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

The predictive value of transvaginal cervical length and cervical angle ultrasonography in term delivery outcomes: a cohort study

BACKGROUND

Various techniques have been proposed to predict and evaluate the timing and conditions of childbirth in pregnant women at different stages of pregnancy. Providing precise methods for forecasting childbirth status can reduce the burden on the healthcare system. This study aimed to evaluate the predictive value of transvaginal sonography of cervical length (CL) and cervical angle (CA) on full-term delivery outcomes.

METHODS

This cohort study analyzed 151 pregnant women between 37 and 42 weeks of gestational age who were treated at Rasoul Akram Hospital affiliated with Iran University of Medical Sciences from June 2023 to January 2024. All Participants received transvaginal examinations. This study evaluated the accuracy of CL and CA by transvaginal sonography in predicting outcomes like vaginal delivery, cesarean section, necessity for labor induction, and the rate of Premature Rupture of Membranes (PROM). The study used the Receiver Operating Characteristic (ROC) curve to determine the optimal cutoff for predicting birth outcomes.

RESULTS

The mean age of the pregnant women was 28.9 ± 4.22 years, while the average duration of pregnancy was 39.8 ± 2.11 weeks. Cesarean delivery was performed on 45 individuals (29.8%) and 106 (70.1%) underwent vaginal delivery. The mean CL overall stood at 21.2 ± 6.4 mm. PROM was observed in 41 cases (27.1%) among full-term pregnancies. A significant difference was noted in mean CL between the cesarean and vaginal delivery groups (24.2 ± 2.4 vs. 20.1 ± 2.1 mm, p = 0.001). The predictive value of a CL measuring 21 mm for cesarean delivery was 72.2% sensitive and 79.1% specific. Similarly, a CL of 22 mm showed 66.6% sensitivity and 80.2% specificity for labor induction. Regarding PROM in full-term pregnancies, a CL assessment demonstrated 59.8% sensitivity and 69.1% specificity. Finally, a CA of 115.2° exhibited 70.3% sensitivity and 78.4% specificity in predicting vaginal delivery.

CONCLUSION

The present study showed that evaluating CL and CA via transvaginal sonography demonstrated adequate diagnostic accuracy in predicting spontaneous birth, need for labor induction, cesarean delivery, and incidence of PROM in full-term pregnant women. This method is suggested to be an accurate and appropriate way to predict delivery results.

Cervical elastography using E-Cervix™ for prediction of preterm birth in twin pregnancies with threatened preterm labor

OBJECTIVE

To evaluate the prediction performance of E-Cervix™ for preterm birth in twin pregnancies with threatened preterm labor.

METHODS

This was a single-center retrospective cohort study of twin pregnancies presenting to obstetrics triage for threatened preterm labor (PTL) between 23 0/7 - 33 6/7 weeks who received screening for PTL with transvaginal ultrasound cervical length (TVU CL) and cervical elastography with E-Cervix™ at the time of triage. Cervical elastography parameters were examined and compared between women who delivered preterm and those who did not. The quantification of cervical strain was calculated by a data analysis system that directly analyzes raw data from the region of interest (ROI) and described as hardness ratio (HR), mean strain level within 1 cm from internal (IOS) and external (EOS) os.

RESULTS

63 twin gestations without prior preterm birth and with threatened PTL between 23 0/7 - 33 6/7 weeks of gestation were included in the study. 27 (42.9 %) had cervical length < 25 mm, and were admitted for true PLT. Out of the 36 women with cervical length ≥ 25 mm, 6 (16.7 %) were admitted. Women with threatened PTL had significantly higher HR compared to those with true PTL (p < 0.01), and significantly lower IOS and EOS. Women who delivered preterm had significantly higher HR compared to those who did not delivery preterm and significantly lower IOS and EOS, in overall cohort, and in the subset of women with true PTL. Incidences of HR < 50 % and < 35 % were statistically significantly higher in women who delivered preterm compared to those who did not (p < 0.01).

CONCLUSION

Cervical elastography with E-Cervix™ may be useful for assessment of twin gestations presenting to obstetrics triage for threatened PTL.

Randomized trial of screening for preterm birth in low-risk women - the preterm birth screening study

BACKGROUND

Preterm birth is a major cause of perinatal morbidity and mortality. It is unclear whether the introduction of a universal transvaginal ultrasound cervical length screening program in women at low risk for preterm delivery is associated with a reduction in the frequency of preterm birth.

OBJECTIVE

To test the hypothesis that the introduction of a midtrimester universal transvaginal ultrasound cervical length screening program in asymptomatic singleton pregnancies without prior preterm delivery would reduce the rate of preterm birth at <37 weeks of gestation.

STUDY DESIGN

This study was a multicenter nonblinded randomized trial of screening of asymptomatic singleton pregnancies without prior spontaneous preterm birth, who were randomized to either cervical length screening program (ie, intervention group) or no screening (ie, control group). Participants were randomized at the time of their routine anatomy scan between 18 0/7 and 23 6/7 weeks of gestation. Women randomized in the screening group received cervical length measurement. Those who were found to have cervical length ≤25 mm were offered 200 mg vaginal progesterone daily along with cervical pessary. The primary outcome was preterm birth at <37 weeks. The risk of primary outcome was quantified by the relative risk with 95% confidence interval, and was based on the intention-to-screen principle.

RESULTS

A total of 1334 asymptomatic women with singleton pregnancies and without prior preterm birth, were included in the trial. Out of the 675 women randomized in the transvaginal ultrasound cervical length screening group, 13 (1.9%) were found to have transvaginal ultrasound cervical length ≤25 mm during the screening. Preterm birth at <37 weeks of gestation occurred in 48 women in the transvaginal ultrasound cervical length screening group (7.5%), and 54 women in the control group (8.7%) (relative risk, 0.86; 95% confidence interval, 0.59-1.25). Women randomized in the transvaginal ultrasound cervical length screening group had no significant differences in the incidence of preterm birth at less than 34, 32, 30, 28, and 24 weeks of gestation.

CONCLUSION

The introduction of a universal transvaginal ultrasound cervical length screening program at 18 0/6 to 23 6/7 weeks of gestation in singleton pregnancies without prior spontaneous preterm birth, with treatment for those with cervical length ≤25 mm, did not result in significant lower incidence of preterm delivery than the incidence without the screening program.

Predicting Spontaneous Labor beyond 39 Weeks among Low-Risk Expectantly Managed Pregnant Patients

OBJECTIVES

The aim of the study was to identify the characteristics associated with spontaneous labor onset in pregnant patients undergoing expectant management at greater than 39 weeks' gestation and delineate perinatal outcomes associated with spontaneous labor compared with labor induction.

