Cervical Length During Pregnancy in Korean Women as Assessed by Transvaginal Ultrasound: A Prospective Longitudinal Study

Yang, Soon Ha; Choi, Seong Jin

Abstract

OBJECTIVE
The aims of this study are to evaluate the longitudinal change in the cervix throughout pregnancy by transvaginal ultrasound and to establish a normogram of the cervical length in Korean pregnant women.
METHODS
A prospective observational study was undertaken. Forty-eight women of singleton pregnancy without history of preterm delivery and medical or obstetrical complication were finally enrolled. Serial transvaginal ultrasound examination and the measurement of cervical length were performed at 12 weeks of gestation and every 4 weeks (until 28 weeks), every two weeks (until 36 weeks) and every week until delivery. ANOVA for repeated measures and paired t test were used for statistical analysis.
RESULTS
The mean gestational age at delivery was 39.9 weeks. There was a significant quadratic correlation between gestational age and cervical length (y=-0.0038x(2)+0.1773x+1.6437, p<0.001). The cervical length was gradually increased until 24 weeks of gestation and then decreased during rest period of gestation. The measured values were distributed normally at each gestational age and the normogram of cervical length during pregnancy was presented in term of mean and standard deviation. There was no significant difference in cervical length between primipara and multipara.
CONCLUSION
We presented serial measurements of cervical length throughout normal pregnancy. These values can be used as normative guidelines in assessment of cervical length during pregnancy.