Uterocervical angle versus cervical length in the prediction of spontaneous preterm birth in singleton pregnancy

Uterocervical angle and cervical length measurements for spontaneous preterm birth prediction in low-risk singleton pregnant women: a prospective cohort study

PURPOSE

Preterm birth is the leading cause of early neonatal morbidity and mortality. Strategies to predict preterm birth risk can help improve pregnancy outcomes. Even pregnant women without known risk factors for preterm birth can also experience it. This study aimed to evaluate the ability of the uterocervical angle and cervical length to predict spontaneous preterm birth in low-risk singleton pregnant women.

METHODS

A prospective study on 1107 singleton pregnant women between 16+0 and 23+6 weeks gestation at low risk for spontaneous preterm birth who were treated at the Haiphong Hospital of Obstetrics and Gynecology, Vietnam, between September 2020 and September 2021 was conducted. A single sonographer assessed the cervical length and the uterocervical angle using transvaginal ultrasonography. The patients were followed up until delivery to determine the main pregnancy outcome (spontaneous preterm birth before 37 weeks gestation). The cut-off points for the uterocervical angle and cervical length were established by analyzing the receiver operating characteristic curve. The sensitivity, specificity, likelihood ratio, positive and negative predictive values, and accuracy of the uterocervical angle and cervical length for predicting spontaneous preterm birth were determined.

RESULTS

A uterocervical angle ≥ 99° predicted spontaneous preterm birth at < 37 weeks, with a sensitivity and specificity of 91% and 76%, respectively. A cervical length ≤ 33.8 mm predicted preterm birth at < 37 weeks with a sensitivity and specificity of 25% and 66%, respectively. A uterocervical angle ≥ 99° combined with a cervical length ≤ 33.8 mm yielded the sensitivity, specificity, positive predictive value, likelihood ratio, and accuracy of spontaneous preterm birth prediction of 66%, 93%, 36%, 9, and 91%, respectively; thus provided a significant increase of specificity with an acceptable reduction of sensitivity as compared to cervical length alone.

CONCLUSION

Besides the cervical length, the uterocervical angle can be considered a valuable ultrasound parameter for predicting spontaneous preterm birth in low-risk singleton pregnant women. Combining the uterocervical angle and cervical length yielded stronger spontaneous preterm birth prediction values.

Predictive values of cervix length measurement based on transvaginal ultrasonography

BACKGROUND

Pregnancy is an important process in women's life, which is widely concerned by women. In recent years, the incidence of premature delivery (PTD) becomes more and more higher due to the development of auxiliary reproduction and ovulation induction technologies and the changes of pregnant women's lifestyle and physical quality. PTD not only affects postpartum recovery and causes great physical pains, but it also has adverse effects on the birth state of neonates and even leads to neonatal death.

OBJECTIVE

The predictive values of cervix length (CL) measurement based on transvaginal ultrasonography (TVUS) and pathological examination of placenta for premature delivery (PTD) were investigated and the correlation between PTD and infection was analyzed.

METHODS

120 pregnant women with PTD or high-risk factors for PTD admitted to The Affiliated Hospital of Southwest Medical University between February 2020 and March 2022 were included as the subjects and underwent pathological examination of placenta and TVUS for CL measurement. The final gestational age was set as the standard for the evaluation on the predictive values of pathological examination of placenta and TVUS. What's more, 36 subjects in PTD group and 84 in normal delivery group (control group) underwent pathological examination of placenta for the analysis of the correlation between PTD and infection.

RESULTS

The joint inspection method showed significantly better sensitivity, specificity, PPV, and NPV compared to single CL or pathological examination of the placenta (P< 0.05). Among pregnant women, those with CL ⩽ 30 mm and positive placental pathology had a higher proportion compared to those with CL > 30 mm and negative placental pathology (P< 0.05). Furthermore, the incidence of Ureaplasma Urealyticum (UU), Chlamydia Trachomatis (CT), and Chorioamnionitis (CA) in vaginal discharge of the preterm delivery (PTD) group was significantly higher than that of the control group (P< 0.05).

CONCLUSION

The combination of CL ⩽ 30 mm and positive placental pathology could effectively predict PTD and placental infection was notably correlated with the occurrence of PTD.

Prediction of Preterm Birth with the Uterocervical Angle in Singleton Pregnancies Treated with a Cervical Pessary

BACKGROUND

Cervical pessaries are an established therapy option for patients at risk for spontaneous preterm birth (sPTB). The uterocervical angle (UCA) remains a promising sPTB predictor. However, its clinical significance has yet to be described in patients treated with a pessary.

METHODS

This study analyzed data of patients treated with a pessary because of cervical shortening in singleton pregnancies. The patients were divided into 2 groups according to transvaginal ultrasound findings: the funneling group (n = 68) and the no-funneling group (n = 42). Moreover, we analyzed patients within these prespecified groups according to the UCA < 95° and ≥ 95°.