STUDY DESIGN

This was a retrospective cohort study of singleton pregnancies at ≥390/7 weeks' gestation delivered at a single center in 2013. The exclusion criteria were elective induction, cesarean delivery or presence of a medical indication for delivery at 39 weeks, more than one prior cesarean delivery, and fetal anomaly or demise. We evaluated prenatally available maternal characteristics as potential predictors of the primary outcome-spontaneous labor onset. Multivariable logistic regression was used to generate two parsimonious models: one with and one without third trimester cervical dilation. We also performed sensitivity analysis by parity and timing of cervical examination, and compared the mode of delivery and other secondary outcomes between patients who went into spontaneous labor and those who did not.

RESULTS

Of 707 eligible patients, 536 (75.8%) attained spontaneous labor and 171 (24.2%) did not. In the first model, maternal body mass index (BMI), parity, and substance use were identified as the most predictive factors. Overall, the model did not predict spontaneous labor (area under the curve [AUC]: 0.65; 95% confidence interval [CI]: 0.61-0.70) with high accuracy. The addition of third trimester cervical dilation in the second model did not significantly improve labor prediction (AUC: 0.66; 95% CI: 0.61-0.70; p = 0.76). These results did not differ by timing of cervical examination or parity. Patients admitted in spontaneous labor had lower odds of cesarean delivery (odds ratio [OR]: 0.33; 95% CI: 0.21-0.53) and neonatal intensive care unit (NICU) admission (OR: 0.38; 95% CI: 0.15-0.94). Other perinatal outcomes were similar between the groups.

CONCLUSION

Maternal characteristics did not predict spontaneous labor onset at ≥39 weeks' gestation with high accuracy. Patients should be counseled on the challenges of labor prediction regardless of parity and cervical examination, outcomes if spontaneous labor does not occur, and benefits of labor induction.

KEY POINTS

· Majority of patients will attain spontaneous labor at ≥39 weeks.. · Maternal characteristics do not predict labor at ≥39 weeks.. · Spontaneous labor has associated lower perinatal risks.. · A shared decision model should be utilized in counseling patients who may choose expectant management..

An evaluation of cervical maturity for Chinese women with labor induction by machine learning and ultrasound images

BACKGROUND

To evaluate the improvement of evaluation accuracy of cervical maturity for Chinese women with labor induction by adding objective ultrasound data and machine learning models to the existing traditional Bishop method.

METHODS

The machine learning model was trained and tested using 101 sets of data from pregnant women who were examined and had their delivery in Peking University Third Hospital in between December 2019 and January 2021. The inputs of the model included cervical length, Bishop score, angle, age, induced labor time, measurement time (MT), measurement time to induced labor time (MTILT), method of induced labor, and primiparity/multiparity. The output of the model is the predicted time from induced labor to labor. Our experiments analyzed the effectiveness of three machine learning models: XGBoost, CatBoost and RF(Random forest). we consider the root-mean-squared error (RMSE) and the mean absolute error (MAE) as the criterion to evaluate the accuracy of the model. Difference was compared using t-test on RMSE between the machine learning model and the traditional Bishop score.

RESULTS

The mean absolute error of the prediction result of Bishop scoring method was 19.45 h, and the RMSE was 24.56 h. The prediction error of machine learning model was lower than the Bishop score method. Among the three machine learning models, the MAE of the model with the best prediction effect was 13.49 h and the RMSE was 16.98 h. After selection of feature the prediction accuracy of the XGBoost and RF was slightly improved. After feature selection and artificially removing the Bishop score, the prediction accuracy of the three models decreased slightly. The best model was XGBoost (p = 0.0017). The p-value of the other two models was < 0.01.

CONCLUSION

In the evaluation of cervical maturity, the results of machine learning method are more objective and significantly accurate compared with the traditional Bishop scoring method. The machine learning method is a better predictor of cervical maturity than the traditional Bishop method.

Prediction of delivery after 40 weeks by antepartum ultrasound in singleton multiparous women: a prospective cohort study

OBJECTIVE

Universal elective induction of labor (IOL) in singleton parous pregnancies has been advocated to reduce the rate of cesarean section (CD), without impacting on maternal outcome. However, about 50% of women deliver after 40 weeks; therefore, an accurate estimation of the time of delivery might avoid unnecessary early IOL. The aim of this study was to test the diagnostic accuracy of ultrasound in predicting delivery ≥40 weeks of gestation in singleton parous women.

METHODS

Prospective cohort study of singleton parous women undergoing a dedicated ultrasound assessment at 36-38 weeks of gestation. The primary outcome was spontaneous vaginal delivery ≥40 weeks of gestation. Cervical length (CL), posterior cervical angle (PCA), sonoelastographic hardness ratio (HR), angle of progression (AoP) and head perineal distance (HPD) were measured. Multivariate logistic regression and area under the curve (AUC) analyses were used to test the diagnostic accuracy of different maternal and ultrasound characteristics in predicting delivery ≥40 weeks.

RESULTS

518 singleton pregnancies were included in the analysis and 235 (45.4%) delivered ≥40 weeks. CL (29 vs 19 mm; p ≤ .0001) and HPD (50 vs 47 mm; p = .001) were longer, HR higher (38.9 vs 35.5; p = .04), while PCA (98° vs 104°; p ≤ .0001) and AOP narrower (93° vs 98°; p = .029) in pregnancies delivered compared to those not delivered after 40 weeks of gestation. At multivariable logistic regression analysis, CL (aOR 1.206; 95% CI 1.164-1.250), HPD (aOR 1.127; 95% CI 1.066-1.191) and HR (aOR 1.022; 95% CI 1.003-1.041 were the only variables independently associated with delivery ≥40 weeks. CL showed had an AUC of 0.863 in predicting delivery ≥40 weeks of gestation, with an optimal cutoff of 23.5 mm. Integration of HPD and HR did not significantly improve the diagnostic performance of CL alone to predict delivery ≥40 weeks (AUC 0.870; p = .472).

CONCLUSION

Cervical length at 36-38 weeks has a good diagnostic accuracy to predict spontaneous vaginal delivery at ≥40 weeks. Universal assessment of CL in the third trimester of pregnancy may help in identifying those women who may benefit of elective IOL at 39 weeks.

Transvaginal two-dimensional ultrasound measurement of cervical volume to predict the outcome of the induction of labour: a prospective observational study

Background

Assessing the likelihood of success of induction of labour using ultrasonically measured cervical volume is an important research question.

