Transvaginal Ultrasound Cervical Length Research Articles

Transvaginal ultrasound cervical length for prediction of spontaneous labour at term: a systematic review and meta-analysis.

The possibility to predict the delivery date is a question frequently raised by pregnant women. However, a clinician has currently little to predict when a woman at term will deliver. To evaluate the predictive accuracy of transvaginal ultrasound (TVU) cervical length (CL) for spontaneous onset of labour in singleton gestation enrolled at term by a meta-analysis. We performed a literature search in electronic databases. We included only studies assessing the accuracy of TVU CL in prediction of spontaneous onset of labour in singleton gestations with vertex presentation who were enrolled at term. The primary outcome was the accuracy of CL for prediction of spontaneous labour within 7days. Pooled sensitivities and specificities were calculated. Five studies including 735 singleton gestations were included. For the prediction of spontaneous labour within 7days for CL <30mm the pooled sensitivity was 64% and pooled specificity was 60%. The higher the CL, the better the sensitivity; the lower the CL, the better the specificity. A woman with a singleton gestation at term and a TVU CL of 30mm has a <50% chance of delivering within 7days, while one with a TVU CL of 10mm has an over 85% chance of delivery within 7days. TVU CL at term has moderate value in predicting the onset of spontaneous labour. A woman with a TVU CL of 10mm or less has a high chance of delivering within a week. Cervical length at term has moderate value in predicting the onset of spontaneous labour.

Menace d’accouchement prématuré : reproductibilité du test de détection de la PAMG-1 avant, puis après toucher vaginal et cervicométrie

ObjectivesWith current diagnostic resources, it is impossible to predict if a patient consulting in the obstetrics emergencies with symptoms of preterm labor, preterm delivery or not. A novel test for the detection of time to spontaneous preterm delivery was developed and would predict imminent delivery in 7 or 14 days from the time of testing. The diagnostic performances of detection test of PAMG-1 have been validated before digital examination. However digital examination is usually made in first line. The objective of this study was to assess the reproducibility of these diagnostic performances after digital examination and transvaginal ultrasound cervical length. MethodsA prospective and observational study was conducted in a level 3 maternity (University Hospital of Saint-Etienne), from June 2013 to January 2014. Patients consulted in the obstetrics emergencies for threatened preterm birth between 24–34 weeks were enrolled with written and signed consent. Reproducibility of this test was assessed after digital examination, transvaginal ultrasound cervical length and a long time after all investigations. ResultsForty-one patients were included in our study. Average gestational age was 29 weeks, digital examination was changed in 36 patients, whereas cervical length was less than 26mm for only 17 patients. In our study, 100% of tests results remain negative or positive after digital examination and 95,1% after transvaginal ultrasound. Our results confirmed this excellent specificity (97.5% [IC 95%; 86.8–99.9]) and negative predictive value (97.5% [IC 95%; 86.8–99.9]). ConclusionThis work allowed to demonstrate the reproducibility of detection test of PAMG-1 after a digital examination. An initial management with detection test of PAMG-1 could allow reducing the rate of unnecessary hospitalization.

La prévention de l’accouchement prématuré par le pessaire : retour des outils mécaniques en obstétrique ?

To review the available data in the literature on the use of pessaries in preventing preterm birth. We searched PubMed and the Cochrane library with pessary preterm birth. Fifty-eight papers were identified, most of them with little scientific value. A randomized study, including 385 singleton pregnancies with a transvaginal ultrasound cervical length less than 25 mm between 18 and 22 WG, shows a reduction of spontaneous prematurity before 34 WG in the pessary group, with an OR of 0.18 (95%CI: 0.08-0.37). Another study on multiple pregnancies randomized between 12 and 20 WG, with a cervix measured by ultrasound between 16 and 22 WG, showed a reduction of neonatal morbidity in the pessary group (RR: 0.42; 95%CI: 0.19-0.91) in a sub-group with a cervical length<38 mm. These first results from randomized controlled study are encouraging. Other studies on singleton and twin pregnancies are ongoing or about to start.

Second Trimester Cervical Length and Its Association with Vaginal Birth after Cesarean Delivery.

