Sonographic longitudinal cervical length measurements in nulliparous women at term: prediction of spontaneous onset of labor

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.

Prediction of spontaneous onset of labor at term (PREDICT study): Research protocol

Background

Recent studies have shown that elective induction of labor versus expectant management after 39 weeks of pregnancy result in lower incidence of perinatal complications, while the proportion of cesarean deliveries remains stable, or even decreases. Still, evidence regarding collateral consequences of the potential increase of induction of labor procedures is still lacking. Also, the results of these studies must be carefully interpreted and thoroughly counter-balanced with women’s thoughts and opinions regarding the active management of the last weeks of pregnancy. Therefore, it may be useful to develop a tool that aids in the decision-making process by differentiating women who will spontaneously go into labor from those who will require induction.

Objective

To develop a predictive model to calculate the probability of spontaneous onset of labor at term.

Methods

We designed a prospective national multicentric observational study including women enrolled at 39 weeks of gestation, carrying singleton pregnancies. After signing an informed consent form, several clinical, ultrasonographic, biophysical and biochemical variables will be collected by trained staff. If delivery has not occurred at 40 weeks of pregnancy, a second visit and evaluation will be performed. Prenatal care will be continued according to current hospital guidelines. Once recruitment is completed, the information gathered will be used to develop a logistic regression-based predictive model of spontaneous onset of labor between 39 and 41 weeks of gestation. A secondary exploration of the data collected at 40 weeks, as well as a survival analysis regarding time-to-delivery outcomes will also be performed. A total sample of 429 participants is needed for the expected number of events.

Conclusion

This study aims to develop a model which may help in the decision-making process during follow-up of the last weeks of pregnancy.

Trial registration

NCT05109247 (clinicaltrials.gov).

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.

The value of measuring cervical length between 24 and 28 weeks of gestation for predicting the risk of late and post-term pregnancy

OBJECTIVE

The aim of this study was to investigate the value of measuring cervical length (CL) between 24 and 28 weeks of gestation for predicting the risk of late and post-term pregnancy.

METHODS

In this prospective longitudinal study, pregnant women whose CL was measured between 24 and 28 weeks were followed until delivery. The CL was adjusted for confounders and the results are presented using odds ratio and receiver operating characteristic curve (ROC).

RESULTS

A total of 874 women met the inclusion criteria. The median value of CL measured between 24 and 28 weeks was 34.0 mm (30.0-38.0 25%, 75% interquartile range). The risk of late and post-term pregnancy was 5.8 times higher in pregnant women with a CL above 35 mm between the 24 and 28 weeks of gestation (95% CI: 2.65-12.94 adjusted OR = 5.8, p < .001). For pregnancies exceeding the 38th week, it was observed that the duration of the gestation increases as CL values increase.

CONCLUSIONS

In this study, it has been demonstrated that measuring the CL between 24 and 28 weeks of gestation can predict late and post-term pregnancy. Prolonged pregnancy may cause neonatal and fetal complications and anxiety. CL measurement performed in these weeks can help prepare pregnant women for a possible prolonged pregnancy and cope with prolonged pregnancy anxiety.

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.

Predictive factors of labour onset using ultrasonography

We analysed the effectiveness of transvaginal ultrasonographic and foetal/maternal pulse Doppler findings as predictors of labour onset within 1 week. We included 22 single normal pregnancies and evaluated the one-point and short- and long-term differences in uterine artery pulsatility index (PI), umbilical artery PI, middle cerebral artery PI (MCA-PI), peak systolic velocity, and cervical length (CL). Presence of funnelling and membrane separation over the internal cervical os was evaluated. Significant changes were observed in the one-point measurement of and short-term and long-term differences in CL, the one-point measurement of and long-term difference in MCA-PI, and the presence of membrane separation (Grade 2). In multivariate analysis, the significant predictors were short-term differences in CL (odds ratio [OR]: 5.27), long-term differences in MCA-PI (OR: 13.3), and presence of membrane separation (Grade 2) (OR: 5.38). Transvaginal ultrasonographic and foetal pulse Doppler findings were effective predictors of labour onset within 1 week.Impact statementWhat is already known on this subject? Parameters reported to predict labour onset include the Bishop score, cervical length, decreased long-term cervical length, funnelling of the internal cervical os, and adrenal gland volume.What do the results of this study add? Short-term changes in cervical length, long-term changes in middle cerebral artery pulsatility index, and the presence of membrane separation Grade 2 were found to be useful predictive factors of labour onset in this study.What are the implications of these findings for clinical practice and/or further research? The prediction of labour onset enables clinicians to properly manage pregnancy and delivery considering maternal and foetal conditions.

