Is a full bladder still necessary for pelvic sonography?

The objective was to determine whether a full bladder is routinely necessary for a complete sonographic evaluation of the female pelvis. Over the course of 1 month, all women having a gynecologic sonogram were scanned initially transabdominally through a full bladder by the sonographer (standard images taken). A physician then joined the sonographer and scanned the patient transvaginally without prior knowledge of the findings seen transvesically. The physician finished the examination transabdominally, with the bladder empty. The physician and sonographer then determined (1) whether the scan was sufficient transvaginally only, (2) whether the scan was sufficient transvaginally and transabdominally with an empty bladder, or (3) or whether a full bladder was necessary. Two hundred and six consecutive patients were scanned prospectively. The transvaginal scan alone was sufficient to demonstrate all findings for 172 (83.5%) patients. The transvaginal and transabdominal scans through an empty bladder were needed for 31 (15.1%) patients. Three patients (1.5%) required a full bladder in addition to the other two techniques to visualize one normal ovary each. In conclusion, transvaginal scanning with an adjunctive transabdominal empty bladder approach can replace the full bladder technique for routine pelvic sonography. The transabdominal scan with an empty bladder is necessary, particularly for patients with enlarged uteri. It is no longer reasonable, however, to subject all patients undergoing pelvic sonography to bladder distention.     

Short cervix detection in pregnant women by transabdominal sonography with post-void technique

Purpose

This study aimed to evaluate the diagnostic properties of transabdominal sonography with the post-void technique for cervical length measurement.

Methods

This study was a prospective cohort study. The inclusion criteria were pregnant women aged 18–40 years with gestational age of 18–23 completed weeks. Transabdominal sonography with vertical bladder depth of less than 5 cm and transvaginal cervical length measurements were carried out by a single experienced sonographer.

Results

There were 307 eligible pregnant women. The mean age of all subjects was 29.0 years. The mean cervical length obtained through transabdominal and transvaginal measurement was 3.33 and 3.47 cm, respectively. Ten patients (3.3 %) were identified as having a short cervix using transvaginal sonography, and 12 patients (3.9 %) were identified using transabdominal sonography.

Conclusion

Transabdominal sonography with vertical bladder depth of less than 5 cm performed better compared with transvaginal sonography. It may not be necessary to perform transvaginal sonography if transabdominal sonography reveals the cervical length to be more than 2.5 cm.

     

Is Transabdominal Sonography of the Cervix After Voiding a Reliable Method of Cervical Length Assessment?

Objective. The purpose of this study was to assess the correlation and agreement between transvagi‐nal and transabdominal cervical length measurement after bladder emptying as well as the feasibility of transabdominal sonography in cervical length screening. Methods. This was a prospective cohort study involving 287 participants (14–34 weeks' gestation) from January to December 2003. After voiding, transabdominal and transvaginal cervical length measurements were obtained. The optimal trans‐abdominal technique was established during an unblinded series of transabdominal and transvaginal cervical length measurements (n = 96). The same measurements were obtained in 191 participants under a blinded 2‐sonographer protocol. The transabdominal cervical length cutoff to ensure 100% sensitivity in detecting a short cervix (≤2.5 cm) was determined. Results. There was no difference between mean transabdominal and transvaginal cervical lengths ± SD (3.57 ± 0.74 versus 3.61 ± 0.74 cm; P = .20). The Pearson correlation coefficient was 0.824. The 95% tolerance interval for any paired observation (transabdominal minus transvaginal) was ?0.92 to 0.84 cm. All transvaginal cervical lengths of 2.5 cm or less were associated with paired transabdominal cervical lengths of 3 cm or less. Conclusions. With an optimal sonographic technique, postvoid transabdominal cervical measurement shows a close correlation and agreement with transvaginal assessment and is useful for cervical length screening.     

Transvaginal and transabdominal ultrasonography of the uterine cervix during pregnancy.