Method

A prospective observational study was carried out at North Colombo Teaching Hospital, Ragama, Sri Lanka. Pre-induction digital cervical assessment, transvaginal cervical length, and cervical volume measurements were performed. Inductions with singleton pregnancies at term were included. Basic demographic and clinical details, independent variables (Bishop score, cervical length and cervical volume), and dependent variables (frequency of delivery within 24 h and induction to delivery interval) were recorded. Vaginal delivery within 24 h was the primary outcome.

Results

We studied 100 pregnant women who had induction of labour. Median (IQR) Bishop score was 5 (3–6), mean (SD) cervical length was 3.6 (0.7) cm, and mean (SD) cervical volume was 27.5 (10.4) cm³. Cervical length was the best predictor for predicting the likelihood of vaginal delivery within 24 h [aOR – 12.12 (3.44, 42.71); < 0.001], and cervical volume also appeared to be a significant potential predictor [aOR-1.10 (1.01, 1.17); 0.01]. Cervical length was found to have the highest AUC (0.83) followed by the cervical volume (0.74). The best cut-off value for cervical volume in predicting the likelihood of vaginal delivery within 24 h was less than 28.5 cm³ with a sensitivity of 72% and specificity of 74%.

Conclusions

Transvaginal sonographic measurement of cervical volume appears to be a potential novel predictor for the likelihood of vaginal delivery within 24 h of induction of labour. Cervical length is still more superior to cervical volume in predicting the likelihood of vaginal delivery. Bishop score was not a significant predictor in this context.

Ultrasound assessment of the cervix in predicting successful membrane sweeping: a prospective observational study

OBJECTIVE

Membrane sweeping has been shown to potentially reduce the need for formal induction of labor. The primary aim of this study was to elucidate the role of ultrasound assessment of the cervix in predicting successful membrane sweeping in singleton pregnancies at term; the secondary aim was to build a multiparametric prediction model integrating, maternal, pregnancy and ultrasound characteristics, able to anticipate spontaneous delivery at term.

METHODS

Prospective observational study including singleton pregnancies at term undergoing membrane sweeping. Cervical length (CL) and posterior cervical angle (PCA) were assessed on ultrasound immediately before the procedure. Primary outcome was successful membrane sweeping, defined as spontaneous vaginal birth without formal induction within the 24hours. A subgroup analysis was computed considering women experiencing spontaneous vaginal birth within 48 hours from the procedure. The secondary outcome was to explore the diagnostic performance of a multiparametric model including maternal, pregnancy, and ultrasound assessment of the cervix in predicting spontaneous vaginal birth following membrane sweeping. Multivariate logistic regression and area under the curve (ROC) analyses were used to compute the data.

RESULTS

One hundred fifty-nine singleton pregnancies undergoing membrane sweeping were included in the analysis. Successful membrane sweeping within 24 hours occurred in 68/159 women (36.5%). Parity (aOR = 1.87, 95% confidence interval [CI] 1.2-2.44), gestational age (aOR = 1.32, 95% CI 1.14-1.76), CL (aOR = 0.47, 95%CI 0.31-0.69) and PCA (aOR = 1.22, 95%CI 1.07-1.41) were independently associated with spontaneous vaginal birth within 24 hours from sweeping. The AUC of the constructed model was 0.796 (95% CI 0.727-0.865). Likewise, CL (aOR = 0.80, 95%CI 0.72-0.89), PCA (aOR = 1.19, 95%CI 1.10-1.28) and gestational age at the procedure (aOR = 1.65, 95%CI 1.09-1.86; p = .04) were independently associated with delivery within 48 hours with an AUC of 0.737 (95%CI 0.659-0.815).

CONCLUSIONS

Cervical ultrasound assessment of the cervix prior to membrane sweeping is associated with spontaneous vaginal birth within 24 and 48 hours from the procedure. The combination of cervical ultrasonographic parameters with parity and gestational age can predict the chances of delivery within 24 or 48 hours from membrane sweeping. The findings from this study support the use of ultrasound assessment of the cervix prior to membrane sweeping in order to more accurately predict the likelihood of spontaneous vaginal delivery.

Sonoelastographic Assessment of the Uterine Cervix in the Prediction of Imminent Delivery in Singleton Nulliparous Women Near Term: A Prospective Cohort Study

OBJECTIVES

To explore the role of newly developed software to assess cervical sonoelastography in predicting the onset of spontaneous delivery in singleton pregnancies at term and to compare its diagnostic performance with that provided by the cervical length (CL) and posterior cervical angle (PCA).

METHODS

This work was a prospective study including nulliparous singleton pregnancies at gestational ages of 37 weeks to 38 weeks 6 days. The CL, PCA, hardness ratio (HR), and mean strain from the internal os and external os were obtained by a transvaginal ultrasound approach using semiautomatic software (E-Cervix; Samsung Medison Co, Ltd, Seoul, Korea). Multivariate logistic regression and area under the curve analyses were used to test the strength of the association and the diagnostic performance of the variables considered in predicting delivery within 7 days.

RESULTS

A total of 398 women were included, and 24.6% delivered within 7 days. The CL was shorter (19.5 versus 2 7 mm; P = .0001), PCA narrower (99° versus 102°; P = .02) HR lower (35.3 versus 40.7; P = .0001), mean strain from the external os higher (0.41 versus 0.35; P = .0001), and mean strain from the internal os higher (0.38 versus 0.33; P = .0001) higher in women who delivered within 7 days from the assessment. At the multivariable logistic regression analysis, the CL (adjusted odds ratio, 1.307) and HR (adjusted odds ratio, 1.227) were the only variables independently associated with delivery within 1 week. A model combining the CL and HR showed an area under the curve of 0.873 in predicting delivery within 7 days, higher than that obtained by using the CL and HR singularly (P ≤ .0001).

CONCLUSIONS

The HR assessed by sonoelastography improves the efficacy of the CL in predicting imminent delivery in nulliparous women close to term.

Sonographic measurement of cervical length and head perineum distance before labor to predict time of delivery

OBJECTIVES

This was an observational study on cervical length and head perineum distance and the prediction of time of delivery. One-hundred and twenty-five nulliparous women with uncomplicated, term, singleton pregnancy were recruited when they presented to the labor ward with show or infrequent painful uterine contractions (less than three contractions in ten minutes on a 30 min cardiotocogram). Apart from digital vaginal examination to assess cervical length and dilatation, sonographic cervical length and head perineum distance were measured by two-dimensional ultrasound. We compared women who delivered within 72 h of presentation of labor symptoms, with women who did not. After excluding ten women whose labor was induced and delivered within 72 h of presentation, one hundred and fifteen women were included for final data analysis.

