Comparison of ultrasonographic cervical length and the Bishop score in predicting successful labor induction

BACKGROUND: The aim of this study was to compare the performance of the Bishop score and transvaginal ultrasonography to predict successful labor induction, and to estimate the most useful cut-off points for the two methods. METHODS: The five components of the Bishop score were assessed by digital examination and cervical length was measured by transvaginal ultrasonography in 177 women with a single pregnancy, 36-42 weeks of gestation, and a live fetus in cephalic presentation before induction of labor. RESULTS: Multiple regression analysis showed that the Bishop score, cervical length, and parity provided independent contribution in the prediction of the likelihood of delivering vaginally within 60 h. The only component of the Bishop score that was independently predictive of the probability of vaginal delivery within 60 h was station. The best cut-off points for predicting successful induction using receiver operating characteristic curves were 24 mm for cervical length and 4 for the Bishop score. Cervical length was a better predictor than the Bishop score (sensitivity and specificity of 66 and 77% versus 77 and 56%, respectively). Kaplan-Meier survival curves showed that cervical length was the best discriminator of successful induction. CONCLUSION: Measurement of cervical length by transvaginal ultrasonography is a better predictor of success in labor induction with both topical prostaglandin and oxytocin.     

Ultrasound and clinical predictors for Caesarean delivery after labour induction at term

OBJECTIVE: To assess the relationship of ultrasound assessment for amniotic fluid, fetal weight, cervical length, cervical funneling and clinical factors on the risk of Caesarean delivery after labour induction at term. METHODS: On hundred and fifty-two women scheduled for labour induction at term agreed to participate. Sonography was performed to obtain fetal biometry, amniotic fluid index and cervical length and to detect funneling at the internal cervical os. The sonographic findings were concealed. Study women received standard care during labour induction. RESULTS: On univariate analysis using Fisher's exact test, parity, cervical length and Bishop score were associated with Caesarean delivery. Following multivariable logistic regression analysis, only nulliparity (adjusted odds ratio (AOR) 5.2 (95% CI 2.2-12.2): P<0.001) and transvaginal ultrasound-determined cervical length of more than 20 mm (AOR 2.8 (95% CI 1.0-7.4): P=0.04) were independent predictors of Caesarean delivery in labour induction. Maternal age, maternal height, gestational age, indication for labour induction, amniotic fluid index, cervical funneling and ultrasound-estimated fetal weight did not predict Caesarean delivery. CONCLUSION: In women who had undergone labour induction at term with a singleton fetus, nulliparity and cervical length of more than 20 mm on transvaginal sonography were independent predictors of Caesarean delivery. This information is helpful for pre-induction counselling.     

Comparison between subjective and objective assessments of the cervix before induction of labour.

The aim of the study was to compare the pre-induction cervical assessment by Bishop's score with the transvaginal ultrasound cervical length as predictors of the induction-delivery interval (IDI) and the success of induction. This prospective study included 104 women with singleton pregnancies who were booked for induction of labour at term over a period of 3 years. Transvaginal ultrasound measurement of the cervical length and Bishop's Score were performed by different operators. Data were collected on parity, gestational age, methods of induction, Bishop's score, ultrasound cervical length measurements, IDI and mode of delivery. A total of 87 women (83.7%) delivered vaginally and 17 (16.3%) delivered by caesarean section. Linear regression models demonstrated that ultrasound cervical length was a better indicator of IDI than Bishop's score. The adjusted R2 for the regression including ultrasound cervical length was 0.87 compared with a value of 0.67 for the model including Bishop's score. Although logistic regression analysis confirmed that cervical effacement was the best component of Bishop's score to predict the mode of delivery, ultrasound cervical length assessment provided better prediction. Receiver operating characteristic curve showed that the optimised cut-off value for prediction of vaginal delivery was < or =3.4 cm for the cervical length and >5 for the Bishop's score. At those optimised cut-off values the cervical length predicted vaginal delivery with sensitivity of 62.1% (95% CI [51%, 72.3%]) and specificity of 100% (95% CI [80.5%, 100%]) while the Bishop's score predicted vaginal delivery with a sensitivity of 23% (95% CI [14.6%, 33.2%]) and specificity of 88.2% (95% CI [63.5%, 98.5%]). Further analysis showed that ultrasound cervical length has a higher sensitivity in prediction of vaginal delivery in multiparous than nulliparous women (85.1% compared with 35%) at a cut-off value of < or =3.4 cm. On the other hand, it has a higher sensitivity in nulliparous comparable with multiparous women (85.3% compared with 30%) in prediction of IDI at a cut-off value of >3.5 cm. In conclusion, transvaginal ultrasound cervical length assessment is better than Bishop's score in predicting the IDI and the success of induction of labour.     