This study aims to evaluate the relationship between cervical length (CL) and trial of labor after cesarean (TOLAC) delivery. This retrospective cohort study evaluated second trimester CL and likelihood of successful TOLAC. Women undergoing TOLAC from January 2009 to December 2011 who underwent transvaginal ultrasound CL between 18(0/7) to 23(6/7) weeks gestation were included. The threshold for CL was assessed using a receiver operating characteristics curve, with ≥ 45 mm determined to be the optimal threshold. Women with CL < 45 mm were compared with women with CL ≥ 45 mm with respect to TOLAC. Multivariate analysis was used to assess the association of CL with TOLAC. A total of 45 patients met inclusion criteria, 14 (31%) with a long CL (≥ 45 mm) and 31 (69%) with CL < 45 mm. Groups did not differ in demographics or factors predictive of vaginal birth after cesarean (VBAC) delivery. More women with CL < 45 mm had successful VBAC (81%) than women with long CL (43%, relative risk 1.9, p = 0.03). Prior vaginal delivery and CL < 45 mm were both significant predictors of VBAC (odds ratio 1.8 and 2.0, respectively). CL < 45 mm is associated with VBAC.

Cost-effectiveness of transvaginal ultrasound cervical length screening in singletons without a prior preterm birth: an update

We sought to reevaluate the cost-effectiveness of universal transvaginal ultrasound (TVU) cervical length (CL) screening in singleton pregnancies without prior spontaneous preterm birth. We developed a decision model to assess costs and effects of universal TVU CL screening at 18-23 weeks' gestation compared to routine care for singleton pregnancies without prior preterm birth. Based on recent data, the model contains the following updates: (1) reduced incidence of CL ≤20 mm at initial screening ultrasound (0.83%), (2) vaginal progesterone supplementation for women with CL ≤20 mm, (3) additional ultrasound(s) for women with CL 21-24.9 mm, and (4) the assumption that vaginal progesterone reduces the rate of preterm birth <34 weeks' gestation by 39% if a short CL is diagnosed. The primary outcome was incremental cost-effectiveness ratio. We assumed a willingness to pay of $100,000 per quality-adjusted life year (QALY) gained. Additional outcomes included incidence of offspring with long-term neurological deficits and neonatal death. Sensitivity analyses were performed to assess the robustness of the results. For every 100,000 women screened, universal TVU CL screening costs $9132 compared to routine care. Screening results in 215 QALYs gained and 10 fewer neonatal deaths or neonates with long-term neurologic deficits per 100,000 women screened. Based on the updated data, universal CL screening in low-risk women remains a cost-effective strategy (incremental cost-effectiveness ratio = $43/QALY), but is not cost saving as previously estimated. Sensitivity analyses reveal that when incidence of TVU CL ≤20 mm is <0.31%, universal TVU CL screening is no longer cost-effective. Additionally, when TVU CL costs >$314, progesterone reduces preterm delivery risk before 34 weeks <19%, or the incidence of a TVU CL 21-24.9 mm is >6.5%, CL screening is also no longer cost-effective. Despite the reduced incidence and efficacy used in this model, universal TVU CL continues to be cost-effective when compared to routine care in singletons without prior preterm birth.

Prior ultrasound-indicated cerclage: how should we manage the next pregnancy?