MAIN FINDINGS

Forty-nine women (42.6%) delivered while sixty-six women (57.4%) remained undelivered at 72 h of presentation of symptoms of labor. There was no statistically significant difference between the two groups on age, presence of show, contractions, fetal head station and presentation and mode of delivery. For the group who had delivered within 72 h of presentation of labor symptoms, the mean sonographic cervical length was 1.87 cm ± 0.62 cm, while the head perineum distance was 6.01 cm ± 1.15 cm. For the other group, the mean sonographic cervical length was 2.10 cm ± 0.83 cm; head perineum distance was 6.03 cm ± 1.18 cm. There was no statistically significant difference between the groups for both sonographic cervical length (p = .90); and head perineum distance (p = .08). We also compared the cervical length measured by digital vaginal examination versus sonography. The median sonographic measurements were 1.47 cm, 2.11 cm and 2.79 cm at "1 cm," "2 cm" and "3 cm" digital vaginal measurement, respectively. However, there was extensive overlap between digitally and sonographically measured cervical length. Prediction accuracy of cervical length and head perineum distance was poor. The area under curve (AUC) of receiver operating characteristic (ROC) curve were 0.433 for sonographic cervical length and 0.501 for HPD.

CONCLUSION

Transperineal sonographical assessment of cervical length and head perineum distance before labor was not useful in predicting the time of delivery. However, it can be explored as an alternative assessment method when digital vaginal examination is not preferred.

Role of ante-partum ultrasound in predicting vaginal birth after cesarean section: A prospective cohort study

INTRODUCTION

Vaginal birth after caesarean delivery is associated with better outcomes compared to repeat caesarean section. Accurate antenatal risk stratification of women undergoing a trial of labor after caesarean section is crucial in order to maximize perinatal and maternal outcomes. The primary aim of this study was to explore the role of antepartum ultrasound in predicting the probability of vaginal birth in women attempting trial of labor; the secondary aim was to build a multiparametric prediction model including pregnancy and ultrasound characteristics able to predict vaginal birth and compare its diagnostic performance with previously developed models based exclusively upon clinical and pregnancy characteristics.

METHODS

Prospective study of consecutive singleton pregnancies scheduled for trial of labor undergoing a dedicated antepartum ultrasound assessment at 36-38 weeks of gestation. Head circumference, estimated fetal weight cervical length, sub-pubic angle were recorded before the onset of labour. The obstetricians and midwives attending the delivery suite were blinded to the ultrasound findings. Multivariate logistic regression and area under the curve analyses were used to explore the strength of association and test the diagnostic accuracy of different maternal and ultrasound characteristics in predicting vaginal birth. Comparison with previously reported clinical models developed by the Maternal-Fetal Medicine Unit Network (Grobman's models) was performed using De Long analysis.

RESULTS

A total of 161women who underwent trial of labor were included in the study. Among them 114 (70.8 %) women had successful vaginal birth. At multivariable logistic regression analysis maternal height (adjusted odds ratio (aOR):1.24;9 5% Confidence Interval (CI)1.17-1.33), previous C-section for arrest labor (aOR:0.77; 95 %CI0.66-0.93), cervical dilation at admission (aOR:1.35 ; 95 %CI1.12-1.74), fetal head circumference (aOR:0.77 ; 5%CI0.43-0.89), subpubic angle (aOR:1.39 95 %CI1.11-1.99) and cervical length (aOR:0.82 95 % CI0.54-0.98) were independently associated with VBAC. A model integrating these variables had an area under curve of 0.839(95 % CI 0.710-0.727) for the prediction of vaginal birth, significantly higher than those achieved with intake (0.694; 95 %CI0.549-0.815; p = 0.01) and admission (0.732: 95 % CI 0.590-0.84; p = 0.04) models reported by Grobman.

CONCLUSION

Antepartum prediction of vaginal birth after a caesarean section is feasible. Fetal head circumference, subpubic angle and cervical length are independently associated and predictive of vaginal birth. Adding these variables to a multiparametric model including maternal parameters improves the diagnostic accuracy of vaginal birth compared to those based only on maternal characteristic.

Prediction of delivery after 40 weeks by antepartum ultrasound in singleton nulliparous women: a prospective cohort study

BACKGROUND

Induction of labor at 39 weeks of gestation is associated with better maternal and perinatal outcomes than expectant management. However, a policy of induction of labor implies the identification of women who will deliver after 40 weeks, who are at higher risk of adverse outcome.

OBJECTIVE

This study primarily aimed to elucidate the role of antepartum ultrasound in predicting the onset of spontaneous labor in a cohort of low-risk singleton pregnancies, and secondarily to compare its diagnostic performance with that of other ultrasonographic and clinical parameters.

STUDY DESIGN

This was a prospective study including singleton nulliparous women undergoing a dedicated ultrasound assessment at 36 to 38 weeks of gestation. The primary outcome was delivery ≥40 weeks of gestation. The ultrasound parameters explored were cervical length, posterior cervical angle, angle of progression, and head-perineum distance. Multivariate logistic regression, Kaplan-Meier, and area under the curve analyses were used to test the strength of association and diagnostic performance of variables considered in predicting delivery ≥40 weeks.

RESULTS

A total of 457 women were included, and 49.2% delivered ≥40 weeks. Cervical length was longer (30 vs 19 mm; P≤.0001) and posterior cervical angle wider (105° vs 98°, P≤.0001) in women delivering ≥40 weeks than those delivering <40 weeks. Similarly, head-perineum distance was longer (48 vs 40 mm; P=.001) and angle of progression narrower (93° vs 95°; P=.04) in pregnancies delivering after 40 weeks. Conversely, there was no difference in the modified Bishop score between the 2 study groups (P=.689). In multivariable logistic regression analysis, cervical length (adjusted odds ratio, 1.307) and head-perineum distance (adjusted odds ratio, 1.227) were independently associated with delivery ≥40 weeks. Cervical length showed an area under the curve of 0.896 in predicting a delivery after 40 weeks. Integration of head-perineum distance in the diagnostic algorithm did not increase the performance of the model. A cervical length of 24 mm at 36 to 37 weeks of gestation showed the best combination of sensitivity and specificity in predicting delivery ≥40 weeks, with a shorter latency between ultrasound assessment and birth.

CONCLUSION

Antepartum ultrasound can reliably identify a subset of nulliparous women at higher risk of delivering beyond 40 weeks. A cervical length >24 mm at 36 to 37 weeks of gestation shows the optimal combination of sensitivity and specificity in predicting delivery ≥40 weeks. The findings from this study can help in identifying those women for whom elective induction of labor at 39 weeks of gestation would be beneficial in reducing the risk of adverse pregnancy outcome.

