Correlation Between Cervical Lengths Measured by Transabdominal and Transvaginal Sonography for Predicting Preterm Birth

Comparison between trans-vaginal and trans-abdominal ultrasound examination of the cervix in the second trimester of pregnancy: a prospective study

OBJECTIVES

To compare transvaginal (TV) and trans-abdominal (TA) ultrasound assessment of cervical length (CL) at the time of the second-trimester scan for fetal anomalies.

METHODS

This was a prospective study including consecutive pregnant women attending the low-risk ultrasound clinic of two fetal medicine centres in Italy. The inclusion criteria were women between 19 + 0 and 22 + 0 weeks of gestation, attending the prenatal ultrasound clinic for the routine second trimester screening for fetal anomalies. The primary outcome was to compare the CL measurement obtained at TV compared to TA ultrasound; the secondary outcome was to report the inter and intra-observer variability of CL measured with the two different approaches. All women underwent TV and TA assessment of the cervix performed by two experienced certified operators, blinded to each other. Intra-class correlation coefficients (ICC) and Bland-Altman analyses were used to analyse the data.

RESULTS

Two hundred and fifty women were included in the analysis. All women had anteverted uterus. The mean gestational age at ultrasound was 20.7 ± 0.7 weeks; 1.2 % (3/250) scans were performed at 19 weeks, 49.2 % (123/250) at 20 weeks, 44.8 % (112/250) at 21 weeks and 4.8 % (12/250) at 22 weeks of gestations. Identification of the major landmarks of CL at TA ultrasound was achieved in all the included cases. There was good reliability between CL measured at TA (ICC 0.95, 95 % CI 0.93-0.97 for observer 1 and 0.92 %, 95 % CI 0.89-0.94 for observer 2) and TV ultrasound 0.97, 95 % CI 0.96-0.98 for observer 1 and 0.96, 95 % CI 0.95-0.97 for observer 2). There was also good reliability between the two observers for both the TA and TV assessment of the CL. Mean TA CL was 41.4 ± 5.5 for observer 1 and 40.5 ± 4.8 for observer 2 with no significant differences between the two measurements (mean difference 0.92 mm, 95 % CI -9.7 to 11.2). Likewise, there was no difference between the CL measured at TV ultrasound between the two observers (mean difference -0.83 mm, 95 % CI -5.97 to 4.30). Finally, there was no difference in the mean CL measured at TA compared to TV, either considering the overall population of women (mean difference: -0.43, 955 CI -8.65 to 7.79), or when stratifying the analysis according to the parity status and the operator.

CONCLUSIONS

Among experienced operators, there was no difference between TV and TA ultrasound assessment of the CL at the time of the routine anomaly scan for fetal anomaly.

Comparison of Transabdominal and Transvaginal Sonograms in Evaluation of Cervical Length During Pregnancy

Objective:

A short cervix during pregnancy indicates a higher risk of preterm delivery. Transvaginal sonography is widely used for the detection of a short cervix. The literature indicates that 21–24 weeks is the most sensitive gestational age to assess transvaginal cervical length (TV CL) of ≤2.5 cm for potential preterm delivery. Pregnancies between 18 and 20 weeks’ gestation are generally performed transabdominally; thus, it could be beneficial to have a recognized correlation between the transabdominal cervical length (TA CL) measurement and the TV CL measurement at this earlier time period.

Materials and Methods:

An online database search produced 13 research articles to be reviewed. Inclusion criteria consisted of TA CL and TV CL assessment of singleton pregnancies with intact membranes.

Results:

Findings indicate high diagnostic yield when a TA CL of <2.9 cm or TV CL of <2.5 cm is used for defining a shortened cervix when measured between 18 and 20 weeks’ gestation.

Conclusion:

This review of the literature indicates a correlation between average TA CL and average TV CL measurements, although the relationship widens as CLs become shorter.

Guideline No. 401: Sonographic Cervical Length in Singleton Pregnancies: Techniques and Clinical Applications

OBJECTIVES

• To assess the association between sonography-derived cervical length measurement and preterm birth. • To describe the various techniques to measure cervical length using sonography. • To review the natural history of the short cervix. • To review the clinical uses, predictive ability, and utility of sonography-measured short cervix.

OUTCOMES

Reduction in rates of prematurity and/or better identification of those at risk, as well as possible prevention of unnecessary interventions.

INTENDED USERS

Clinicians involved in the obstetrical management or cervical imaging of patients at increased risk of a short cervix.

TARGET POPULATION

Women at increased risk of a short cervix or at risk of preterm birth.

EVIDENCE

Literature published up to June 2019 was retrieved through searches of PubMed and the Cochrane Library using appropriate controlled vocabulary and key words (preterm labour, ultrasound, cervix, cervical insufficiency, transvaginal, transperineal, cervical length, fibronectin). Results were restricted to general and systematic reviews, randomized controlled trials, controlled clinical trials, and observational studies. There were no date or language restrictions. Grey (unpublished) literature was identified through searching the websites of health technology assessment agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The evidence and this guideline were reviewed by the Diagnostic Imaging Committee of the Society of Obstetricians and Gynaecologists of Canada, and the recommendations were made and graded according to the rankings of the Canadian Task Force on Preventive Health Care (Online Appendix Table A1).

BENEFITS, HARMS, COSTS

Preterm birth is a leading cause of perinatal morbidity and mortality. Use of the sonographic technique reviewed in this guideline may help identify women at risk of preterm birth and, in some circumstances, lead to interventions that may reduce the rate of preterm birth. SUMMARY STATEMENTS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES): RECOMMENDATIONS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES).