Cervical length measurement in nulliparous women at term by ultrasound & its relationship to spontaneous onset of labour

Background & objectives:

Data on serial cervical length (CL) measurements in pregnancy at term to predict spontaneous labour onset are scarce and conflicting. This study was conducted to observe CL changes preceding spontaneous onset of labour, by serial transvaginal sonography (TVS) and transabdominal sonography (TAS), in nulliparous Indian women near term.

Methods:

Only nulliparous women with a singleton foetus in cephalic presentation and who confirmed their gestational age were recruited. Sonographic CL measurements were taken at weekly intervals from 36 wk gestation onwards by a single ultrasonologist. Transabdominal and transvaginal measurements were undertaken using the suitable transducer probes with the women in the supine position.

Results:

A total of 104 women with spontaneous onset of labour were evaluated. There was substantial variation in CL measurements, both by TVS and by TAS, from 36 to 40 wk gestation, although the two sets of measurements correlated closely. Mean CL changed significantly over the last three weeks before delivery. However, only one-third of the women showed CL change of >5 mm per week in the last three weeks. There was poor correlation between gestational age at delivery and the last measured CL, either by TVS or TAS. Length >3.1 mm, measured by TVS at 38 wk gestation, predicted post-dated pregnancy to a limited extent.

Interpretation & conclusions:

Inter-individual variations in CL and in CL changes were large. Thus, it was not practical to predict spontaneous onset of labour by sonographic CL measurement near term. Post-dated pregnancy may be predicted with limited success. Further studies should explore other parameters, in addition to CL.

Serial Change in Cervical Length for the Prediction of Emergency Cesarean Section in Placenta Previa

Purpose

To evaluate whether serial change in cervical length (CL) over time can be a predictor for emergency cesarean section (CS) in patients with placenta previa.

Methods

This was a retrospective cohort study of patients with placenta previa between January 2010 and November 2014. All women were offered serial measurement of CL by transvaginal ultrasound at 19 to 23 weeks (CL1), 24 to 28 weeks (CL2), 29 to 31 weeks (CL3), and 32 to 34 weeks (CL4). We compared clinical characteristics, serial change in CL, and outcomes between the emergency CS group (case group) and elective CS group (control group). The predictive value of change in CL for emergency CS was evaluated.

Results

A total of 93 women were evaluated; 31 had emergency CS due to massive vaginal bleeding. CL tended to decrease with advancing gestational age in each group. Until 29–31 weeks, CL showed no significant differences between the two groups, but after that, CL in the emergency CS group decreased abruptly, even though CL in the elective CS group continued to gradually decrease. On multivariate analysis to determine risk factors, only admissions for bleeding (odds ratio, 34.710; 95% CI, 5.239–229.973) and change in CL (odds ratio, 3.522; 95% CI, 1.210–10.253) were significantly associated with emergency CS. Analysis of the receiver operating characteristic curve showed that change in CL could be the predictor of emergency CS (area under the curve 0.734, p < 0.001), with optimal cutoff for predicting emergency cesarean delivery of 6.0 mm.

Conclusions

Previous admission for vaginal bleeding and change in CL are independent predictors of emergency CS in placenta previa. Women with change in CL more than 6 mm between the second and third trimester are at high risk of emergency CS in placenta previa. Single measurements of short CL at the second or third trimester do not seem to predict emergency CS.

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

BACKGROUND

The possibility to predict the delivery date is a question frequently raised by pregnant women. However, a clinician has currently little to predict when a woman at term will deliver.