Cervical elastography using E-cervix for prediction of preterm birth in singleton pregnancies with threatened preterm labor

Objective: E-Cervix™ (WS80A; Samsung, Seoul, Korea) elastography is a recent quantification tool to measure the stiffness of the cervix using strain elastography. The aim of this study was to evaluate the prediction performance of E-cervix for preterm birth in singleton gestation with threatened preterm labor (PTL).Methods: This was a cohort study of singleton pregnancies without prior preterm birth presenting to obstetrics triage for threatened PTL between 23 0/7 and 33 6/7 week who received screening for PTL with transvaginal ultrasound cervical length (TVU CL) and cervical elastography with E-cervix at the time of triage. Cervical elastography parameters were examined and compared between women who delivered preterm and those who did not. The quantification of cervical strain was calculated by a data analysis system that directly analyses raw data from the region of interest (ROI) and described as hardness ratio (HR), mean strain level within 1 cm from internal os (IOS) and external os (EOS).Results: Ninety-five singleton pregnancies without prior preterm birth and with threatened PTL between 23 0/7 and 33 6/7 week of gestation were included in the study. Forty-two (44.2%) had cervical length <25 mm, and were admitted for true PLT. Out of the 53 women with cervical length ≥25 mm, 40 (75.5%) were discharged, and 13 (24.5%) were admitted. Women with threatened PTL but without true PTL, had significantly higher HR compared to those with true PTL (49.0 ± 20.9% versus 34.8 ± 19.6%; p < .01), and significantly lower stiffness of cervical IOS and EOS. Women who delivered preterm had significantly lower HR compared to those who did not delivery preterm, in overall cohort, and in the subset of only women with true PTL. Incidences of HR < 50% and <35% were statistically significantly higher in women who delivered preterm compared to those who did not (p < .01).Conclusions: Cervical elastography with E-cervix may be useful for the assessment of women presenting to obstetrics triage for threatened PTL. Women with low HR, especially with HR less than 50 or 35%, are at increased risk of PTB.Condensation: Women who delivered preterm had significantly lower HR compared to those who did not delivery preterm and significantly lower IOS and EOS, in overall cohort, and in the subset of women with true PTL. Incidences of HR < 50% and <35% were statistically significantly higher in women who delivered preterm compared to those who did not (p < .01).Key message: Cervical elastography with E-cervix may be useful for the assessment of women presenting to obstetrics triage for threatened PTL.

Evidence-based labor management: before labor (Part 1)

In preparation for labor and delivery, there is high-quality evidence for providers to recommend perineal massage with oil for 5-10 minutes daily starting at 34 weeks until labor; ≥1 daily sets of repeated voluntary contractions of the pelvic floor muscles, performed at least several days of the week starting at approximately 30-32 weeks gestation; no x-ray pelvimetry; sweeping of membranes weekly starting at 37-38 weeks gestation; for women with a risk factor for abnormal outcome plans should be made to deliver in a hospital setting; for low-risk women, alongside birth center birth is associated with maternal benefits and higher satisfaction, compared with hospital birth; midwife-led care for low-risk women; continuous support by a professional such as doula, midwife, or nurse during labor; and training of birth attendants in low- and middle-income countries.

Can the Progression Angle before Labor Help to Predict Cesarean Section?

OBJECTIVE

The aim of this study was to predict cesarean section on a single visit at term using a combination of maternal history and ultrasound markers, including some new markers such as the progression angle used to assess intrapartum progress.

STUDY DESIGN

This was an observational prospective cohort study of singleton term pregnancies that included 575 women. The maternal history and ultrasound markers were obtained on a single visit at 37-38 weeks' gestation. Multivariable logistic regression was used for prediction of cesarean section.

RESULTS

Five hundred and seventy-five women were examined at a median gestational age of 38.3 weeks (range: 35.6-41.6) and a cesarean section was performed on 104 women (18%) - 24 for a fetal indication and 80 for a maternal indication. The risk of cesarean section increased with a previous cesarean section, assisted reproduction techniques, a higher estimated fetal weight, and a greater cervical length, and decreased with a greater maternal height, multiparity, and a wider progression angle. The detection rate for a 20% false positive rate was 69.9% for all cesarean sections, 54.2% for those with a fetal indication, and 77.2% for those with a maternal indication.

CONCLUSIONS

Assessment at 37-38 weeks' gestation of ultrasound markers such as the cervical length, progression angle, and estimated fetal weight, in combination with the maternal history, can predict a cesarean section in labor. Cesarean section for a maternal indication is better predicted than cesarean section for a fetal indication.

Labour and delivery: a clinician's perspective on a biomechanics problem

Predicting how and when a pregnant woman will deliver her fetus has always been a problem for the clinician, and, consequently, there has been little progress made in preventing poor outcomes from pregnancies that deliver too soon or too late. In the opinion of the author, a maternal-fetal medicine specialist, rethinking labour within a biomechanical framework and studying it like an engineering problem could be a promising approach to unlocking the mysteries of labour.

Fetal adrenal gland size and the ability to predict spontaneous term labor

OBJECTIVE

The objective of this study was to evaluate whether ultrasound measured fetal adrenal gland size can be a predictor of spontaneous term labor.

STUDY DESIGN

This study was a diagnostic test accuracy study using a prospective cohort design evaluating the ability of 2-dimensional ultrasound measurement of fetal adrenal gland total length, total width, fetal zone length and fetal zone width in women in the third trimester to predict the primary outcome of spontaneous term labor. Secondary outcomes were vaginal delivery, length of labor, and maternal and neonatal morbidities.

RESULTS

Of 43 patients recruited, 3 were excluded. 11 (25.6%) presented in spontaneous labor and 29 (67.4%) underwent induction of labor. Patient demographics were similar for all included except for admission cervical exam and oxytocin use. A receiver operative curve was created to assess test predictability. Weighted width of fetal adrenal gland was the best predictor of spontaneous labor amongst variables measured with an area under the curve of 0.674, p = 0.93. w/W ≥ 0.41 had a sensitivity of 91.0%, specificity of 44.8%, positive predictive value of 38.5% and a negative predictive value of 92.3%. Maternal and neonatal morbidities were not different between the spontaneous labor group and the induction of labor group.

CONCLUSION

Ultrasound measured fetal w/W was moderately predictive of spontaneous labor.

Preterm birth: seven-year retrospective study in a single centre population

BACKGROUND

Preterm birth is a health and social problem, considered the leading cause of neonatal mortality worldwide. It is associated with higher rates of neurodevelopmental morbidity, sensorineural impairments and other complications. The aim of the study was to describe the incidence and the major risk factors associated with preterm birth.