Comparison of digital and ultrasonographic examination of the cervix in predicting time interval from induction to delivery in women with a low Bishop score

OBJECTIVE: To compare pre-induction ultrasonographic cervical length and Bishop score in predicting time to delivery after labour induction with prostaglandins. DESIGN: Prognostic cohort study. SETTING: Tertiary referral maternity unit in a teaching hospital. POPULATION: Two hundred and sixty-six women with singleton pregnancies at between 34(+0) and 41(+3) weeks of gestation requiring induction of labour with prostaglandins for medical indications. METHODS: A secondary analysis of a trial comparing two prostaglandins. Assessment of the Bishop score and measurement of the cervical length by transvaginal sonography were performed by two operators, blinded to each other's results. We estimated the predictive effects on the outcomes of ultrasonographic cervical length and Bishop score. MAIN OUTCOME MEASURE: Time intervals from induction to delivery and to vaginal delivery. RESULTS: Cervical length and Bishop score were associated with the time interval from induction to delivery, based on univariable analyses. When considered jointly in a multivariable model, only the Bishop score was significantly related to the outcome: The higher the Bishop score, the higher the hazard to delivery [hazard ratio (HR): 1.2, 95% confidence interval (CI): 1.1-1.3], illustrating that once the Bishop score is taken into account, further knowledge of cervical ultrasound length (HR: 0.99, 95% CI: 0.98-1.0) did not add any predictive information. Also, Bishop score was predictive of time interval between induction and vaginal delivery (HR: 1.2, 95% CI: 1.1-1.4) while cervical length had no additional predictive value (HR: 0.99, 95% CI: 0.98-1.0) when both cervical length and Bishop score were introduced in the model. CONCLUSIONS: The Bishop score appears to be a better predictor of the time interval from induction to delivery and to vaginal delivery than cervical length after induction of labour for medical reasons.     

Sonographic cervical length as a predictor of type of delivery after induced labor

Purpose

This study was undertaken to evaluate the comparative value of sonographic cervical length and the Bishop score in predicting the type of delivery after induced labor.

Methods

The Bishop score was determined by digital examination and cervical length by transvaginal sonography in 177 women.

Results

The best cut-off points for predicting type of delivery found with ROC curves were 25.2?mm for cervical length and 5 for the Bishop score. The Bishop score was not predictive of type of delivery. Cervical length was related to type of delivery in women with Bishop score ≤5. A logistic regression model showed that only cervical length ≥25.2?mm, parity, and body mass index significantly predicted the likelihood of cesarean delivery.

Conclusions

Our study suggests that both Bishop score and sonographic cervical length can contribute to predicting type of delivery after labor induction, but cervical length is a better predictor of the risk of cesarean delivery.     