The State of the Science of Preterm Birth: Assessing Contemporary Screening and Preventive Strategies

Preterm birth remains a leading cause of morbidity and mortality during the perinatal and neonatal periods. Now affecting approximately 1 in 10 births in the United States, preterm birth often occurs spontaneously and without a clear etiology. Careful assessment of risk factors, however, identifies vulnerable women allowing targeted interventions such as progestogen therapy and cerclage. This article is intended to highlight preterm birth risk factors and current predictive and preventive strategies for midwives, nurse practitioners, clinical nurse specialists, and perinatal nurses.

Diagnostic accuracy of cervical elastography in predicting preterm delivery: A systematic review and meta-analysis

BACKGROUND

The aim of the study was to evaluate the diagnostic accuracy of cervical elastography in predicting preterm delivery (PTD).

METHODS

We searched the PubMed, EMBASE, and Cochrane databases to identify relevant studies that applied ultrasound (US) elastography to assess cervical stiffness and predict PTD. All the studies were published before December 11, 2018, and only studies published in English were collected. The cervical length (CL) was considered a comparator, and the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool was applied to assess the quality of the included studies. Summary receiver operating characteristic (SROC) modeling was performed to evaluate the diagnostic performance of cervical elastography in predicting PTD. Subgroup analyses were also performed.

RESULTS

Seven studies, including 1488 pregnant women, were included in this meta-analysis. Cervical elastography showed a summary sensitivity of 0.84 [95% confidence interval (CI): 0.68, 0.93], a specificity of 0.82 (95% CI: 0.63, 0.93), a diagnostic odds ratio of 25 (95% CI: 7, 93), and an area under the curve (AUC) of SROC of 0.90 (95% CI: 0.87-0.93). CL measurement showed that the AUC of SROC was 0.60 (95% CI: 0.56-0.64). The results of subgroup analysis showed that the summary sensitivity and specificity were different in the QUADAS-2 score subgroups.

CONCLUSION

Cervical elastography is a promising and reliable method to predict PTD. Cervical elastography showed better diagnostic performance to predict PTD than CL measurement.

Screening for spontaneous preterm birth and resultant therapies to reduce neonatal morbidity and mortality: A review

Despite considerable effort aimed at decreasing the incidence of spontaneous preterm birth, it remains the leading cause of perinatal morbidity and mortality. Screening strategies are imperfect. Approaches used to identify women considered by historical factors to be low risk for preterm delivery (generally considered to be women with singleton pregnancies without a history of a previous preterm birth) as well as those at high risk for preterm birth (those with a previous preterm birth, short cervix, or multiple gestation) continue to evolve. Herein, we review the current evidence and approaches to screening women for preterm birth, and examine future directions for clinical practice. Further research is necessary to better identify at-risk women and provide evidence-based management.

Diagnosis and treatment of submucous myoma of the uterus with interventional ultrasound

The value of interventional ultrasound in the diagnosis and treatment of submucous myoma of the uterus was assessed to study the ultrasonographic features of modified sonohysterography for submucous polyp of uterus. A total of 25 patients diagnosed preliminarily as submucous myoma of the uterus via conventional ultrasound examination from June 2014 to December 2016 were enrolled in the study. The diagnosis was made via the comprehensive analysis of ultrasound-guided modified SHG, followed by ultrasound-guided needle biopsy and sclerotherapy of tumor. After modified SHG and ultrasound-guided needle biopsy, 96% (24/25) cases were confirmed pathologically as submucous myoma of the uterus. After treatment, the maximum diameter of myoma in patients with submucous myoma of uterus was significantly different, and the volume of myoma was significantly reduced. After treatment, the clinical symptoms of patients with submucous myoma of the uterus were obviously improved compared to before treatment (P<0.05). It was found in the follow-up after treatment that a small number of patients suffered from mild abdominal pain, increased secretion, slight vaginal bleeding, cold sweat, pale complexion, dizziness and other symptoms, which, however, disappeared after treatment for about 1 week. The score of 36 item Short-Form Health Survey Questionnaire of patients with submucous myoma of the uterus was significantly different before and after treatment (P<0.05). Interventional ultrasonography can effectively diagnose the submucous myoma of uterus. The treatment of submucous myoma of uterus with ultrasound-guided intratumor injection of lauromacrogol is characterized by simple operation, which can effectively reduce the tumor diameter and volume, improve the blood flow in patients, reduce the postoperative adverse reactions and alleviate the patient's pain, so it is a new type of minimally invasive treatment method of submucous myoma of the uterus, and it is worthy of clinical promotion and application.

Comparison of transabdominal and transvaginal ultrasonography for the assessment of cervical length at 16-23 weeks of gestation

The aim of this study was to assess the relationship between transabdominal and transvaginal ultrasonography for the cervical length assessment and to evaluate the predictive value of the transabdominal ultrasonography cervical length assessment for predicting preterm birth. A prospective cohort study was conducted. Transabdominal and transvaginal ultrasonography cervical length assessments were performed in 160 pregnant women between 16 and 23 ^+ 6 weeks of gestation. Transabdominal ultrasonography cervical length assessment was positively correlated with the transvaginal ultrasonography cervical length assessment. Mean ± standard deviation of the cervical length was significantly different between transabdominal and transvaginal ultrasonography (36.4 ± 5.4 vs. 41.2 ± 5.4 mm, p < .001). Transabdominal cervical length was shorter than the transvaginal cervical length with a mean difference of 4.8 mm. The sensitivity, specificity, positive predictive value and negative predictive value for predicting preterm birth when the transabdominal cervical length was ≤35 mm, were 50%, 52.1%, 9.1%, and 91.6%, respectively. In conclusion, transabdominal ultrasonography cervical length assessment is positively correlated with the transvaginal ultrasonography cervical length assessment. Transabdominal cervical length assessment was not a good predictor of preterm birth.