METHODS

We performed a single center, observational and retrospective Cohort study in the Division of Obstetrics and Gynaecology, University Hospital "G. Martino", Messina. Clinical records of all pregnant women who delivered from 1st January 2010 to 31 of December 2016 were collected.

RESULTS

In the 7 years considered, a total of 7954 pregnant women were included in our study. The majority of all preterm births were due to infants born late preterm (71.83%), 26.45% were due to preterm and 1.72% to extremely preterm. The preterm cohort had a higher proportion of history of preterm delivery (p < 0.0001), and unmarried (p = 0.003) and underweight or obese patients (p < 0.0001). In addition, prematurity was associated with presence of uterine anomalies (p < 0.0001), vaginal/urinary infections (p = 0.02), poli/oligohydramnios (p < 0.0001), maternal diabetes (p = 0.004), hypertension (p < 0.0001), short cervical length (p < 0.0001).

CONCLUSIONS

We suggest prompt identification of all risk factors associated with preterm birth to apply immediate and appropriate specific interventions.

Quantitative Ultrasound Biomarkers Based on Backscattered Acoustic Power: Potential for Quantifying Remodeling of the Human Cervix during Pregnancy

As pregnancy progresses, the cervix remodels from a rigid structure to one pliable enough to allow delivery of a fetus, a process that involves progressive disorganization of cervical microstructure. Quantitative ultrasound biomarkers that may detect this process include those derived from the backscattered echo signal, namely, acoustic attenuation and backscattered power loss. We recently reported that attenuation and backscattered power loss are affected by tissue anisotropy and heterogeneity in the ex vivo cervix. In this study, we compared attenuation and backscattered power difference in a group of women in early pregnancy (first trimester) with those in a group in late pregnancy (third trimester). We observed a significant decrease in the backscattered power difference in late as compared with early pregnancy, suggesting decreased microstructural organization in late pregnancy, a finding that is consistent with animal models of cervical remodeling. In contrast, we found no difference in attenuation between the time points. These results suggest that the backscattered power difference, but perhaps not attenuation, may be a useful clinical biomarker of cervical remodeling.

Effects of exercise during pregnancy in women with short cervix: Secondary analysis from the Italian Pessary Trial in singletons

OBJECTIVE

To evaluate effects of exercise during pregnancy in asymptomatic singleton pregnancies without prior spontaneous preterm birth (SPTB) but with short transvaginal ultrasound cervical length (TVU CL).

STUDY DESIGN

This is a secondary analysis of the Italian Pessary Trial for the Italian Preterm Birth Prevention (IPP) Working Group. In the original prospective randomized controlled trial asymptomatic singleton pregnancies without prior SPTB but with TVU CL ≤ 25 mm at 18 0/6-23 6/7 weeks were randomized into 1:1 ratio to either cervical pessary or no pessary. During their follow-up visits, women were asked about their activity. For the purpose of this secondary analysis, women were classified in the following groups, using the information obtained in the follow-up visit one month after randomization: 1) Exercise group, defined as women performing exercise ≥2 days a week for ≥20 min each day. 2) No exercise group, defined as women performing exercise <2 days a week for ≥20 min each day. The primary outcome of this secondary analysis was PTB < 37 weeks.

RESULTS

300 women were included in this analysis. 99 (33.0%) were included in the exercise group. 201 (67.0%) were included in the no exercise group. Of the 201 women in the no exercise group, 90 (44.8%) affirmed that they had reduced their activity after the diagnosis of short cervix despite the research staff recommendations, while the other 111 (55.2%) women performed a sedentary life style even before the diagnosis of short cervix. PTB < 37 weeks occurred in 22 women (22.2%) in the exercise group, and 66 women (32.8%) in the no exercise group (aOR 0.65, 95% CI 0.33-1.03).

CONCLUSION

In asymptomatic singleton pregnancies with short cervix, performing exercise ≥2 days a week for ≥20 min each day does not increase the risk of PTB but is indeed associated with a non-significant reduction in PTB < 37 weeks by 32%.

Midtrimester transvaginal ultrasound cervical length screening for spontaneous preterm birth in diamniotic twin pregnancies according to chorionicity

OBJECTIVE

To compare the mean transvaginal ultrasound (TVU) cervical length (CL) at midtrimester screening for spontaneous preterm birth in asymptomatic monochorionic diamniotic versus dichorionic diamniotic twin pregnancies STUDY DESIGN: This was a multicenter retrospective cohort study. Study subjects were identified at the time of a routine second trimester fetal ultrasound exam at 18 0/7-23 6/7 weeks gestation. We excluded women that received progesterone, pessary, or cerclage. Distribution of CL was determined and normality was examined. Mean of TVU CL were compared between monochorionic diamniotic and dichorionic diamniotic pregnancies. The relationship of TVU CL with gestational age (GA) at delivery and incidence of spontaneous preterm birth (SPTB) at different TVU CL cut offs were assessed. Incidence of short TVU CL, defined as TVU CL ≤30 mm, was also calculated in the two groups.

RESULTS

580 women with diamniotic twin pregnancies underwent TVU CL screening between 18 0/6 and 23 6/7 weeks. 175 (30.2%) were monochorionic diamniotic pregnancies, and 405 (69.8%) were dichorionic pregnancies. The demographic characteristics were similar on both groups. The mean GA at TVU CL was about 20 week in both groups. The mean TVU CL was significantly lower in the monochorionic diamniotic (32.8 ± 10.1) compared to the dichorionic (34.9 ± 8.6) group (MD -2.10 mm, 95% CI -3.91 to -0.29). TVU CL ≤30 mm was 16.6% (29/175) in the monochorionic group, and 11.9% (48/405) in the dichorionic group (aOR 1.48, 95% CI 1.03-2.43). Twins with a monochorionic diamniotic pregnancy had a significantly higher incidence of SPTB (53.1% vs 44.9%; aOR 1.22, 95% CI 1.22-1.79). For any given CL measured between 18 0-7 and 23 6/7 weeks, gestational age at delivery for monochorionic diamniotic pregnancies was about 2 weeks earlier compared to dichorionic pregnancies (MD -2.1 weeks; ANCOVA P < 0.001).

CONCLUSION

Monochorionic diamniotic twin pregnancies had a higher rate of spontaneous preterm birth than dichorionic diamniotic pregnancies. The higher rate of spontaneous preterm delivery in monochorionic pregnancies is associated with lower midtrimester TVU CL when compared to dichorionic pregnancies.