Preinduction cervical assessment by Bishop's score and transvaginal ultrasound

In this pilot study, 50 patients underwent preinduction cervical assessment by digital Bishop Score (BS) and transvaginal ultrasonography. The BS was lower in 7 patients requiring caesarean section than in 43 delivered vaginally (P = 0.017). Of seven ultrasound parameters examined, six (cervical length, width, dilatation, application and position and lower segment thickness) were similar in both groups. Cervical angle, however, was more acute in those delivered abdominally than vaginally (median = 60 degrees and 90 degrees, respectively, P = 0.002). Posterior cervical angle was more accurate than BS in predicting vaginal delivery (Kappa = 0.48 versus 0.21). Patient discomfort was significantly less with transvaginal ultrasound than digital examination. Combining posterior cervical angle greater than 70 degrees and BS greater than 5 yielded the best accuracy in predicting successful induction of labour (sensitivity = 88%, specificity = 100%, Kappa = 0.68).     

Comparison of pre-induction ultrasonographic cervical length and Bishop score in predicting risk of cesarean section after labor induction with prostaglandins

OBJECTIVE: To compare pre-induction ultrasonographic cervical length and Bishop score in predicting risk of caesarean section after labor induction with prostaglandins. PATIENTS AND METHODS: Assessment of the Bishop score and measurement of the cervical length by transvaginal sonography were performed by two operators, blinded to each other's results among women with singleton pregnancies at between 34(+0) - 41(+3) weeks of gestation requiring induction of labor with prostaglandins for medical indications. Fisher's exact test and regression logistic models were used for statistics analysis. In order to measure the strength of the association between ultrasonographic cervical length or Bishop score on one hand, and the caesarean sections rate (global or for failed induction or failure to progress) on the other hand, we computed odds ratios with 95% confidence interval. RESULTS: Among the 266 patients included in the study, multivariate analysis has shown that only Bishop score was predictive for the global caesarean section risk (OR [95% CI] 0.63 [0.45-0.87] ; P =0.005). However, neither Bishop score (OR [95% CI] 0.68 [0.42-1.09] ; P =0.11), nor ultrasonographic cervical length (OR [95% CI] 1.01 [0.95-1.08] ; P =0.59) was predictive for failed induction or failure to progress caesarean section risk. DISCUSSION AND CONCLUSION: The Bishop score appears to be a better predictor of the global caesarean section risk than ultrasonographic cervical length after induction of labor for medical reasons.     

Transvaginal sonographic assessment of cervix in prediction of admission to delivery interval in preterm premature rupture of membranes

Objective: To assess the usefulness of cervical parameters measured by transvaginal sonography, that is, cervical length and posterior cervical angle, in predicting the admission to delivery interval in women with preterm rupture of membranes.

Methods: This prospective study was conducted in a tertiary care centre in South India. Women with preterm premature rupture of membranes at 28–34 weeks, confirmed clinically, not in labour and presenting within 24?hours to hospital were included. We evaluated the relationship between latency interval and transvaginal sonographic parameters (cervical length and posterior cervical angle), parity, age, Amniotic Fluid Index (AFI), total leucocyte count at admission using Cox proportional hazards model.

Results: Mean time interval between the membrane rupture and delivery was 96.9?h. Majority of the women (63.8% (n?=?51)) delivered within 48?hours. Transvaginal sonographic cervical length was not shown to be associated with latency interval (p?=?.559), whereas. Posterior cervical angle was shown to be significantly associated with the interval (hazard ratio 1.03, 95%CI: 1.01–1.06; p?=?.003)

Conclusions: Posterior cervical angle assessment using transvaginal sonography is an useful tool in the assessing the latency interval in women with preterm premature rupture of membranes (PPROM). This could help in counselling and planning timely referral to centres with neonatal facilities.     