ObjectiveTo determine the subsequent need for cerclage and pregnancy outcome, in women with a prior ultrasound-indicated cerclage. Study DesignAnalysis of a prospectively collected database from November 2010 to July 2014 from 15 Preterm Surveillance clinics across the UK was performed. Women with an index and previous singleton pregnancy with an ultrasound-indicated cerclage were eligible for inclusion (n=55). Previous ultrasound-indicated cerclage was defined as cerclage inserted prior to 24 weeks’ for cervical length <25mm as detected by transvaginal ultrasound. Women were managed in their subsequent pregnancy with either history-indicated cerclage, transvaginal ultrasound surveillance of cervical length with cerclage if <25mm or transabdominal cerclage at the discretion of the physician. Exact logistic regression was used to estimate the odds ratio on the chance of delivery before 34 weeks’. Adjustments were made for major risk factors for prematurity: previous spontaneous preterm birth, previous late miscarriage (16+0 to 23+6 weeks’) and previous cervical surgery; both individually and in combination. ResultsOf the 55 eligible women, 23 underwent history-indicated cerclage, 23 underwent transvaginal ultrasound cervical length surveillance and 8 underwent abdominal cerclage in the index pregnancy. Of those that had ultrasound surveillance, 13 (57%) did not require cerclage and all delivered after 34 weeks’. Of those that had a history-indicated cerclage, six delivered before 34 weeks’. Therefore, women that received a history-indicated cerclage had greater risk of preterm birth compared to women that underwent ultrasound surveillance with cerclage insertion only if cervical shortening was detected (OR 0.09 95% CI 0.00–0.74, p=0.02). Adjustments for risk factors for preterm birth did not significantly affect this risk. ConclusionIn women with prior ultrasound-indicated cerclage, who undergo cervical surveillance in the next pregnancy, the majority will not require intervention for a short cervix. Those women receiving a history-indicated vaginal cerclage were more likely to deliver preterm; this cannot be explained by their risk status. All women receiving an abdominal elective cerclage had good outcomes. Ultrasound surveillance is appropriate in women with a prior ultrasound-indicated cerclage who do not require an abdominal cerclage.

148: Cost-effectiveness of transvaginal ultrasound cervical length screening in singletons without prior preterm birth: an update

148: Cost-effectiveness of transvaginal ultrasound cervical length screening in singletons without prior preterm birth: an update

Pros and cons of maternal cervical length screening to identify women at risk of spontaneous preterm delivery.

Large randomized controlled trials have demonstrated that universal maternal cervical length screening and treatment with daily vaginal progesterone in women with short cervical length reduces the risk of preterm birth, but large numbers of women must be screened to prevent a relatively small number of preterm deliveries. Issues that should be considered while implementing universal cervical length screening include: (1) the standards of quality and reproducibility for transvaginal ultrasound cervical length ascertainment; and (2) the implications of screening on the application of therapeutic strategies to populations not known to benefit (so-called "indication creep"). Optimal strategies to employ cervical ultrasound and progesterone treatment might be revealed by additional studies investigating cervical length cutoffs, frequency of screening, selective screening in higher-risk groups, and the use of transabdominal cervical length screening as a surrogate for transvaginal cervical length screening.

Is universal cervical length screening indicated in women with prior term birth?

To determine whether universal transvaginal ultrasound (TVU) cervical length (CL) screening is indicated in women with prior term births. We conducted a prospective cohort study from Jan. 1, 2012, to June 30, 2013, of singleton gestations between 18 0/7-23 6/7 weeks undergoing TVU CL screening for prediction of spontaneous preterm birth (sPTB). Women with a prior sPTB, with cerclage, and without delivery data available were excluded. Primary outcomes were the incidence of a CL ≤20 mm, and rates of sPTB <37, <34, and <32 weeks gestation among women with prior term births vs nulliparous women. A total of 1569 women underwent TVU CL screening; 18 women with a prior iatrogenic preterm birth were excluded. Of those screened, 756 (48.7%) had a prior term delivery and 795 (51.3%) were nulliparous. Women with prior term births differed from nulliparous women with respect to age, body mass index, race, smoking status, and prior dilation and curettage. After adjustment for these confounders, there was no statistical difference in the incidence of CL ≤20 mm (0.8 vs 1.4%; adjusted odds ratio, 0.35; 95% confidence interval, 0.12-1.03) among women with prior term births compared with nulliparous women. Rates of sPTB <37, <34, <32 weeks were similar in women with a prior term birth compared with nulliparous women. The overall incidence of sPTB <37 weeks was 3.2% in women with a prior term birth and 5.0% in nulliparous women. When a CL ≤20 mm was identified, 3 of 6 women with prior term birth delivered at <37 weeks compared with 8 of 11 nulliparous women. There were no identified differences between the odds of sPTB between women with a CL ≤20 mm who had a prior term birth compared with nulliparous women. Women with prior term birth have a trend toward a lower incidence of CL ≤20 mm, compared with nulliparous women. Further studies are needed to determine whether women with prior term births should be included or excluded from TVU CL screening.

There is still insufficient data to recommend screening twin pregnancies with transvaginal ultrasound cervical length, but this might change soon!

There is still insufficient data to recommend screening twin pregnancies with transvaginal ultrasound cervical length, but this might change soon!