OBJECTIVE

To evaluate the predictive accuracy of transvaginal ultrasound (TVU) cervical length (CL) for spontaneous onset of labour in singleton gestation enrolled at term by a meta-analysis.

SEARCH STRATEGY

We performed a literature search in electronic databases.

SELECTION CRITERIA

We included only studies assessing the accuracy of TVU CL in prediction of spontaneous onset of labour in singleton gestations with vertex presentation who were enrolled at term.

DATA COLLECTION AND ANALYSIS

The primary outcome was the accuracy of CL for prediction of spontaneous labour within 7 days. Pooled sensitivities and specificities were calculated.

MAIN RESULTS

Five studies including 735 singleton gestations were included. For the prediction of spontaneous labour within 7 days for CL <30 mm the pooled sensitivity was 64% and pooled specificity was 60%. The higher the CL, the better the sensitivity; the lower the CL, the better the specificity. A woman with a singleton gestation at term and a TVU CL of 30 mm has a <50% chance of delivering within 7 days, while one with a TVU CL of 10 mm has an over 85% chance of delivery within 7 days.

CONCLUSIONS

TVU CL at term has moderate value in predicting the onset of spontaneous labour. A woman with a TVU CL of 10 mm or less has a high chance of delivering within a week.

TWEETABLE ABSTRACT

Cervical length at term has moderate value in predicting the onset of spontaneous labour.

Prediction of Preterm Delivery by Late Cervical Length Measurement after 24 Weeks

Objective: To examine the value of the cervical length (CL) measurement at 24-30 gestational weeks in the prediction of spontaneous preterm delivery (SPD) between 30 and 34 weeks (SPD34) and between 34 and 37 weeks (SPD37). Methods: We performed a prospective cross-sectional study. CL was measured once by transvaginal ultrasound examination between 24 and 30 weeks. Results: The study sample consisted of 1,180 low-risk singleton pregnancies. 10 women (0.85%) had a SPD34 and 60 (5.08%) had a SPD37. CL was shorter (p < 0.001) in the women who had a SPD34 (median 11 mm) compared to the women who delivered after 34 weeks (median 31 mm). CL was shorter (p < 0.001) in the women who had a SPD37 (median 22 mm) compared to the women who delivered after 37 weeks (median 31 mm). CL predicted SPD34 (OR = 0.837, R2 = 0.2768, AUC = 0.9406, p < 0.001) and SPD37 (OR = 0.907, R2 = 0.1085, AUC = 0.7584, p < 0.001). The model achieved a sensitivity of 70.0 and 38.3% for 10% false-positive rate for SPD34 and SPD37, respectively. Conclusions: CL after 24 weeks is significantly shorter in women destined to have a SPD. In low-risk singleton pregnancies CL performs very well in predicting SPD34 and adequately in predicting SPD37.

Predictive role of transvaginal ultrasonographic measurement of cervical length at 34 weeks for late pre-term and late-term deliveries in nulliparous women

OBJECTIVE

To investigate the predictive role of transvaginal ultrasonographic measurement of cervical length (CL) at 34 weeks of gestation in determining late-preterm and late-term deliveries in nulliparous women.

METHODS

CL was measured by transvaginal ultrasonography at 34 weeks in 318 women (singleton, nulliparous, low-risk and vertex presentation). All women were followed-up till birth and delivered at hospital. Deliveries were classifed according to gestational week as late-preterm (34(0/7) to 36(6/7) weeks), term (37(0/7) to 40(6/7) weeks) and late-term (41(0/7) to 41(6/7) weeks).

RESULTS

There was a significant correlation between CL at 34 weeks and gestational week at delivery (r = 0.614, p < 0.001). Receiver-operating characteristic curve analysis showed that CL measurement below 25.5 mm predicted late-preterm delivery with a sensitivity of 80.0%, specificity of 93.9%, positive predictive value (PPV) of 52.6% and negative predictive value (NPV) of 98.2%; while CL above 42.5 mm had 70.4% sensitivity, 93.5% specificity, 50.0% PPV and 97.1% NPV in prediction of late-term delivery.