Sonographic cervical length measurement before labor induction in term nulliparous women

OBJECTIVE: The purpose of the study was to determine if transvaginal sonographic measurement of the cervical length is a useful method to predict successful labor induction in nulliparas. METHODS: 137 women who were scheduled for medically indicated induction of labor had a transvaginal sonographic measurement of the cervical length before labor induction. Inclusion criteria were: (1) singleton pregnancy; (2) gestational age between 37-42 weeks; (3) live fetus in cephalic presentation; (4) intact membranes; (5) no vaginal bleeding; (6) no previous history of uterine surgery; (7) nulliparous women, and (8) no allergy or asthma in response to prostaglandins. Induction of labor was performed within 6 h of the ultrasonographic examination, by inserting 2 mg of dinoprostone in the posterior vaginal fornix, repeated if needed every 6 h for up to three doses. When the cervix became favorable and no regular contractions were observed, amniotomy and oxytocin augmentation, starting at 1 mIU/min and increasing 1 mIU every 30 min as necessary, was performed. RESULTS: All women were Caucasians and the mean age was 24.3 years (range 19-37 years). The mean cervical length was 28 mm (range 11-39 mm). The Bishop score was < or =5 in 101 women and >5 in the 36 others. Vaginal delivery occurred in 92 women (67.1%), and the vast majority of them (89 women; 96.7%) gave birth within 24 h of induction. Forty-five women (32.8%) had a cesarean section. The Bishop score was not predictive of the mode of delivery. Thirty-six of 101 women (35.6%) with a Bishop score < or =5 delivered by cesarean section, compared to 9 of 36 women with a Bishop score >5 (25%) (p = NS). Women with a cervical length <27 mm were more likely to deliver vaginally. Using this cutoff value the sensitivity of a successful labor induction was 76% and the specificity was 75.5%. CONCLUSIONS: Transvaginal sonographic measurement of cervical length is a good predictor of a successful labor induction at term in nulliparas.     

Digital and transvaginal ultrasound cervical assessment for prediction of successful labor induction.

OBJECTIVE: To compare the values of preinduction transvaginal cervical length measurements and Bishop score to predict successful labor induction. METHODS: A prospective, observational trial of nulliparous women undergoing labor induction. Inclusion criteria were gestational age between 36 and 42 weeks, singleton cephalic presentation of the fetus, and intact membranes. Preinduction cervical ripening was performed using 25 microg intravaginal misoprostol (PGE1), repeated every 4 h, up to a maximum of 3 doses. Induction was subsequently continued by oxytocin and amniotomy. RESULTS: A total of 43 women met the inclusion criteria. Mean preinduction cervical length for women with successful or failed labor induction was 26 mm (95% Confidence interval [CI], 27-32) and 34 mm (95% CI, 33-38), respectively (P=0.002). Mean Bishop scores for successful and failed induction groups were 5.4 (95% CI, 5.2-6.2) and 3.1 (95% CI, 2.8-3.5), respectively (P=0.003). CONCLUSION: Digital examination and transvaginal ultrasound of the cervix predict successful labor induction with reasonable accuracy.     

Comparison of Cervical Length Measured by Transvaginal Ultrasonography and Bishop Score in Predicting Response to Labor Induction

Background

This study aims to compare the value of the Bishop score and cervical length measurement by transvaginal ultrasonography in predicting active labor within 6 h, induction-to-delivery interval, and the duration of active labor and to estimate the most useful cutoff points for the two methods.

Methods

This is a prospective comparative study of Bishop score and cervical length measured by transvaginal sonography on 62 nulliparous subjects who underwent induction of labor.

Results

The Bishop score of the subjects ranged from two to seven (2–7). The mean Bishop in this study population was 4.37 + 1.23. The mean cervical length in this study was 25.59 + 6.07. Bishop score was highly significant (P value < 0.0001) in predicting active phase of labor as compared to cervical length (P = 0.004). The best cutoff value for Bishop score to predict induction of labor within 6 h was more than 4 with sensitivity of 69% and specificity of 79%. Similarly, best cutoff value for cervical length to predict induction of labor within 6 h was less than or equal to 25 mm with sensitivity of 51% and specificity of 70%. Bishop score was more significant (P = 0.001) in predicting induction-to-delivery interval within 12 h as compared to cervical length (P = 0.01).