Transvaginal and transabdominal ultrasound evaluation of the uterine cervix were compared in a study of 186 pregnant women. An empty bladder made transabdominal ultrasound measurement of the cervix more difficult, while bladder filling resulted in significant lengthening of the transabdominal cervical measurement. In contrast, transvaginal ultrasound cervical measurement was possible in all but 1 patient. Normal transvaginal ultrasound cervical measurements were significantly shorter on average than transabdominal cervical measurements, but compared closely with prior transabdominal ultrasound studies in which bladder filling was carefully controlled. Significant cervical shortening was not noted in most patients with a clinical diagnosis of incompetent cervix.     

Evaluation of the upper uterine cervix by the location of the vesicocervical fold of the urinary bladder to rule out cervical shortening during pregnancy with and without premature contractions.

OBJECTIVES: To measure the length of the upper and lower cervix, as demarcated anatomically by the lowermost edge of the urinary bladder, in second- and third-trimester pregnancies with and without premature contractions. We hypothesized that patients with active premature contractions have a shorter upper cervix, placing them at greater risk of preterm delivery. METHODS: The lengths of the total cervix and of the upper and lower cervix, separately, and funnelling of the internal os, were assessed by endovaginal ultrasonography. In 120 women with normal pregnancy (43 of which with premature contractions), cervical dilatation and effacement were determined by digital examination. The correlation of cervical variables with the course of pregnancy was analyzed by the Wilcoxon test. RESULTS: The mean lengths of the upper and lower cervix were 15.9 +/- 1.7 mm (median 16.0 mm) and 26.4 +/- 3.7 mm (median 27.0 mm), respectively, in patients without premature contractions and 6.9 +/- 3.7 mm (median 6.0 mm) and 24.7 +/- 4.7 mm (median 25.0 mm), respectively, in patients with premature contractions. In the latter subgroup, the upper cervix was significantly shorter (p = 0.0001) but the lower cervix remained almost unchanged. Digital palpation was less accurate than transvaginal sonography for evaluating total cervical length. CONCLUSIONS: Transvaginal sonography is the method of choice for assessing cervical changes during pregnancy. In this prospective study, upper cervical length was the best predictor of preterm labor of all cervical parameters studied. Its length could be accurately determined by the location of the lowermost edge of the urinary bladder (vesicocervical fold of the bladder).     

Comparison of transperineal and transvaginal sonography in predicting preterm delivery

PURPOSE: A major advantage of transperineal sonography (TPUS) is its ability to evaluate the cervix without causing any distortion. This study was performed to compare transvaginal sonography (TVUS) and TPUS at 24 weeks of gestation in predicting preterm delivery in low-risk pregnancy. METHODS: Three hundred fifty-seven pregnant women underwent TVUS and TPUS at 24 weeks of gestation. The relationship between cervical length and preterm delivery was assessed. Accuracy values of TVUS and TPUS at 24 weeks of gestation were compared in predicting preterm delivery. RESULTS: Preterm delivery (before 36 weeks of gestation) occurred in 22 pregnancies (6.2%). Mean cervical lengths measured by TVUS and TPUS were significantly different in preterm and term delivery groups (P < 0.05). Areas under the curves were 0.801 and 0.857 for the transvaginal and transperineal measurements, respectively. The coefficient of correlation between the transvaginal and transperineal cervical length measurements was 0.83. TPUS had a sensitivity of 77% in predicting preterm delivery, with a false-positive rate of 17% and a relative risk of 4.5 at the 32.5-mm cutoff value. CONCLUSIONS: When the cervix is well visualized, TPUS can predict preterm delivery as accurately as TVUS.     

Early prediction of preterm delivery by transvaginal ultrasonography.

The clinical value of transvaginal ultrasonography in the evaluation of the uterine cervix of pregnant women was studied. Comparison with conventional transabdominal ultrasound in 24 pregnant subjects revealed that transvaginal ultrasound was superior, because the transabdominal technique usually requires a full bladder, which causes deformation and elongation of the cervix. Digital examination showed dilatation of the internal os in only ten (38.5%) of 26 patients in whom it had previously been shown by transvaginal sonography. Transvaginal ultrasonography has the advantage of providing natural and objective information on the cervix. The values of three sonographic signs found transvaginally for predicting preterm delivery were evaluated in a total of 130 at-risk patients and 129 control subjects. Shortening of the cervical length by -1.5 SD or more was associated with an increased risk of preterm delivery (11.3% vs. 2.8%, p < 0.01). A dilated internal os of more than 5 mm before 30 weeks of gestation was associated with preterm delivery more often than an undilated internal os (33.3% vs. 3.5%, p < 0.01). Dynamic changes in the degree of dilatation of the cervical canal which were found in nine women were significantly related with preterm delivery (p < 0.05). But, in the at-risk group, only dilatation of the internal os had a predictive value for preterm birth. From these data, dilatation of the internal os on transvaginal ultrasonography was proved to be an early and important predictor of preterm delivery.     