RESULTS

Delivery occurred significantly earlier in patients treated with a pessary and with a high UCA ≥ 95°(p = 0.006). The median gestational age at delivery in patients treated with a pessary and with no funneling and a UCA < 95° vs. ≥ 95° were 39.00 and 36.14 weeks, respectively (p = 0.005). In cases with funneling and a UCA < 95° vs. ≥ 95° the mean gestational age at delivery was 38.14 and 38.07 weeks respectively (p=1,00). There was a significant negative linear correlation between UCA and the gestational age at delivery in all patients (p = 0.04), which was even profound in the group without funneling (p = 0.0002). However, we found no significant correlation between cervical length and gestational age at delivery in all patients (p = 0.42) as well as in the group without funneling (p = 0.28).

CONCLUSION

In spite of pessary treatment, patients with UCA ≥ 95° presented with a higher risk of sPTB compared to patients with UCA < 95°. This suggests that the UCA seems to be a better predictor of sPTB than the cervical length in patients receiving pessary treatment.

Changes of uterocervical angle and cervical length in early and mid-pregnancy and their value in predicting spontaneous preterm birth

Objective: To explore the feasibility of transvaginal ultrasound measurement of uterocervical angle (UCA) and cervical length (CL) in early and mid-pregnancy and evaluate their combined prediction of spontaneous preterm birth (sPTB) in singleton pregnancies. Patients and Methods: This retrospective study comprised 274 pregnant women who underwent transvaginal ultrasound measurement of CL in mid-pregnancy (15-23+6 weeks); in 75 among them, CL also had been measured in early-pregnancy (<14 weeks). These 274 pregnant women were further divided into a preterm group (n = 149, <37 weeks gestation) and a control group (n = 125, >37 weeks gestation) according to delivery before or after 37 weeks, respectively. In the preterm group, 35 patients delivered before 34 weeks and the remaining 114 delivered between 34 and 37 weeks. Results: The optimal threshold of CL to predict preterm birth risk in women with <37 weeks gestation was 3.38 cm, and the optimal threshold of the UCA to predict preterm birth risk in the same group of women was 96°. The optimal threshold of CL to predict preterm birth risk in women with <34 weeks gestation was 2.54 cm, while that of the UCA in the same group of patients was 106°. The area under the curve for predicting preterm birth by combining the UCA and CL measurements was greater than that by using the UCA or CL alone (p < 0.01). The sensitivity and specificity for predicting preterm birth at <34 weeks gestation was 71.7% and 86.4%, respectively; and the sensitivity and specificity for predicting preterm birth at <37 weeks gestation was 87.6% and 80.6%, respectively. The difference between the two groups in CL and UCA were not significant in early pregnancy (p > 0.01), but only in mid-pregnancy (p < 0.01). There was a negative correlation between UCA and gestational week at delivery (r = -0.361, p < 0.001) and a positive correlation between CL and gestational week at delivery (r = 0.346, p < 0.001) in mid-pregnancy. The proportion of deliveries at <34 weeks was highest when the UCA was >105°, and the proportion of deliveries between 35 and 37 weeks was highest when the UCA was between 95° and 105°. The proportion of deliveries at <34 weeks was highest when the CL was <2.5 cm. Conclusion: The combination of UCA and CL has a better ability to predict preterm birth than either measurement alone. A more obtuse UCA or a shorter CL is associated with an earlier spontaneous preterm birth. The UCA increases from early to mid-pregnancy, while the CL decreases from early to mid-pregnancy.

Value of post-cerclage transvaginal ultrasound in predicting preterm birth at <28 weeks in twin pregnancy with ultrasound-indicated cerclage

OBJECTIVE

To evaluate the value of transvaginal ultrasound parameters before and after cerclage in twins in predicting spontaneous preterm birth (sPTB) before 28+0 weeks.

METHODS

We retrospectively studied the medical records of twin-pregnant women who underwent ultrasound-indicated cerclage between January 2016 and February 2022 at our hospital. Recorded transvaginal ultrasound images before and after cerclage were reassessed for cervical length (CL), uterocervical angle (UCA), funneling, and sludge. Multivariate logistic and Cox regression analyses were performed to identify the independent risk factors associated with sPTB before 28 weeks.

RESULTS

A total of 69 women were included. Among them, 17 women (24.64%) delivered before 28 weeks of age. Regression analysis revealed a significant association of post-cerclage CL, UCA, white blood cell (WBC) count, and gestational age (GA) at cerclage with sPTB before 28 weeks. The area under the curve of these predictors was 0.938 (95% confidence interval, 0.882-0.994; p < .001), with a sensitivity of 88.2%, specificity of 92.3%, positive predictive value of 78.9%, and negative predictive value of 96.0%. Cox analysis showed that post-cerclage UCA was an independent risk factor affecting the cerclage-to-delivery interval (hazard ratios, 1.026; 95% confidence interval (CI), 1.004-1.048; p = .019).