Conclusion

The Bishop score was superior in predicting the response to induction as compared to the cervical length measured by transvaginal ultrasonography.

     

Can measurement of cervical length,fetal head position and posterior cervical angle be an alternative method to Bishop score in the prediction of successful labor induction?

Aim: The purpose of this study was to evaluate sonographic cervical length, posterior cervical angle and fetal head position in predicting successful induction of labor at term can be an alternative method to Bishop score.

Methods: This prospective observational study recruited 223 women with singleton gestations scheduled for induction of labor at 37–42 weeks. Parity, body mass index, Bishop score, fetal head position, cervical angle measurement and cervical length was investigated to predict successful labor induction. Multiple regression analysis was performed to determine the parameters in the prediction of successful vaginal delivery within 24 hours.

Results: Forty-five patients were excluded because of cesarean section performed for other reasons than arrest of dilation or fetal head descent (43 fetal distress, 2 cord prolapsus). Remaining 178 patients were divided into two groups according to duration of delivery time. 139 patients delivered within 24 hours were classified as group I, 39 patients delivered after 24 hours were classified as group II. Percentage of multiparity was statistically significantly higher in group I than in group II [59 (42.4%), 9 (23.0%) respectively, p?=?0.009]. Cervical length was statistically significantly shorter in group I than in group II [23.1?±?7.42?mm, 31.3?±?6.83?mm respectively, p?<?0.001]. Bishop score was statistically significantly higher in group I than in group II [3 (1–4), 1 (1–4) respectively, p?<?0.001]. Posterior cervical angle was statistically significantly higher in group I than in group II [100.1?±?17.2, 92.7?±?21.4 respectively, p?=?0.007]. According to the fetal head position, there was no statistically significant difference in labor duration between the groups (p?=?0.787). In the multivariate regression analysis of variables, multiparity, cervical length and Bishop score were statistically significantly predictive in successful labor induction.

Conclusion: Multiparity status, cervical length, posterior cervical angle and Bishop score can predict successful labor induction, but fetal head position is not predictive in successful labor induction.     

Unsucessful labour induction in women with unfavourable cervical scores: predictors and management

BACKGROUND: Misoprostol fails to induce labour in 5-20% of women at term. AIM: To analyse possible predictors of unsuccessful induction with 50 microg vaginal misoprostol and effectiveness and the safety of intracervical Foley catheter application in induction failures. METHODS: An observational study was conducted on 1030 women with singleton, live fetuses, vertex presentation, > 34 weeks of gestation and Bishop score < 5. Induction of labour with 50 microg vaginal misoprostol repeated every 6 h was attempted. Women without regular uterine contractions and cervical changes at the end of 24 h were considered to be unsuccessful, and a transcervical Foley balloon catheter was placed and inflated with 50 mL saline. Possible predictors of induction failures were analysed via logistic regression analysis. Neonatal outcomes and vaginal delivery achieved after Foley catheter were also determined. RESULTS: Induction was successful in 918 cases (89.1%) and Foley catheter was placed in 112 (10.8%) women. Increasing gestational age in weeks (odds ratio [OR] 0.77, 95% confidence interval [CI] 0.68-0.88) and increasing Bishop score (OR 0.73, 95% CI 0.60-0.90) decreased the risk of failed induction. Failure rates were 16% (27/169) in post-term nulliparous women with Bishop score 相似文献   

A new objective scoring system for the prediction of successful induction of labour

A prospective study was done in 311 women undergoing induction of labour for the formulation of a new score, which will be more objective than the conventional Bishop's score. Pre-induction cervical assessment was done by the transvaginal sonographic parameters followed by the digital examination. Labour induction was successful in 79.09%. A new score was formulated using the parameters having independent association and weighting of individual components was given according to its regression coefficients. A new score with a maximum value of 13 was proposed. The best cut-off point for the new score in receiver operating characteristics curve was six with a sensitivity of 95.5% and specificity of 84.6%. The new score was found to have a better area under the curve than the conventional score.     