Screening for fetal anomalies during the first trimester of pregnancy: transvaginal versus transabdominal sonography.

Ultrasound is a sensitive tool for the diagnosis of fetal anomalies during the prenatal period. Most knowledge about the ultrasound images of such anomalies is based on abdominal scanning during the second trimester of pregnancy. The value of transvaginal sonography for evaluating fetal anomalies and a comparison with transabdominal sonography in the first trimester has, to our knowledge, so far not been studied.During a 12-month period, 800 pregnant women between 9 and 13 weeks of gestation, underwent first a transabdominal scan followed by a transvaginal examination, in order to compare the value of the two techniques. Eight cases of fetal abnormality, including anencephaly, exencephaly, cervical myelomeningocele, cystic hygroma, omphalocele, posterior fossa cyst and syndactyly, were diagnosed by using the transvaginal sonographic approach. The standard abdominal technique failed to detect four of these anomalies, while in the other four only vague and non-specific fetal abnormalities could be demonstrated. All women with normal abdominal and vaginal sonograms in the first trimester were rescreened transabdominally at mid-gestation. Five patients with a variety of fetal anomalies, including hydrocephalus, agenesis of corpus callosum, bilateral ureteropelvic junction obstruction, right heart hypoplasia and tetralogy of Fallot, were identified in the rescreening procedure. One case of ventricular septal defect and coarctation of the aorta was not detected at either of the first or second screening procedures. Our findings show that transvaginal sonography is more sensitive than transabdominal sonography in the detection of first-trimester anomalies. However, since not all fetal anomalies are manifest so early in pregnancy, standard abdominal sonography in the second trimester is still recommended.     

Ultrasound imaging of paravaginal defects in women with stress incontinence before and after paravaginal defect repair.

OBJECTIVE: The aim of our study was to analyze whether transabdominal and introital sonography can identify paravaginal defects and to determine changes that occur following paravaginal defect repair and Burch colposuspension. METHODS: Twenty women with genuine stress incontinence took part in this prospective study. The mobility of the bladder neck was assessed transperineally with a curved array probe following instillation of 300 mL saline. The same probe was used transabdominally to determine the presence of paravaginal defects. Introital examination using a transvaginal probe was then performed to determine the presence of paravaginal defects. The same measurements were performed following Burch colposuspension and paravaginal defect repair. RESULTS: There were significant differences in bladder neck position and mobility before and after surgical intervention. In 18 women before surgery, transabdominal ultrasound identified unilateral or bilateral paravaginal defects. Eight unilateral defects were found on the right side but only two were found on the left side. In eight women, the defect was bilateral. The introital approach obtained similar results apart from in two patients with a bilateral defect in whom it indicated a unilateral right defect. Between the first and second weeks following the operation transabdominal ultrasound found no paravaginal defects in 16 women and introital ultrasound found no paravaginal defects in 18 women. We were unable to visualize the region of the paravaginal defect in two women using transabdominal ultrasound because the abdominal wall was edematous after surgery. Five to 6 weeks after the operation, our results were confirmed by abdominal and introital ultrasound in all cases. No paravaginal defects were found in any of the patients after paravaginal defect repair. CONCLUSION: Our clinical study suggests that ultrasound scanning should be performed to confirm the presence of paravaginal defects and that paravaginal defect repair may be added to Burch colposuspension for the treatment of genuine stress incontinence, as an operation to correct cystourethrocele and the posterior urethrovesical angle.     

Cervical length at 22-24 weeks of gestation: comparison of transvaginal and transperineal-translabial ultrasonography.