Effect of Cervical Pessary on Spontaneous Preterm Birth in Women With Singleton Pregnancies and Short Cervical Length: A Randomized Clinical Trial

IMPORTANCE

Spontaneous preterm birth is a major cause of perinatal morbidity and mortality. It is unclear if a cervical pessary can reduce the risk of spontaneous preterm delivery.

OBJECTIVE

To test whether in asymptomatic women with singleton pregnancies and no prior spontaneous preterm birth but with short cervical length on transvaginal ultrasound, use of a cervical pessary would reduce the rate of spontaneous preterm birth at less than 34 weeks of gestation.

DESIGN, SETTING, AND PARTICIPANTS

Parallel-group, nonblinded, randomized clinical trial conducted from March 1, 2016, to May 25, 2017, at a single center in Italy. Asymptomatic women with singleton gestations, no previous spontaneous preterm births, and cervical lengths of 25 mm or less at 18 weeks 0 days to 23 weeks 6 days of gestation were eligible.

INTERVENTIONS

Patients were randomized 1:1 to receive either cervical pessary (n = 150) or no pessary (n = 150). The pessary was removed between 37 weeks 0 days and 37 weeks 6 days of gestation or earlier if clinically indicated. The control group received standard care. For cervical length of 20 mm or shorter, women in both groups were prescribed vaginal progesterone, 200 mg/d, until 36 weeks 6 days of gestation. No bed rest or activity restriction was recommended.

MAIN OUTCOMES AND MEASURES

The primary end point was spontaneous preterm birth at less than 34 weeks of gestation. Secondary outcomes were adverse events.

RESULTS

Among 300 women who were randomized (mean age, 29 [SD, 6.3] years; mean gestational age, 22 [SD, 1.3] weeks), 100% completed the trial. The primary end point occurred in 11 women (7.3%) in the pessary group and 23 women (15.3%) in the control group (between-group difference, -8.0% [95% CI, -15.7% to -0.4]; relative risk, 0.48 [95% CI, 0.24-0.95]). During follow-up, the pessary group had a higher rate of increased or new vaginal discharge (86.7% vs 46.0%; between-group difference, +40.7% [95% CI, +30.1%-+50.3%]; relative risk, 1.88 [95% CI, 1.57-2.27]).

CONCLUSIONS AND RELEVANCE

Among women without prior spontaneous preterm birth who had asymptomatic singleton pregnancies and short transvaginal cervical length, use of a cervical pessary, compared with no pessary use, resulted in a lower rate of spontaneous preterm birth at less than 34 weeks of gestation. The results of this single-center, nonblinded study among selected pregnant women require confirmation in multicenter clinical trials.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT02716909.

Cerclage for sonographic short cervix in singleton gestations without prior spontaneous preterm birth: systematic review and meta-analysis of randomized controlled trials using individual patient-level data

OBJECTIVE

The aim of this systematic review and meta-analysis was to quantify the efficacy of cervical cerclage in preventing preterm birth (PTB) in asymptomatic singleton pregnancies with a short mid-trimester cervical length (CL) on transvaginal sonography (TVS) and without prior spontaneous PTB.

METHODS

Electronic databases were searched from inception of each database until February 2017. No language restrictions were applied. All randomized controlled trials (RCTs) of asymptomatic singleton pregnancies without prior spontaneous PTB, found to have short CL < 25 mm on mid-trimester TVS and then randomized to management with either cerclage or no cerclage, were included. Corresponding authors of all the included trials were contacted to obtain access to the data and perform a meta-analysis of individual patient-level data. Data provided by the investigators were merged into a master database constructed specifically for the review. Primary outcome was PTB < 35 weeks. Summary measures were reported as relative risk (RR) with 95% CI. The quality of the evidence was assessed using the GRADE approach.

RESULTS

Five RCTs, including 419 asymptomatic singleton gestations with TVS-CL < 25 mm and without prior spontaneous PTB, were analyzed. In women who were randomized to the cerclage group compared with those in the control group, no statistically significant differences were found in PTB < 35 (21.9% vs 27.7%; RR, 0.88 (95% CI 0.63-1.23); I²  = 0%; five studies, 419 participants), < 34, < 32, < 28 and < 24 weeks, gestational age at delivery, preterm prelabor rupture of membranes (PPROM) and neonatal outcomes. In women who received cerclage compared with those who did not, planned subgroup analyses revealed a significantly lower rate of PTB < 35 weeks in women with TVS-CL < 10 mm (39.5% vs 58.0%; RR, 0.68 (95% CI, 0.47-0.98); I²  = 0%; five studies; 126 participants) and in women who received tocolytics (17.5% vs 32.7%; RR, 0.54 (95% CI, 0.31-0.93); I²  = 0%; four studies; 169 participants) or antibiotics (18.3% vs 31.5%; RR, 0.58 (95% CI, 0.33-0.98); I²  = 0%; three studies; 163 participants) as additional therapy to cerclage. The quality of evidence was downgraded two levels because of serious imprecision and indirectness, and therefore was judged as low.

CONCLUSIONS

In singleton gestations without prior spontaneous PTB but with TVS-CL < 25 mm in the second trimester, cerclage does not seem to prevent preterm delivery or improve neonatal outcome. However, in these pregnancies, cerclage seems to be efficacious at lower CLs, such as < 10 mm, and when tocolytics or antibiotics are used as additional therapy, requiring further studies in these subgroups. Given the low quality of evidence, further well-designed RCTs are needed to confirm the findings of this study. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Risk of spontaneous preterm birth in IVF-conceived twin pregnancies

OBJECTIVE

To compare the mean transvaginal ultrasound (TVU) cervical length (CL) at midtrimester in screening for preterm birth in in vitro (IVF)-conceived twin pregnancies versus spontaneously-conceived twin pregnancies.