The labor induction: integrated clinical and sonographic variables that predict the outcome.

OBJECTIVE: To analyze the clinical and sonographic variables that predicts the success of labor induction. STUDY DESIGN: We studied the Bishop score, cervical length and parity in 196 pregnant women in the prediction of successful vaginal delivery within 24 h of induction. Logistic regression and segmentation analysis were performed. RESULTS: Cervical length (odds ratio (OR) 1.089, P<0.001), Bishop score (OR 0.751, P=0.001) and parity (OR 4.7, P<0.001) predict the success of labor induction. In a global analysis of the variables studied, the best statistic sequence that predicts the labor induction was found when we introduced parity in the first place. The success of labor induction in nulliparous was 50.8 and 83.3% in multiparous women (P=0.0001). CONCLUSIONS: Cervical length, Bishop score and parity, integrated in a flow chart, provide independent prediction of vaginal delivery within 24 h of induction.     

Variables that predict the success of labor induction

BACKGROUND. To analyze the clinical and sonographic variables that affect the success of labor induction. METHODS. Bishop score, cervical length, and parity were studied in 196 pregnant women in the prediction of successful vaginal delivery within 24 hr of induction. Logistic regression and segmentation analysis were performed. RESULTS. Cervical length [odds ratio (OR) 1.089, P<0.001], Bishop score (OR 0.751, P=0.001), and parity (OR 6.85, P<0.001) predict the success of labor induction. The best cut-off points for cervical length were <16.5, 16.5--27, and >27 mm (P=0.0016). In the analysis of the Bishop score, we also obtained three discriminatory points, 0, 1--4, and >4 (P=0.0006), that best predict the labor induction. Finally, in a global analysis of the variables studied, the best statistic sequence that predicts the labor induction was found when we introduced parity in the first place. The success of labor induction in nulliparous was 50.77 and 83.33% in multiparous (P=0.0001). CONCLUSIONS. Cervical length, Bishop score, and parity predict the success of labor induction.     

Comparison of the Bishop score, body mass index and transvaginal cervical length in predicting the success of labor induction

Purpose  To evaluate the role of ultrasonographic and various maternal and fetal parameters in predicting successful labor induction. Methods  Body mass index, cervical length, dilatation, effacement, Bishop score, parity, maternal age and birth weight were evaluated in 189 singleton pregnant women at 37–42 weeks of gestation and having induction of labor. All underwent induction of labor with oxytocin. Body mass index was calculated using the formula weight (kg)/height² (m), cervical measurement was performed by transvaginal ultrasonography and Bishop score was determined by digital examination of cervix. Results  Logistic regression analysis indicated that the cervical length and body mass index were independent variables in determining the risk of cesarean section (OR = 1.206, P = 0.000, CI 95% = 1.117–1.303; OR = 1.223, P = 0.007, CI 95% = 1.058–1.414 respectively). In multiple linear regression analysis, the effect of cervical length and body mass index on induction delivery interval was found to be statistically significant (t = 5.738, P = 0.000; t = 2.680, P = 0.009, respectively). ROC curve showed that the best parameter in predicting the risk of cesarean section was cervical length and that cervical length and body mass index were better parameters compared to the Bishop score (the areas under the curve are 0.819, 0.701 and 0.416, respectively). Conclusions  Body mass index and transvaginal cervical length were better predictors compared to the Bishop score in determining the success of labor induction.     

A way to lend objectivity to Bishop score.