Evaluation of pregnant women at risk of preterm delivery by correlating ultrasound markers with Insulin-like growth factor binding protein-1

The aim of the study was to assess the preterm birth risk, by correlating Actim Partus test with ultrasound markers. The present study was conducted in the Clinic of Obstetrics and Gynecology from Municipal Hospital, Craiova from Romania, on 67 pregnant women from whom we selected 34 at risk of preterm delivery with gestational ages between 22 and 32 weeks. To include pregnant women in the premature birth risk group we observed personal obstetrical history, transvaginal ultrasound cervical length (CL) (≤ 25 mm, ± funneling), Actim Partus test and the correlations between these elements. For inclusion in the group we need to determinate CL and test every two weeks. Our results showed that the women who had a concentration of pheripheral insulin-like growth factor binding protein-1 less than 10 ug/l (negative) did not deliver prematurely or in the next two weeks following the testing. None of the women tested gave birth before 35 weeks of pregnancy. Treatment was effective in these cases. Evidence suggests that a CL < 25-25 mm increases moderately preterm birth rate at < 37 weeks, although values between 20 and 25 mm do not exclude preterm birth, as well as associating funneling. Actim Partus test is a quick, facile and reliable test, which requires no additional equipment, and could be further used to monitor the rate of premature births in pregnant women. <br/><a href=

Prior Ultrasound-Indicated Cerclage

INTRODUCTION: To evaluate pregnancy outcomes of women with a history of ultrasound-indicated cerclage for a short cervix who in subsequent pregnancy either were followed by transvaginal ultrasound cervical length screening or received a history-indicated cerclage. METHODS: Retrospective cohort study was performed from 1993 to 2012 involving women with an index singleton pregnancy and history of ultrasound-indicated cerclage. Prior ultrasound-indicated cerclage was defined as cerclage placed for cervical length less than 25 mm before 24 weeks of gestation in women at high risk for preterm birth. At our institution, women with a history of ultrasound-indicated cerclage were managed in their subsequent pregnancy either by transvaginal ultrasound cervical length screening or by history-indicated cerclage, at the physician's discretion (Fig. 1). In the transvaginal ultrasound cervical length group, if cervical length became less than 25 mm before 24 weeks of gestation, an ultrasound-indicated cerclage was performed. In the history-indicated cerclage group, history-indicated cerclage was placed at approximately 12–15 weeks of gestation. Primary outcome was spontaneous preterm birth at less than 35 weeks (Table 1).RESULTS: Twenty-eight women met the inclusion criteria. Of these 28 women, 13 were in the transvaginal ultrasound cervical length group and 15 in the history-indicated cerclage group. Demographics were similar in both the groups, except earliest gestational age of prior spontaneous preterm birth (Table 1). The odds of spontaneous preterm birth at less than 35 weeks of gestation for the two groups was similar (odds ratio 0.54, 95% confidence interval 0.04–6.77). Secondary outcomes were also similar in two groups except birth weight (Table 1). CONCLUSION: Women with prior ultrasound-indicated cerclage have similar outcomes if they are managed in the next pregnancy by either transvaginal ultrasound cervical length screening and ultrasound-indicated cerclage placement if cervical length is less than 25 mm before 24 weeks of gestation or by history-indicated cerclage. Our study results are limited by small sample size. There are currently no other studies evaluating this clinical dilemma.