OBJECTIVES: To investigate the feasibility of measuring cervical length by transperineal or translabial sonography and compare the measurements obtained by this approach with those obtained transvaginally. METHODS: In 500 women measurement of cervical length by translabial-transperineal sonography was attempted immediately before transvaginal scanning at 22-24 (median 23) weeks of gestation. In the first phase of the study, considered to be the learning period, 200 patients were examined and their results reviewed, before carrying out the second phase in which 300 patients were examined. A comparison was made of the patient acceptability of both techniques. RESULTS: Cervical length was successfully measured transvaginally in all cases. In the first phase of the study cervical length was measured by translabial-transperineal sonography in 84% of the 200 patients but there was poor agreement with measurements obtained transvaginally and the 95% tolerance interval for paired observations was -11.0 mm to 16.1 mm. After audit of results it became apparent that the translabially-transperineally derived images were inadequate in more than half of the cases but in those with adequate paired measurements there was a very good agreement between the two and the 95% tolerance interval for paired observations was -5.8 mm to 5.2 mm. In the second phase of the study special attention was paid towards recording measurements of cervical length only in cases where both the internal and external os were adequately visualized. Successful measurements by translabial-transperineal sonography were obtained in 78% of cases and the 95% tolerance interval for paired observations was -5.8 mm to 6.1 mm. The degree of patient acceptability of the two methods was similar. CONCLUSIONS: The findings of this study suggest that at 22-24 weeks of gestation the cervix can be visualized adequately by translabial-transperineal sonography in about 80% of patients and the measurements of cervical length obtained by this approach are very similar to those obtained by transvaginal sonography.     

Cervical length for prediction of preterm birth in women with multiple prior induced abortions.

OBJECTIVE: To determine whether transvaginal sonographic cervical length predicts preterm birth in women with multiple prior induced abortions. METHODS: This was a retrospective cohort study using the Thomas Jefferson University Prematurity Database. Patients with a singleton pregnancy and a history of more than one induced abortion were identified. Exclusion criteria were cerclage and indicated preterm birth. Subjects were followed with transvaginal ultrasound measurement of the cervix between 14 and 24 weeks' gestation and grouped into those with and those without a short cervix; a cervical length of < 25 mm was considered short. The primary outcome was spontaneous preterm birth at < 35 weeks. RESULTS: Fifteen of the 65 (23%) women with more than one induced abortion included in the study had a short cervix. The demographics and risk factors were similar between those with and those without a short cervix. The overall incidence of preterm birth was 21.5% (14/65); in women with a short cervix the incidence was 47% (7/15) and in women without a short cervix it was 14% (7/50). The sensitivity, specificity and positive and negative predictive values of a short cervix in the prediction of preterm birth were 50%, 84%, 47% and 86%, respectively. The relative risk of a short cervix for spontaneous preterm birth was 3.3 (95% CI, 1.4-7.4). CONCLUSION: A cervical length of < 25 mm on transvaginal ultrasound is predictive of preterm birth in women with more than one prior induced abortion. Women with multiple prior induced abortions and a short cervix have a 3.3-fold greater chance of spontaneous preterm birth compared with those with a cervical length of > or = 25mm.     

Cervical assessment at the routine 23-week scan: standardizing techniques.

OBJECTIVE: To examine the frequency of curvature of the cervix and to establish the degree of curvature with increasing cervical length. To assess the significance of this phenomenon in terms of the classification of patients as high risk for pre-term delivery. METHOD: Cervical length was measured prospectively by transvaginal sonography in 301 women at 23 weeks of gestation. The distance between the internal and external os was measured both as a straight line and also as a curved line along the endocervical canal. In addition, a search of our database was made to identify all women who had undergone cervical assessment as part of a policy of routine screening. In those with cervical length of less than 26 mm the thermal images of the cervix were used to obtain straight and curved measurements. The frequency of curved cervix was calculated and the relationship between the ratio of straight to curved measurement to the curved one was determined. RESULTS: In the prospective study curvature of the cervix was observed in 143 (48%) of the 301 women. Curvature was observed in 51% (135 of 267) with cervical length of 26-55 mm, 25% (8 of 32) with length of 16-25 mm, and none of the two with length of 1-15 mm. The ratio of the straight to the curved measurement decreased with increasing cervical length (r = -0.27, P = 0.001). In the retrospective study curvature of the cervix was found in 72 (15%) of 471 with length of 16-25 mm and in none of the 76 with length of 1-15 mm. CONCLUSION: Cervical length is influenced by the degree of cervical curvature. The disparity of measurements between the internal and external os taken as a straight line or along the cervical canal increases with cervical length. However, this disparity may not have any clinical implications because at short cervical length (less than 16 mm) the cervix appears to be always straight.     

