 24 Weeks of Gestation
Ekachai Kovavisarach MD*,**, Rujirek Kedthong MD**
Affiliation : * Department of Obstetrics and Gynecology, Rajavithi Hospital, College of Medicine, Rangsit University, Bangkok, Thailand ** Department of Obstetrics and Gynecology, Rajavithi Hospital, Bangkok, Thailand
Background : Currently, cervical length is generally measured by transvaginal sonography (TVS) to predict preterm labor.
Transperineal sonography (TPS) has been proposed as an alternative modality to TVS.
Objective : To compare cervical length measurements and pain scores of TPS and TVS in normal Thai pregnant women
Material and Method: A total of 40 normal Thai pregnant singleton women were enrolled at the antenatal clinic, Rajavithi
Hospital between 1st December 2014 and 28th February 2015 at 16 to 24 weeks of gestation. Patients were excluded if they had
history of and proved rupture of membranes, body mass index (BMI) >30 kg/m2, antepartum hemorrhage, or mass at
perineum. The TPS and TVS techniques for cervical length measurement were performed in all cases by a single researcher
(RK). Visual analog scale (VAS) score was used to assess the pain score (total = 10).
Results : Mean cervical lengths measured by TVS were slightly greater than those found using TPS (37.80 mm and 35.73 mm,
respectively). The Pearson’s correlation coefficient between the two methods was 0.746, p<0.01. Mean pain scores determined
by VAS score in TPS and TVS were 0.15 and 0.03, respectively (p = 0.02). The number of people whose VAS score was zero
was similar with both methods (87.2% and 71.8%, respectively) (p = 0.095).
Conclusion : TPS could be used as an alternative method of TVS to assess CL in normal Thai pregnant women at 16 to 24
weeks of gestation because of its good correlation coefficient and lower pain levels.
Keywords : Cervical length, Transperineal sonography, Transvaginal sonography
