Early prediction of preterm delivery by transvaginal ultrasonography

Abstract

The clinical value of transvaginal ultrasonography in the evaluation of the uterine cervix of pregnant women was studied. Comparison with conventional transabdominal ultrasound in 24 pregnant subjects revealed that transvaginal ultrasound was superior, because the transabdominal technique usually requires a full bladder, which causes deformation and elongation of the cervix. Digital examination showed dilatation of the internal os in only ten (38.5%) of 26 patients in whom it had previously been shown by transvaginal sonography. Transvaginal ultrasonography has the advantage of providing natural and objective information on the cervix. The values of three sonographic signs found transvaginally for predicting preterm delivery were evaluated in a total of 130 at-risk patients and 129 control subjects. Shortening of the cervical length by -1.5 SD or more was associated with an increased risk of preterm delivery (11.3% vs. 2.8%, p < 0.01). A dilated internal os of more than 5 mm before 30 weeks of gestation was associated with preterm delivery more often than an undilated internal os (33.3% vs. 3.5%, p < 0.01). Dynamic changes in the degree of dilatation of the cervical canal which were found in nine women were significantly related with preterm delivery (p < 0.05). But, in the at-risk group, only dilatation of the internal os had a predictive value for preterm birth. From these data, dilatation of the internal os on transvaginal ultrasonography was proved to be an early and important predictor of preterm delivery.

The cytokine network in women with an asymptomatic short cervix and the risk of preterm delivery

“…17–21,23–27,30,61,62 Additionally, Moroz and Simhan 221 reported a significant association between cervical shortening and maternal systemic inflammation (determined by C-reactive protein; r 2 =.44, P =.001) in women with a sonographic short cervix (≤25 mm) diagnosed between 21 and 28 weeks of gestation. However, this association was not observed in patients without a short cervix.…”

Vaginal progesterone vs cervical cerclage for the prevention of preterm birth in women with a sonographic short cervix, previous preterm birth, and singleton gestation: a systematic review and indirect comparison metaanalysis

“…67–74,116–122 It is unlikely that this condition is due to a single cause, and a multiple causation model of a sonographic short cervix has been proposed (e.g. a short cervix is syndromic in nature).…”

Vaginal progesterone in risk reduction of preterm birth in women with short cervix in the midtrimester of pregnancy

“…Ultrasound allows objective evaluation of CL, but TVS is favored over TAS. TAS findings result in greater scatter, higher failure rates (6.7% compared to <1% with TVS),13 and longer cervix estimation from full maternal bladder and resultant higher false-negative rates 14. TVS is an easy skill to learn for sonographers with reported inter- and intraobserver variability of <5% (or 2–4 mm) 11,15.…”

“…Despite the low sensitivity, the high negative predictive value (>97%) across all trials,18 makes CL by TVS a useful screening tool for low-risk pregnant women. A sCL is a good screening predictor as it heralds onset of preterm delivery weeks prior, to allow for intervention to prevent it 14. In addition, sCL can be diagnosed reliably and easily by ultrasound which can be performed at the time of an already scheduled visit for fetal anatomic survey.…”