CONCLUSION

Measurement of CL with transvaginal ultrasonography at 34 weeks of gestation can be of beneficial in predicting the risk of late-preterm and late-term deliveries in nulliparous women.

Association of Second-Trimester Cervical Length With Prolonged Pregnancy

OBJECTIVE

To estimate whether there is an association between second-trimester cervical length and prolonged pregnancy (defined as delivery at or beyond 41 weeks of gestation).

METHODS

This is a cohort study of nulliparous women with a singleton pregnancy who underwent routine cervical length measurement between 18 and 24 weeks of gestation. Women were divided into quartiles by cervical length and the association with prolonged pregnancy was evaluated in bivariable and multivariable analyses. A planned secondary analysis included only women who achieved at least 39 weeks of gestation.

RESULTS

During the study period, a total of 9,165 women met inclusion criteria, of whom 1,481 (16.2%) had a prolonged pregnancy. Women in increasing cervical length quartiles were more likely to experience a prolonged pregnancy (12.9%, 15.8%, 17.1%, 18.6%, P<.001). This association remained significant when controlling for possible confounding variables. An analysis confined to women who achieved at least 39 weeks of gestation was consistent with the overall analysis.

CONCLUSION

Increasing second-trimester cervical length is associated with an increased likelihood of having a prolonged pregnancy in nulliparous women.

LEVEL OF EVIDENCE

II.

Cervical length in late second and third trimesters: a mixture model for predicting delivery

OBJECTIVES

To examine the distribution of cervical length (CL) in the late second and third trimesters of pregnancy and construct survival models for spontaneous delivery.

METHODS

This cross-sectional study included 647 women with a singleton pregnancy who had routine CL measurements taken by transvaginal ultrasonography between 24 and 40 weeks' gestation. Only one measurement per patient was included in the analysis. Exploratory data analysis revealed that the distribution of CL measurements was a mixture of two Gaussian distributions, and subsequently a mixture model was applied to describe the distribution of CL. Changes in CL in relation to gestational age were examined by regression analysis and measurements were converted to Z-scores. Survival analysis was applied to the subgroups identified, to describe the probability of delivery throughout gestation.

RESULTS

CL was best described by a mixture model of two subgroups with Gaussian distribution, one including women with a long cervix (73.85% of the study population, mean CL of 28.2 ± 4.45 mm) and the other including women with a short cervix (26.15% of the study population, mean CL of 12.3 ± 5.14 mm). CL was dependent on gestational age (GA), therefore conversion to Z-scores was employed in the analysis. Women with a short cervix had a higher probability for spontaneous delivery (hazard ratio (HR), 1.807; P < 0.001) than did women with a long cervix, after adjustment for GA at the time of measurement (GA HR, 1.115; P < 0.001). In both subgroups, the probability of spontaneous delivery was predicted by the GA and CL Z-scores. Survival models for the prediction of spontaneous delivery were constructed separately for the short-cervix subgroup (GA HR, 1.085; P < 0.001 and CL Z-score HR, 0.819; P = 0.003) and the long-cervix subgroup (GA HR, 1.130; P < 0.001 and CL Z-score HR, 0.864; P = 0.005).

CONCLUSIONS

CL follows a mixture of two Gaussian distributions, one for a short and one for a long cervix. Late second-trimester/third-trimester CL measurement may be of value in estimating the probability for spontaneous delivery at any given gestational age.

The clinical utility of sonographic cervical length in the management of preterm parturition at 28-32 weeks of gestation

OBJECTIVES

The aim of this study was to evaluate the role of cervical length measurement in early third trimester (28-32 weeks) as a predictor of preterm delivery (PTD), in women presenting with preterm parturition.

METHODS

Cervical length was measured prospectively, in singleton pregnancies at 28-32 weeks with preterm contractions (PTC). A multivariate linear regression model was performed to assess the association between cervical length and gestational age at delivery. Logistic regression analysis with PTD before 34 and 37 weeks of gestation as the outcome variable was performed to control for confounders.