Biometry of early pregnancy with transvaginal sonography.

A prospective cross-sectional study was performed in 248 pregnant women between 5 and 12 weeks' menstrual age with transvaginal sonography to establish biometric charts of the gestational sac, embryonic crown-rump length and biparietal diameter, amniotic sac and yolk sac to be used for assessment of gestational age and prediction of pregnancy failure. Polynomial regression analysis was applied and demonstrated a statistically significant positive correlation that could be described in all cases as a quadratic function, between gestational age and all the measurements with the exclusion of the yolk sac. Centile charts of both growth models and dating models were tabulated. The interrelationship between different measurements, including the gestational sac, crown-rump length, biparietal diameter and amniotic sac was also evaluated to produce age-independent charts. The dating model of the crown-rump length was found to have mean values similar to those described in transabdominal studies. The 95% reference interval was, however, 8.4 days, which was not lower than those reported in most transabdominal studies. It was concluded that transvaginal sonography was more able than the abdominal route to allow measurement of the crown-rump length in very early gestation, but did not yield a greater accuracy in predicting gestational age.     

Transvaginal sonographic examination of the cervix in asymptomatic pregnant women: review of the literature.

Different strategies have been developed to refine the prediction of the risk of preterm delivery in asymptomatic patients. Transvaginal sonography has been used for this reason to measure and examine the length and shape of the cervix. In this review, we focus on clinical studies involving transvaginal sonographic assessment of the cervix in asymptomatic women at high risk of preterm delivery and in the general pregnant population. Three ultrasound signs are suggestive of cervical incompetence, namely, dilatation of the internal os, sacculation or prolapse of the membranes into the cervix (with shortening of the functional cervical length) either spontaneously or induced by transfundal pressure, and short cervix in the absence of uterine contractions. Transvaginal sonography has clearly demonstrated that cerclage leads to a measurable increase in cervical length which may contribute to the success of this procedure in reducing the risk of preterm delivery. Several non-randomized interventional studies among patients with cervical incompetence have been published. They have defined a new group of patients requiring cerclage when the women show progressive cervical modifications on transvaginal sonography, while in other studies, cerclage performed on the basis of cervical changes on transvaginal sonography did not prevent premature delivery. One prospective randomized trial in asymptomatic high-risk women has shown two benefits of cerclage following indications for transvaginal sonography: (1) it would generate fewer prophylactic cerclages in high-risk women; (2) therapeutic cerclage before 27 weeks may reduce the incidence of premature delivery before 34 weeks. The risk of preterm delivery is inversely correlated with cervical length. Routine transvaginal sonography of the cervix performed between 18 and 22 weeks can help identify patients at risk of preterm delivery. However, given the low prevalence of preterm births, screening would generate either a high false-positive rate or a low sensitivity. One non-randomized interventional study among patients with a short cervix on routine ultrasound examination found a lower risk of delivery before 32 weeks in the cerclage group than in the expectant management group. However, to date, there have been no prospective randomized trials in a general population. Although evidence is still lacking, there does appear to be a benefit in performing a cerclage rather than continuing with expectant management in cases with sonographic appearance of cervical incompetence in asymptomatic women at high risk of preterm delivery. Ultrasound can be offered to reduce the indications of cerclage for cases in which the situation is uncertain. Within the general obstetric population, transvaginal sonography might help in the selection of asymptomatic but high-risk women. However, the benefit associated with cerclage for sonographic indication has not been demonstrated.     

Cervical incompetence: the use of transvaginal sonography to provide an objective diagnosis.