Use of a Cervicometer in Assessing Cervical Length and Risk of Preterm Birth

INTRODUCTION: Although current obstetric practice guidelines suggest cervical length assessment in singletons for preterm birth risk, transvaginal ultrasonography has availability limitations. CerviLenz is a disposable device to measure vaginal cervical length. We sought to determine the threshold CerviLenz measurement with optimal specificity and sensitivity for diagnosis of short cervix by transvaginal ultrasonography and compare the abilities of CerviLenz and transvaginal ultrasonography to predict preterm birth. METHODS: Women with singleton pregnancies and no cervical anomalies or surgery or premature labor were consented, enrolled, and followed to delivery. Transvaginal ultrasonography and CerviLenz cervical length measurements were obtained by independent examiners at 17–23 weeks of gestation. A central reader certified sonographers and reviewed all transvaginal ultrasound scans. RESULTS: Based on 358 patients, receiver operator curves indicated optimal CerviLenz threshold of 30 mm to detect short cervix (transvaginal ultrasound cervical length at or below 25 mm). CerviLenz detected a short cervix with a negative predictive value (NPV) of 100%, sensitivity of 100%, and specificity of 46% (Table 1). Preterm birth before 37 weeks of gestation occurred in 25 (7%) patients. Area under the curve analyses for preterm birth before 28, 32, or 35 weeks of gestation revealed similar results for CerviLenz and transvaginal ultrasonography. For preterm birth before 37 weeks of gestation, CerviLenz had greater sensitivity (60%, transvaginal ultrasonography 16%) and transvaginal ultrasonography had higher specificity (97%, CerviLenz 44%).CONCLUSIONS: At a 30-mm threshold, CerviLenz has high NPV, high sensitivity, and moderate specificity to detect a short cervical length in the second trimester. CerviLenz is similar to transvaginal ultrasonography in prediction of preterm birth at 28–37 weeks of gestation. Based on high NPV, CerviLenz is clinically useful in identifying women not at risk for preterm birth, having potential to substantially reduce the need for transvaginal ultrasound screening in singletons.

Does Second-Trimester Cervical Length Predict Prolonged Pregnancy?

INTRODUCTION: Third-trimester cervical length has been correlated with delivery timing. Given that second-trimester ultrasonography is routine practice, we sought to evaluate whether second-trimester cervical length is associated with prolonged pregnancy. METHODS: We performed a secondary analysis of data involving women with singleton gestations between 18 0/7 and 23 6/7 weeks of gestation undergoing universal transvaginal ultrasound cervical length screening for preterm birth prediction from January 1, 2012, to December 30, 2012. Women with prior spontaneous preterm births, cerclage in situ, and deliveries at outside institutions were excluded. Women were included if they had spontaneous labor, rupture of membranes, or reached 41 weeks of gestation. The primary outcome was the incidence of prolonged pregnancy (41 0/7 weeks of gestation and beyond). A receiver operating characteristic curve was calculated to identify the threshold cervical length predictive of a prolonged pregnancy. Statistical analysis was performed using SPSS 20.0. RESULTS: Of the 660 women who met inclusion criteria, 108 (16.4%) had prolonged pregnancies. Women with prolonged pregnancies had a higher mean body mass index and were less likely to have had a prior vaginal delivery compared with women without prolonged pregnancies. Women with prolonged pregnancies also had higher mean cervical length (43 compared with 42 mm, P=.057) and a higher incidence of cervical length greater than 30 mm (100% compared with 96%, P=.035; Table 1). The receiver operating characteristic curve demonstrated an area under the curve of 0.542 (standard error 0.027; Figure 1); no optimal cervical length was predictive of a prolonged pregnancy.CONCLUSIONS: Second-trimester cervical length is not predictive of prolonged pregnancy.

Evaluation of the ability of cervical length and fetal fibronectin measurement to predict preterm delivery in asymptomatic women with risk factors

Objective: To evaluate the power of transvaginal ultrasound cervical length (CL) and fetal fibronectin (fFN) measurement for the prediction of preterm delivery (PTD) in asymptomatic women with risk factors.Methods: Between January 2010 and October 2012, 218 women with singleton pregnancies and a high risk for PTD (i.e. prior history of PTD, cervical surgeries, late miscarriages, uterine abnormalities or premature rupture of the membranes) were selected. CL was measured by transvaginal ultrasonography between 14 and 22 weeks, and a CL < 2.5 cm was considered to be short. The fFN was measured with a sterile speculum examination. The primary outcome was the spontaneous PTD rate at <34+0 and <37+0 weeks, and the PTD rate was analyzed by either of two methods alone or combined.Results: There were 213 cases included in the analysis, and 47 women (22.1%) had positive fFN. The average CL of women with positive fFN (2.3 ± 0.9 cm) was significantly shorter than that of women with negative fFN (3.1 ± 0.8 cm; p = 0.02). There were 25 (11.7%) and 38 (18.8%) cases with PTD at <34+0 and <37+0 weeks, respectively. By individual analyses, the highest PTD rate was 51.2% in women with positive fFN at <37+0 weeks. The sensitivity and diagnostic efficiency values for PTD prediction by CL were low at <34+0 and <37+0 weeks. The values of diagnostic efficiency by fFN were >80% at <34+0 and <37+0 weeks. In the combined analysis, the highest PTD rate was 57.1% in women with CL ≤ 2.5 cm and positive fFN at <37+0 weeks. The Kaplan–Meier curve indicated that there were significant differences among the four groups (χ2 = 54.261; p = 0.000).Conclusions: These results indicate a significant correlation between fFN and PTD prediction. The PTD prediction could be enhanced by combined CL and fFN measurement.

