Prediction of preterm delivery with transvaginal ultrasonography of the cervix in patients with high-risk pregnancies: does cerclage prevent prematurity?

OBJECTIVES: We sought to determine the predictive accuracy for preterm delivery of transvaginal ultrasonography of the cervix between 14 and 24 weeks' gestation in high-risk patients and to determine whether cerclage prevents preterm delivery in patients with ultrasonographic cervical changes. STUDY DESIGN: Patients with asymptomatic singleton pregnancies at high risk for preterm delivery were followed prospectively from 14 weeks' to 23 weeks 6 days' gestation with transvaginal ultrasonography of the cervix. The subgroup of patients with either a cervical length of <25 mm or funneling of >25% or both was offered McDonald salvage cerclage, which was performed at the discretion of the patient and the obstetrician. The 2 groups (with and without cerclage) were compared for the primary outcome of preterm delivery at <35 weeks' gestation. RESULTS: One hundred sixty-eight women were followed, including 97 (58%) with >/=1 prior 14- to 34-week preterm deliveries. Of 63 (37. 5%) patients identified as having cervical changes, 23 (37%) had preterm delivery; of 105 patients with no cervical changes, 8 (8%) had preterm delivery (relative risk, 4.8; 95% confidence interval, 2. 3-10.1). The sensitivity, specificity, and positive and negative predictive values of either a short cervix of <25 mm or funneling of >25% or both were 74%, 70%, 37%, and 92%, respectively. Of 63 pregnancies in which there were cervical changes, 39 underwent cerclage and 24 did not. These 2 groups were similar for demographic characteristics, risk factors, and transvaginal ultrasonographic cervical length and funneling but dissimilar for gestational age at identification of cervical changes (18.3 vs 21.2 weeks' gestation in the groups with and without cerclage, respectively; P <.001). Multivariate logistic regression analysis after adjustment for gestational age at cervical changes showed no difference in the rate of preterm delivery between the groups with and without cerclage (odds ratio, 1.1; 95% confidence interval, 0.3-4.6). Stratified analysis of patients identified between 18 and 24 weeks revealed 22 pregnancies with cerclage and 22 pregnancies without cerclage, which was similar for all characteristics studied. The incidence of preterm delivery remained similar (27% vs 23%, respectively; P =.7), as did days from cervical changes to delivery (111 vs 96, respectively; P =.2). CONCLUSIONS: Transvaginal ultrasonography of the cervix between 14 and 24 weeks' gestation is a good predictor of preterm delivery in high-risk pregnancies. Cerclage may not prevent preterm delivery in patients identified to be at high risk for this outcome by transvaginal ultrasonography.     

Final results of the Cervical Incompetence Prevention Randomized Cerclage Trial (CIPRACT): therapeutic cerclage with bed rest versus bed rest alone.

OBJECTIVE: To compare preterm delivery rates (before 34 weeks of gestation) and neonatal morbidity and mortality in patients with risk factors or symptoms of cervical incompetence managed with therapeutic McDonald cerclage and bed rest versus bed rest alone. STUDY DESIGN: Cervical length was measured in patients with risk factors or symptoms of cervical incompetence. Risk factors for cervical incompetence included previous preterm delivery before 34 weeks of gestation that met clinical criteria for the diagnosis of cervical incompetence, previous preterm premature rupture of membranes before 32 weeks of gestation, history of cold knife conization, diethylstilbestrol exposure, and uterine anomaly. When a cervical length of <25 mm was measured before a gestational age of 27 weeks, a randomization for therapeutic cerclage and bed rest (cerclage group) or bed rest alone (bed rest group) was performed. The analysis is based on intention to treat. RESULTS: Of the 35 women who met the inclusion criteria, 19 were allocated randomly to the cerclage group and 16 to the bed rest group. Both groups were comparable for mean cervical length and mean gestational age at time of randomization, mean overall 20 mm and 21 weeks. Preterm delivery before 34 weeks was significantly more frequent in the bed rest group than in the cerclage group (7 of 16 vs none, respectively; P =.002). There was no statistically significant difference in neonatal survival between the groups (13 neonates survived in the bed rest group vs all in the cerclage group). The compound neonatal morbidity, defined as admission to the neonatal intensive care unit or neonatal death, was significantly higher in the bed rest group than in the cerclage group (8 of 16 vs 1 of 19, respectively; P =.005; RR = 9.5, 95% CI, 1.3-68.1). CONCLUSIONS: Therapeutic cerclage with bed rest reduces preterm delivery before 34 weeks of gestation and compound neonatal morbidity in women with risk factors and/or symptoms of cervical incompetence and a cervical length of <25 mm before 27 weeks of gestation.     