The aim of this study was to explore the possibility of utilising pre-induction cervical length assessment by trans-vaginal ultrasound to improve the predictive value of the Bishop score. The idea of this paper has evolved following our prospective study, which was designed to compare the pre-induction objective assessment of the cervix by ultrasound with the subjective one by Bishop Score. The Bishop scores of the 104 women included in the study were modified by replacing the digital assessment of the cervical length by ultrasound cervical length measurements. There was a significant statistical difference (p < 0.0001) between the median of the original and the modified Bishop scores. The original Bishop score showed insignificant association (p > 0.05) with the induction-delivery interval (IDI) and the mode of delivery while the modified score showed a significant association (r = 0.31, p < 0.05) with mode of delivery and a highly significant one (r = 0.55, p < 0.0001) with the IDI. The receiver operating characteristic curve showed that the optimised cut-off value for prediction of vaginal delivery was >5 for the original Bishop Score and >3 for the modified one. At those optimised cut-off values, the original Bishop Score predicted vaginal delivery with a sensitivity of 23% (95% CI; 14.6%, 33.2%) and specificity of 88.2% (95% CI; 63.5%, 98.5% while the modified Bishop score predicted vaginal delivery with a sensitivity of 62% [95%; CI 51 - 72.3] and specificity of 82% [95%; CI 56.6 - 96]). In conclusion, the modified Bishop score is better than the original one in predicting the IDI and the success of induction of labour. The sensitivity of the Bishop score in predicting the rate of vaginal delivery has been improved significantly following the modification.     

Transvaginal ultrasonography of the uterine cervix before induction of labor]

OBJECTIVE: To compare the Bishop score and transvaginal ultrasonographic measurement of cervical length for predicting the mode of delivery following medically indicated induction of labor in term patients. METHOD: The study was conducted prospectively among 134 women who required medically indicated induction of labor. Inclusion criteria were singleton pregnancy, gestational age > or = 37 weeks of amenorrhea, cephalic presentation, and intact fetal membranes. Transvaginal ultrasonography was performed for measurement of the cervical length but the patients were managed without considering this parameter. A receiver-operating characteristic curve was constructed to determine the best cut-of value of cervical length for predicting the risk of cesarean section following induction of labor. RESULTS: Thirty six patients (26.9%) underwent cesarean section and cervical dilatation at time of the cesarean section was < 8 cm in 25 cases. The Bishop score was not predictive for the mode of delivery in this study. In contrast, the cesarean section rate was significantly lower in women with a uterine cervix < 26 mm (18.9 vs 36.6%, p = 0.02). Moreover, the difference has concerned only the cesarean sections performed before 8 cm dilatation (9.5 vs 30.0%, p = 0.002). CONCLUSION: Cervical length measured with transvaginal ultrasonography is a better predictor than the Bishop score for predicting the risk of cesarean section following medically indicated induction of labor.     

Transvaginal ultrasonographic cervical measurement as a predictor of successful labor induction

OBJECTIVE: Our purpose was to compare transvaginal cervical measurement and the Bishop score as indicators of duration of labor and successful induction of labor at term.Study Design: This prospective observational study recruited women with singleton gestations scheduled for induction of labor at > or =37 weeks. Transvaginal ultrasonographic measurement of cervical length was performed and the Bishop score was determined, each by operators masked to the other measurement. Data were collected on parity, gestational age, mode of delivery, induction agent, induction-to-delivery interval, Bishop score, and cervical length measurement. RESULTS: A total of 77 women were analyzed. Vaginal delivery occurred in 69%. Both Bishop score and cervical length showed linear correlation with duration of labor (R(2) = 0.43, P <. 001; R(2) = 0.48, P <.001; respectively). Women with cervical length <3.0 cm had shorter labors (P <.001) and were more likely to be delivered vaginally (P <.001). Women with a Bishop score >4 also had shorter labors and were more likely to be delivered vaginally, with similar P values. A logistic regression model identified cervical length and parity as the only independent predictors of vaginal delivery. CONCLUSIONS: Both ultrasonographically measured cervical length and Bishop score predict duration of labor and likelihood of vaginal delivery. However, only cervical length and parity were independent predictors of mode of delivery.