Transperineal versus transvaginal ultrasound cervical length measurement and preterm labor.

The aim was to evaluate the agreement between and the reproducibility of transperineal and transvaginal ultrasound cervical length measurements performed by the duty obstetrical team in case of preterm labor. The acceptability of transperineal ultrasonography was also assessed. Pregnant patients between 25 and 34weeks of gestation with contractions and a clinically modified cervix were included. Order of ultrasonography examination (transperineal or transvaginal first) and rank of operator (resident or senior) were allocated randomly. Agreement was assessed using the intraclass correlation coefficient (ICC) and the Bland and Altman plot. The patient's discomfort and preference for either method were assessed with a questionnaire. 62 patients admitted for preterm labor between 25 and 34weeks of gestation were included. Six seniors and nine residents took part in the study. Among the 51 patients with an interpretable transperineal ultrasound scan, median cervical length measurements with the transperineal and the transvaginal technique were, respectively, 25mm (0-53) and 27mm (4-51). Concordance was good with an ICC of 0.83 [IC 95%=(0.73-0.90)]. Transperineal ultrasonography was preferred in 56.5% of cases. In case of preterm labor, cervical length measurement with transperineal ultrasonography seems reproducible and can be performed by the obstetric team on duty.

Comparison of the POP-Q examination, transvaginal ultrasound, and direct anatomic measurement of cervical length

Our objective was to determine the relationship between the Pelvic Organ Prolapse Quantification (POP-Q) examination for determining cervical length (CL) and CL at hysterectomy. Secondary objectives were to define cervical elongation using both measures in a urogynecologic population, determine the relationship between POP-Q estimate and CL on ultrasound (US) and examine the interobserver reliability of each mode of measurement. This was a prospective cohort study of women scheduled for hysterectomy at the Los Angeles County + University of Southern California (LAC + USC) medical center. CLs were measured by POP-Q and at the time of hysterectomy. Transvaginal US CLs were determined when available. Exam CL (eCL) was compared with anatomic (aCL) and US (uCL) CL. Repeat measures of eCL, uCL, and aCL were all compared for interobserver reliability. The study enrolled 151 women. Median eCL was 3.0 cm (0.5-9.0) (n = 149); average uCL was 2.3 cm ± 0.7 (n = 108), average aCL 2.8 cm ± 1.1 (n = 87); eCL correlated fairly with aCL (r = 0.3, p = 0.005, n = 88) but poorly with uCL (r = -0.13, p = 0.18, n = 105); uCL correlated poorly with aCL (r = 0.19, p = 0.14, n = 64). Interobserver reliability for eCL and aCL were good to excellent (eCL α=0.881; aCL α=0.889) but for uCL adequate (α=0.699). The 97.5 percentile cutoff for aCL was 5.0 cm and for eCL 8.0 cm. The POP-Q examination estimate of CL correlates fairly with aCL at the time of hysterectomy; uCL does not appear to correlate with aCL or eCL. Cervical elongation may be defined as an anatomic length of 5.0 cm or a POP-Q estimate of 8.0 cm.

Can transabdominal ultrasound identify women at high risk for short cervical length?