CONCLUSIONS

The combination of post-cerclage CL, UCA, WBC count, and GA at cerclage showed good performance in predicting sPTB at <28 weeks in twin pregnancy. Post-cerclage UCA is also associated with pregnancy latency. We found that post-cerclage cervical ultrasound may be useful to predict preterm birth before 28 weeks in twins who undergo ultrasound-indicated cerclage.

Uterocervical angle versus cervical length in the prediction of spontaneous preterm birth in women with history of spontaneous preterm birth: a prospective observational study

BACKGROUND

Preterm delivery is a leading cause of neonatal mortality and morbidity. History of spontaneous preterm birth is the greatest risk factor for another preterm delivery. So, every effort should be made to prevent the recurrence of preterm delivery in this vulnerable group. This study aimed to evaluate the predictive ability of the anterior uterocervical angle and cervical length in preterm birth.

PATIENTS AND METHODS

This was a prospective cohort study that included 70 patients with a history of spontaneous preterm birth. Ultrasound measurements of cervical length and anterior uterocervical angle were set to be measured for each patient at three visits; first between 16 0/7 and 24 0/7 weeks, second between 24 1/7 and 32 0/7 weeks, and the third was between 32 1/7 and 36 6/7 weeks. The correlation between both measures and the prediction of preterm birth among study participants was the primary outcome of the study. Neonatal outcome among the study patients was a secondary measure of outcome.

RESULTS

The incidence of preterm birth among study participants was 31.41%. Cervical length and uterocervical angle showed progressive decrease and increase respectively throughout pregnancy. At the 2nd visit, the two measures were significantly different between those who delivered at term and those with preterm delivery with the cervical length being significantly shorter in the preterm arm (3.0 ± 0.49 versus 3.38 ± 0.36, p < 0.001) and uterocervical angle being significantly bigger among the same arm (110.1 ± 18.48 versus 84.42 ± 12.24, p < 0.001). A uterocervical angle > 89.8° at the second visit predicted preterm birth with 81.8% sensitivity and 70.8% specificity while cervical length ≤ 3.22 cm at the second visit predicted preterm birth with 68.1% sensitivity and 62.5% specificity. Multivariant logistic regression analysis showed that uterocervical angle > 89.8° at the second visit increased the odds ratio for preterm birth by 9.

CONCLUSION

Uterocervical angle can be a useful ultrasound marker for the prediction of preterm birth among high risk patients. A cutoff value of 89.8° can be used as a threshold above which prophylactic measures such as cervical cerclage or progesterone therapy can be provided.

TRIAL REGISTRATION

NCT05632003 (First posted date: 30/11/2022).

Uterocervical angle in predicting spontaneous preterm birth: a systematic review and meta-analysis

OBJECTIVE

This study aimed to compare the uterocervical angles in term and spontaneous preterm birth cohorts and to compare the test characteristics of the uterocervical angle and cervical length in the prediction of spontaneous preterm birth.

DATA SOURCES

A systematic search of published literature from January 1, 1945, to May 15, 2022, was performed using the following databases: PubMed, Cochrane Central Register of Controlled Trials, Embase, World Health Organization International Clinical Trials Registry Platform, Web of Science, and ClinicalTrials.gov. The search was not restricted. The references of all relevant articles were reviewed.

STUDY ELIGIBILITY CRITERIA

Randomized control trials, nonrandomized control trials, and observational studies were evaluated for primary comparisons. Included studies compared the uterocervical angles in term and spontaneous preterm birth cohorts and compared the uterocervical angle with cervical length in the prediction of spontaneous preterm birth.

METHODS

Of note, 2 researchers independently selected studies and evaluated the risk of bias with the Newcastle-Ottawa Scale for cohort and case-control studies. Mean differences and odds ratios were calculated using a random effects model for inclusion and methodological quality. The primary outcomes were uterocervical angle and successful prediction of spontaneous preterm birth. Moreover, posthoc analysis comparing the uterocervical angle and cervical length together was performed.

RESULTS

A total of 15 cohort studies with 6218 patients were included. The uterocervical angle was larger in the spontaneous preterm birth cohorts (mean difference, 13.76; 95% confidence interval, 10.61-16.91; P<.00001; I²=90%). Sensitivity and specificity analyses demonstrated lower sensitivities with cervical length alone and uterocervical angle plus cervical length than with uterocervical angle alone. Pooled sensitivities for uterocervical angle and cervical length alone were 0.70 (95% confidence interval, 0.66-0.73; I²=90%) and 0.46 (95% confidence interval, 0.42-0.49; I²=96%), respectively. Pooled specificities for uterocervical angle and cervical length were 0.67 (95% confidence interval, 0.66-0.68; I²=97%) and 0.90 (95% confidence interval, 0.89-0.91; I²=99%), respectively. The areas under the curve for uterocervical angle and cervical length were 0.77 and 0.82, respectively.

CONCLUSION

Uterocervical angle alone or with cervical length was not superior to cervical length alone in predicting spontaneous preterm birth.