A longitudinal study of the cervix in pregnancy using transvaginal ultrasound

Abstract

Objective To study longitudinal changes in the cervix during pregnancy using transvaginal ultrasound and secondly, to determine whether the measures used change with gestational age, and whether there are differences between nulliparous and primiparous women. Design A longitudinal study involving five transvaginal ultrasound examinations of each woman at specified gestational ages from 18 to 30 weeks. Participants Twenty‐one nulliparous and 20 primiparous women completed the study and were delivered at term. Cervical length, diameter and dilatation were assessed at each examination. Results In both nulliparous and primiparous women there is no significant change in either cervical length or diameter over the time period studied. In primiparous women the cervix is significantly longer than in nulliparous women (44.4 (5.1) mm versus 40.6 (4.7) mm [mean (SD)]; P 0.001). The cervical diameter in primiparous women is also significantly greater (31.8 (4.0) mm versus 29.0 (3.7) mm; P < 0.001). Conclusions Cervical length and diameter are constant in both nulliparous and primiparous women throughout this gestational period. The cervix in primiparous women is both longer and thicker than in nulliparous women.

Relation of cervical length at 22-24 weeks of gestation to demographic characteristics and obstetric history

“…The present study has demonstrated that the mean cervical length of 37 mm was similar to that of other studies that measured cervical length at 20-24 weeks in low-risk populations in different settings (Table 6) (2,(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19).…”

Reference data representative of normal findings at two‐dimensional and three‐dimensional gray‐scale ultrasound examination of the cervix from 17 to 41 weeks' gestation

“…In all studies where cervical AP diameter was measured and compared between nulliparous and parous women it tended to be larger in parous women 17,18 , and in all studies AP diameter increased with gestational age 12,15,17,18 . This is in agreement with the present results.…”

“…Results of other studies are more variable: some found that cervical length did not change during pregnancy 12 , others found a continuous decrease from 10 to 40 weeks 13 or from 17 to 37 weeks 20 , while others still 14 reported that the cervix became longer between 8 and 25 weeks and then shortened. In most studies cervical length did not differ between nulliparous and parous women 13,14,20,28,29 , however in some the cervix was longer in parous women 17,18 . The discrepant results may be explained by differences in measurement technique, study design, the period in gestation studied, the statistical methods used, and the interpretation of the results.…”

“…The published studies cover different periods of gestation, have different study designs, and the study populations are mixed and/or small. There are only a few studies where reference values for cervical AP diameter 12,15,17,18 are presented, but to the best of our knowledge no reference values for cervical funneling have been published. In three small studies, cervical length 9,10,21 and funneling 9,10 were assessed by 3D ultrasound.…”

To Evaluate Efficacy of Sonographic Cervical Length to Predict Preterm Labour

“…[5] Cervical length is normally distributed and remains relatively constant in pregnancy until the third trimester. If there is any statistically significant reduction in length, it is not clinically significant (<0.5 mm /week) [6][7][8][9][10] . According to our study best cut off value for sonographic cervical length for predict Preterm delivery was 30 mm with Sensitivity and specificity 82.2% and 74%.…”