METHODS

This was a retrospective cohort study. Potential study subjects were identified at the time of a routine second trimester fetal ultrasound exam at 18 0/7 to 23 6/7-week gestation. All women with twin diamniotic pregnancies screened with a single TVU CL for this trial were included. Mean TVU CLs were compared between IVF-conceived twin pregnancies and spontaneously-conceived twin pregnancies. The relationship of TVU CL with gestational age at delivery was assessed. Incidence of short TVU CL, defined as TVU CL ≤30 mm, was also calculated in the two groups. The primary outcome was the mean of TVU CL. Distribution of CL was determined and normality was examined in both groups Results: A total of 668 women with diamniotic twin pregnancies who underwent TVU CL screening between 18 0/6 and 23 6/7 weeks were included. 158 (23.7%) were IVF-conceived pregnancies, and 510 (76.3%) were spontaneously-conceived pregnancies. No women received progesterone, pessary, or cerclage for preterm birth prevention during pregnancy. The mean TVU CL was significantly lower in the IVF-conceived group (32.2 ± 10.5 mm) compared to the spontaneously-conceived group (34.1 ± 9.1 mm) (mean difference (MD) - 1.90 mm, 95%CI -3.72 to -0.08). The incidence of TVU CL ≤30 mm was 30.4% in the IVF-conceived group and 21.6% in the spontaneously-conceived group (adjusted odds ratio (aOR) 1.59, 95%CI 1.06-2.37). IVF-conceived twins had a significantly higher risk of spontaneous preterm birth <34 weeks (32.9 versus 21.2%; aOR 1.83, 95% confidence interval (CI) 1.23-2.71) and higher rate of delivery due to spontaneous onset of labor (64.5 versus 54.9%; aOR 1.50, 95%CI 1.03-2.17). For any given TVU CL measured between 18 0-7 and 23 6/7 weeks, gestational age at delivery for IVF-conceived twins was earlier by about 1 week on average compared with spontaneously-conceived twins.

CONCLUSIONS

The higher rate of spontaneous preterm birth in IVF-conceived twin pregnancies is predicted by lower midtrimester TVU CL, as well as by the lower gestational age at birth per any given CL in the IVF-conceived compared to the spontaneously-conceived twin pregnancies.

Interventions for treating hyperemesis gravidarum: a Cochrane systematic review and meta-analysis

INTRODUCTION

While nausea and vomiting in early pregnancy are very common, affecting approximately 80% of the pregnancies, hyperemesis gravidarum is a severe form affecting 0.3-1.0% of the pregnancies. Although hyperemesis gravidarum is rarely a source of mortality, it is a significant source of morbidity. It is one of the most common indications for hospitalization in pregnancy. Beyond the maternal and fetal consequences of malnutrition, the severity of hyperemesis symptoms causes a major psychosocial burden leading to depression, anxiety, and even pregnancy termination. The aim of this meta-analysis was to examine all randomized controlled trials of interventions specifically for hyperemesis gravidarum and evaluate them based on both subjective and objective measures of efficacy, maternal and fetal/neonatal safety, and economic costs.

MATERIAL AND METHODS

Randomized controlled trials were identified by searching electronic databases. We included all randomized controlled trials for the treatment of hyperemesis gravidarum. The primary outcome was intervention efficacy as defined by severity, reduction, or cessation in nausea/vomiting; number of episodes of emesis; and days of hospital admission. Secondary outcomes included other measures of intervention efficacy, adverse maternal/fetal/neonatal outcomes, quality of life measures, and economic costs.

RESULTS

Twenty-five trials (2052 women) met the inclusion criteria but the majority of 18 different comparisons described in the review include data from single studies with small numbers of participants. Selected comparisons reported below: No primary outcome data were available when acupuncture was compared with placebo. There was insufficient evidence to identify clear differences between acupuncture and metoclopramide in a study with 81 participants regarding reduction/cessation in nausea or vomiting (risk ratio (RR) 1.40, 95% CI 0.79-2.49 and RR 1.51, 95% CI 0.92-2.48, respectively). Midwife-led outpatient care was associated with fewer hours of hospital admission than routine inpatient admission (mean difference (MD) - 33.20, 95% CI -46.91 to -19.49) with no difference in pregnancy-unique quantification of emesis and nausea (PUQE) score, decision to terminate the pregnancy, miscarriage, small-for-gestational age infants, or time off work when compared with routine care. Women taking vitamin B6 had a slightly longer hospital stay compared with placebo (MD 0.80 days, 95% CI 0.08-1.52). There was insufficient evidence to demonstrate a difference in other outcomes including mean number of episodes of emesis (MD 0.50, 95% CI -0.40-1.40) or side effects. A comparison between metoclopramide and ondansetron identified no clear difference in the severity of nausea or vomiting (MD 1.70, 95% CI -0.15-3.55, and MD -0.10, 95% CI -1.63-1.43; one study, 83 women, respectively). However, more women taking metoclopramide complained of drowsiness and dry mouth (RR 2.40, 95% CI 1.23-4.69, and RR 2.38, 95% CI 1.10-5.11, respectively). There were no clear differences between groups for other side effects. In a single study with 146 participants comparing metoclopramide with promethazine, more women taking promethazine reported drowsiness, dizziness, and dystonia (risk ratio (RR) 0.70, 95% CI 0.56-0.87, RR 0.48, 95% CI 0.34-0.69, and RR 0.31, 95% CI 0.11-0.90, respectively). There were no clear differences between groups for other important outcomes including quality of life and other side effects. In a single trial with 30 women, those receiving ondansetron had no difference in duration of hospital admission compared to those receiving promethazine (mean difference (MD) 0.00, 95% CI -1.39-1.39), although there was increased sedation with promethazine (RR 0.06, 95% CI 0.00-0.94). Regarding corticosteroids, in a study with 110 participants there was no difference in days of hospital admission compared to placebo (MD -0.30, 95% CI -0.70-0.10), but there was a decreased readmission rate (RR 0.69, 95% CI 0.50-0.94; 4 studies, 269 women). For hydrocortisone compared with metoclopramide, no data were available for primary outcomes and there was no difference in the readmission rate (RR 0.08, 95% CI 0.00-1.28; one study, 40 women). In a study with 80 women, compared to promethazine, those receiving prednisolone had increased nausea at 48 h (RR 2.00, 95% CI 1.08-3.72), but not at 17 days (RR 0.81, 95% CI 0.58-1.15). There was no clear difference in the number of episodes of emesis or subjective improvement in nausea/vomiting.

CONCLUSIONS

While there were a wide range of interventions studied, both pharmaceutical and otherwise, there were a limited number of placebo controlled trials. In comparing the efficacy of the commonly used antiemetics, metoclopramide, ondansetron, and promethazine, the results of this review do not support the clear superiority of one over the other in symptomatic relief. Other factors such as side effect profile medication safety and healthcare costs should also be considered when selecting an intervention.

Cervical Evaluation: From Ancient Medicine to Precision Medicine

Since ancient times, cervical assessment for predicting timing of delivery has relied primarily on digital (subjective) assessment of dilatation, softening, and length. To date, transvaginal ultrasound cervical length is the only one of these parameters that meets criteria for a biomarker; no objective, quantitative measure of cervical dilatation or softening has gained clinical acceptance. This review discusses how the cervix has been assessed from ancient times to the present day and how a precision medicine approach could improve understanding of not only the cervix, but also parturition in general.