To determine whether transabdominal cervical length screening could identify women at high risk for having a short cervix on transvaginal ultrasound. Retrospective cohort study. Tertiary referral center. A total of 703 patients with a singleton pregnancy at 18 to 23(+6) weeks of gestation who underwent transabdominal and transvaginal cervical length assessment during anatomy ultrasound at a single institution between January 2007 and October 2011. Electronic medical records were reviewed to identify women who met the study criteria. The primary outcome was the number of women with a short transabdominal cervical length (defined as ≤ 30 mm) who needed to undergo transvaginal ultrasound to detect one woman with a short transvaginal cervical length of ≤ 20 mm. In all, 703 patients were included in the primary analysis; 3.42 women with transabdominal cervical length ≤ 30 mm needed to undergo transvaginal ultrasound to detect one woman with transvaginal ultrasound cervical length ≤ 20 mm. Of women with short transvaginal cervical length ≤ 20 mm, 89.8% had a transabdominal measurement ≤ 30 mm and 96.7% had a transabdominal measurement ≤ 33 mm. Screening of transabdominal cervical length may represent a useful strategy for detecting women with short cervix on transvaginal ultrasound.

PF.02 The Role of Quantitative Fetal Fibronectin and Cervical Length in Predicting Spontaneous Preterm Birth in Multiple Pregnancies

BackgroundMultiple pregnancies are associated with a higher risk of spontaneous preterm birth (sPTB). Whilst fetal fibronectin (fFN) and cervical length (CL) measurement can predict sPTB in singleton pregnancies (Kurtzman et...

Cervical assessment by ultrasound for preventing preterm delivery.

Measurement of cervical length (CL) by transvaginal ultrasound (TVU) is predictive of preterm birth (PTB). It is unclear if this screening test is effective for prevention of PTB. To assess the effectiveness of antenatal management based on transvaginal ultrasound of cervical length (TVU CL) screening for preventing PTB. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 August 2012), reviewed the reference lists of all articles and contacted experts in the field for additional and ongoing trials. Published and unpublished randomized controlled trials including pregnant women between the gestational ages of 14 to 32 weeks screened with TVU CL for risk of PTB. This review focuses exclusively on studies based on knowledge versus no knowledge of TVU CL results. All potential studies identified from the search were independently assessed for inclusion by three review authors. We also analyzed studies for quality measures and extracted data. Of the 13 trials identified, five were eligible for inclusion (n = 507). Three included singleton gestations with preterm labor (PTL); one included singleton gestations with preterm premature rupture of membranes (PPROM); and one included twin gestations with or without PTL.In the three trials of singleton gestations with PTL, 290 women were randomized; 147 to knowledge and 143 to no knowledge of TVU CL. Knowledge of TVU CL results was associated with a non-significant decrease in PTB at less than 37 weeks (22.3% versus 34.7%, respectively; average risk ratio 0.59, 95% confidence interval (CI) 0.26 to 1.32; two trials, 242 women) and at less than 34 weeks (6.9% verus 12.6%; RR 0.55, 95% CI 0.25 to 1.20; three trials, 256 women). Delivery occurred at a later gestational age in the knowledge versus no knowledge groups (mean difference (MD) 0.64 weeks, 95% CI 0.03 to 1.25; three trials, 290 women). For all other outcomes for which there were available data (PTB at less than 34 or 28 weeks; birthweight less than 2500 grams; perinatal death; maternal hospitalization; tocolysis; and steroids for fetal lung maturity), there was no evidence of a difference between groups.The trial of singleton gestations with PPROM (n = 92) evaluated as its primary outcome safety of TVU CL in this population, and not its effect on management. There was no evidence of a difference in incidence of maternal and neonatal infections between the TVU CL and no TVU CL groups.In the trial of twin gestations with or without PTL (n = 125), there was no evidence of a difference in PTB at less than 36, 34, or 30 weeks, gestational age at delivery, and other perinatal and maternal outcomes between the TVU CL and the no TVU CL groups. Life-table analysis revealed significantly less PTB at less than 35 weeks in the TVU CL group compared with the no TVU CL group (P = 0.02). Currently, there is insufficient evidence to recommend routine screening of asymptomatic or symptomatic pregnant women with TVU CL. Since there is a non-significant association between knowledge of TVU CL results and a lower incidence of PTB at less than 37 weeks in symptomatic women, we encourage further research. Future studies should look at specific populations separately (e.g., singleton versus twins; symptoms of PTL or no such symptoms), report on all pertinent maternal and perinatal outcomes, and include cost-effectiveness analyses. Most importantly, future studies should include a clear protocol for management of women based on TVU CL results, so that it can be easily evaluated and replicated.