OBJECTIVE: To investigate the use of transvaginal sonography in monitoring the cervix in women at high risk of a preterm delivery. STUDY DESIGN: One hundred and six women at high risk of preterm labor had regular cervical monitoring by transvaginal ultrasound throughout pregnancy from the second trimester to delivery. The study was designed to be observational, but intervention was considered if the cervical length fell below 10 mm. RESULTS: Eleven women demonstrated opening of the cervical canal at rest or with fundal pressure before 24 weeks' gestation. Between 2 and 17 days later all 11 cervices progressively shortened to a cervical length of < 10 mm. Nine women had a cervical cerclage. Seven women had fetal membranes visible within the cervical canal at the time of cerclage. One woman miscarried at 18 weeks, and the other 10 had live births at a median gestational age of 36 (range, 27-38) weeks. CONCLUSIONS: Cervical length shortening in the second trimester, once started, progressed to a cervical length under 10 mm. Opening of the cervical os at rest or in response to fundal pressure detected by transvaginal ultrasound appears to be the early ultrasound feature of cervical incompetence.     

超声检测宫颈长度预测早产的临床价值

目的探讨超声检测宫颈长度（cervicallength,CL）对先兆早产孕妇发生早产的预测价值。方法对2147例单胎先兆早产初产孕妇,分别经腹部、经阴道、经会阴超声检测CL,以CL〈2．6cm为宫颈缩短,追踪妊娠结局,比较三种方法对早产的预测价值。结果经腹部超声检测747例,CL〈2．6cm者早产率40．93％,CL≥2．6cm者早产率4．51％;经阴道超声检测689例,CL〈2．6cm者早产率69．85％,CL≥2．6cm者早产率1．45％;经会阴超声检测711例,CL〈2．6cm者早产率61．54％;CL≥2．6cm者早产率1．98％,三种检测方法检测的CL〈2．6cm组与CL≥2．6cm组的早产率差异均有统计学意义（P〈0．05）;经腹部、经阴道、经会阴超声测量预测早产的敏感性分别为78．57％、92．23％、89．72％,特异性分别为80．00％、93．00％、90．07％,阳性预测值分别为40．93％、69．85％、61．54％,阴性预测值分别为95．49％、98．55％、98．02％,经会阴、经阴道超声测量预测早产的敏感性、特异性、阳性预测值、阴性预测值均显著高于经腹部（P〈0．05）。结论超声检测CL对先兆早产孕妇发生早产有一定的预测意义。经会阴、经阴道超声预测早产的准确性优于经腹部超声。经会阴超声检测可以替代经阴道超声检测,从而提高患者治疗依从性。     

Reliability and validity of two methods of three-dimensional cervical volume measurement.

OBJECTIVES: To determine if cervical length obtained with three-dimensional ultrasound correlated with the 'true cervical volume' and to evaluate the reliability and validity of transabdominal and transvaginal three-dimensional cervical volume measurement. METHODS: This was a prospective observational study. Three-dimensional cervical volume measurements were made prior to hysterectomy in 28 women. Following hysterectomy the amputated cervical volume was calculated using water displacement. For the assessment of intra- and interobserver reliability, the intraclass correlation coefficient (ICC) was used. The index of concordance between the sonographic cervical volumes and those obtained by the reference standard (true cervical volume) was assessed with the limits of agreement method and the ICC. RESULTS: Transabdominal cervical length and transvaginal cervical length correlated moderately with actual cervical volume; correlation coefficients were 0.64 and 0.57 (P < 0.05), respectively. Intraobserver reliability for both transabdominal and transvaginal cervical volume assessment was good (> 0.75). Interobserver reliability for transvaginal cervical volumes was similarly good (ICC = 0.90). However, for transabdominal measurements the interobserver reliability was poor (ICC = 0.51). The validity of both methods of three-dimensional volume assessment was poor (ICC < 0.75). This was reflected in the wide limits of agreement, which ranged from approximately - 25 mL to + 30 mL. CONCLUSION: The reliability and validity of three-dimensional cervical volume measurement are poor. Clinical introduction of cervical volume measurement should be avoided at this time.     

Transvaginal sonography of the uterine cervix prior to labor induction.