RESULTS

Fifty-six women were included, mean gestational week at presentation and at delivery were 29.88 ± 1.13 and 37.05 ± 2.86, respectively. There was a direct association between short cervical length at admission and gestational week at delivery (p = 0.027). This association remained significant even after controlling for confounders. Short cervical length was significantly associated with PTD before 34 (p = 0.045) or 37 (p = 0.046) weeks of gestation.

CONCLUSIONS

Third trimester cervical length measurement in patients with PTC is associated with gestational week at delivery, as well as PTD prior to 34 and 37 weeks of gestation. Therefore, examining cervical length is clinically valuable and probably cost-effective during early third trimester.

Association between shortened cervical length at 34-36 weeks' gestation and term labour in Asian women

Cervical length was measured at 34-36 weeks' gestation by transvaginal ultrasound. The purpose of measurement of cervical length before term was to reveal the association with the onset of term labour. This was a retrospective study of 362 women who were delivered at term at Mizmedi hospital, between August 2006 and November 2011. There was significant linear correlation between cervical length and the scan-to-labour interval in women with labour before 41 weeks. The measurement of cervical length at 34-36 weeks' gestation might be helpful in predicting the onset of term labour before 41 weeks.

Clinical and sonographic parameters at 37 weeks' gestation for predicting the risk of primary Cesarean delivery in nulliparous women

OBJECTIVES

To identify the clinical and sonographic parameters at 37 weeks' gestation that predict the risk of Cesarean delivery in labor for nulliparas.

METHODS

This prospective observational study recruited nulliparas with singleton pregnancies at 37 weeks' gestation. Determination of the Bishop score, ultrasound measurement of the cervical length, and fetal biometry were performed. The clinical parameters studied were maternal age, height and weight and Bishop score. The sonographic parameters included fetal biparietal diameter, femur length, abdominal circumference (AC), estimated fetal weight (EFW), amniotic fluid index and cervical length.

RESULTS

Four hundred and fifty-three women were examined; 57 women (12.6%) underwent an emergency Cesarean delivery in labor. Logistic regression analysis identified maternal age and height and fetal AC and EFW, but not cervical length or Bishop score, as the best predictors of Cesarean delivery. Of these predictors, maternal age and height and fetal AC at 37 weeks were included in a final model for risk scoring. The model was shown to have an adequate goodness of fit (P = 0.473), and the area under the receiver-operating characteristics curve was 0.758, indicating reasonably good discrimination.

CONCLUSIONS

Maternal age and height and fetal AC and EFW at 37 weeks' gestation are the most important parameters in predicting the risk of Cesarean delivery in nulliparas; sonographic measurement of the cervical length and the Bishop score were not predictive of Cesarean delivery. A predictive model using these parameters at 37 weeks provides useful information in the decision-making process regarding the mode of delivery.

Ultrasonographic assessment of cervix size and its correlation with female characteristics, pregnancy, BMI, and other anthropometric features

PURPOSE

Cervical length during the first trimester of pregnancy has not been completely investigated yet. The objective of our study is to compare cervical size in the first ten gestational weeks with that of non-pregnant women, and to determine its correlation with maternal factors, including age, anthropometric features, and reproductive history.

METHODS

We collected retrospective data about women who applied to the Obstetrics and Gynecology Outpatients Facility of Udine between February and June 2009, selecting both pregnant and non-pregnant women possessing a transvaginal ultrasonographic measurement of their cervix, and focusing on their age, parity, BMI, cervical, and uterine size. Data were analyzed by R (version.2.8.0), considering significant P < 0.05.

RESULTS

135 women were recruited. By multivariate linear regression, both cervical length and width result independently influenced by pregnancy status, and among non-pregnant nullipara, cervical length results to be significantly lower in women younger than 20 (P < 0.05).

CONCLUSIONS

During the first ten gestational weeks, cervix results to be longer and wider than in non-pregnant women, suggesting the possible existence of early gestational, morphological, uterine, and cervical modifications. Women under the age of 20 have a significantly shorter cervix, suggesting an incomplete cervix maturity in this group of women, which may justify the higher prevalence of pre-term births in teenage pregnancies.