OBJECTIVES: To compare the Bishop score and transvaginal sonographic measurement of cervical length for predicting the mode of delivery following medically indicated induction of labor in term patients. METHODS: The study was conducted prospectively in 179 women who required medically indicated induction of labor. Inclusion criteria were singleton pregnancy, gestational age > 37 weeks of amenorrhea, cephalic presentation and intact fetal membranes. Cervical length was measured upon arrival in the labor room but was not considered when choosing the induction procedure. Two receiver-operating characteristic curves were plotted to calculate the best threshold value for the Bishop score and for cervical length for predicting the risk of Cesarean section. RESULTS: Fifty-three women (29.6%) had a Cesarean section. The Bishop score was not predictive of the delivery mode, although Cesarean section for failure to progress was more frequent when the Bishop score was < or = 5. Among the women with a Bishop score > 5, the cervical length was not predictive of the induction outcome. However, among the women with a Bishop score < or = 5, a cervical length < 26 mm was associated with a lower Cesarean section rate (20.6 vs. 42.9%; P = 0.006). Furthermore, the interval between the beginning of cervical ripening and delivery was shorter in the case of a short cervix (11.01 +/- 6.7 vs. 18.55 +/- 7.07 h; P < 10(-5)). CONCLUSION: The length of the uterine cervix, measured by transvaginal sonography, is a better predictor of the risk of Cesarean section than the Bishop score after induction of labor for medical reasons. In women with an unfavorable Bishop score, a cervical length of < 26 mm is associated with a lower risk of Cesarean section and a shorter duration of labor.     

Cervical length evaluation by transvaginal sonography in nongravid women with a history of preterm delivery.

OBJECTIVE: To evaluate cervical length in the nongravid period in women with a past history of preterm delivery. METHODS: The study population comprised 54 women who had delivered spontaneously before 34 weeks of gestation. Etiology of preterm delivery was suspected to be related to cervical incompetence, defined as a painless and progressive dilatation of the cervix in the absence of other causes. Patients with pre-eclampsia, intrauterine growth restriction, uterine anomalies, fetal anomalies, multiple gestation and similar complications were excluded. Shortening of the cervix was recorded during pregnancy in all study patients. One hundred and four women matched for age, parity and body mass index who had given birth at term served as the control group. Cervical length was evaluated in all women at least 12 weeks after delivery by transvaginal sonography in the mid-sagittal plane. RESULTS: The mean gestational age at delivery was 30.8 +/- 1.2 weeks in the study group and 38.8 +/- 2.1 weeks in the control group (P = 0.03). The mean cervical length in the two groups was 36 +/- 6 and 38 +/- 4 mm, respectively. This difference was not statistically significant (P = 0.9). CONCLUSIONS: In nongravid women with unexplained preterm delivery there is no difference in cervical length compared to patients who deliver at term. Shortening of the cervix is most probably a reversible phenomenon that occurs during pregnancy and represents a failure of the competence mechanism to adapt to pregnancy.     

Cervical length, multifetal pregnancy reduction, and prediction of preterm birth

PURPOSE: To evaluate the application of transvaginal sonography assessment of cervical length before fetal reduction for predicting spontaneous preterm birth in triplet gestations reduced to twins. METHODS: This retrospective study was conducted at the ultrasound unit of a university-affiliated municipal hospital. The study cohort consisted of 25 women with triplet gestations following ovulation induction or assisted-reproduction techniques who underwent fetal reduction to twins. Cervical length was assessed via transvaginal sonography before fetal reduction, and data on pregnancy outcome were retrieved from maternal records and/or maternal interviews. RESULTS: Cervical length (mean +/- SD) at reduction was 4.0 +/- 0.85 (range: 1.2-5.5). Five women were excluded from statistical evaluation because pregnancy complications precluded spontaneous delivery. Two of 3 (67%) women with a cervical length of <3.5 cm delivered prior to 33 weeks' gestation compared with 1/17 (6%) women with a cervical length > or = 3.5 cm. This difference was statistically significant (P < 0.05). The sensitivity, specificity, positive predictive value, and negative predictive value of cervical lengths <3.5 cm to predict delivery prior to 33 gestational weeks was 67%, 94%, 67%, and 94%, respectively. CONCLUSIONS: Measurement of cervical length in triplet pregnancies before fetal reduction provides useful predictive information on the risk for preterm delivery.