Patients with prior second-trimester loss: prophylactic cerclage or serial transvaginal sonograms?

OBJECTIVE: To compare management with prophylactic cerclage versus serial transvaginal sonograms of the cervix in patients with prior second-trimester loss. STUDY DESIGN: Singleton pregnancies with prior second-trimester spontaneous loss between 14 and 24 weeks' gestation were retrospectively reviewed. At the obstetricians' discretion, some were managed with prophylactic cerclage and some with serial transvaginal sonograms of the cervix, starting at 14 weeks, and cerclage only if cervical length was <25 mm or funneling was >25% before 24 weeks. All cerclages were McDonald. Primary outcome was preterm delivery at <35 weeks. RESULTS: Of 177 patients with singleton pregnancies who had prior second-trimester loss identified, 66 received prophylactic cerclage and 111 were followed up with transvaginal sonography, of which 36% (40/111) had therapeutic cerclage because of cervical changes. The two management groups of prophylactic cerclage versus transvaginal sonography of the cervix did not differ in any measure of obstetric outcome, including preterm delivery at <35 weeks (23% vs 30%; P =.3), preterm delivery at <33 weeks (21% vs 26%; P =.5), or gestational age at delivery (34.6 +/- 6.8 weeks vs 34.4 +/- 6.8 weeks; P =.8). CONCLUSION: In patients with prior second-trimester loss, serial transvaginal sonography of the cervix, with cerclage only if indicated by cervical changes, is a valuable alternative to a policy of uniform prophylactic cerclage.     

Cervical incompetence: a reappraisal of an obstetric controversy

Cervical incompetence is not a categoric but rather a continuous variable, meaning that there are various degrees in the competency of the cervix. Furthermore, a certain degree of competency of the cervix can be expressed differently in subsequent pregnancies. Women with risk factors for cervical incompetence in their gynecological/obstetric history should be followed by transvaginal ultrasonography. History alone is not an indication for a prophylactic cerclage. Although transvaginal ultrasonography identifies women at high risk of preterm delivery, it does not discriminate between different underlying pathologies. Short cervical length alone is not an indication for a therapeutic cerclage. Serial transvaginal ultrasonographic measurements of cervical length in women with risk factors can identify those women truly at high risk of preterm delivery. A transvaginal cervical cerclage with bed rest reduces preterm delivery and improves perinatal outcome in women with a short cervical length and risk factors for cervical incompetence. TARGET AUDIENCE: Obstetricians & Gynecologists, Family Physicians. LEARNING OBJECTIVES: After completion of this article, the reader will be able to define cervical incompetence, explain the role of transvaginal ultrasonography in the prediction of preterm delivery, and summarize the data on the use of transvaginal cervical cerclage.     

Does cervical cerclage prevent preterm delivery in patients with a short cervix?

OBJECTIVE: Our purpose was to determine whether cerclage placement in women with a short cervix on transvaginal ultrasonography reduces the rate of preterm delivery. STUDY DESIGN: A retrospective cohort study identified patients with an ultrasonographic short cervix (cervical length < or =15 mm) between 14 and 24 weeks' gestation. Cerclage placement was performed at the discretion of the attending physician. Clinical characteristics and outcome with and without cerclage were compared. RESULTS: Seventy patients met inclusion criteria; 25 (36%) underwent cerclage placement. Patients managed with cerclage had a lower gestational age at diagnosis (19.6 weeks vs 21.3 weeks, P <.01) but had a similar median cervical length, presence of funneling, and a history of cervical surgery, in comparison with those managed without cerclage. The rate of spontaneous preterm delivery was not different between groups. Patients with cerclage had a higher rate of preterm premature rupture of membranes than those without cerclage (65.2% vs 36.4%, P <.05). CONCLUSION: Cervical cerclage in patients with a short cervix did not reduce the rate of spontaneous preterm delivery and increased the risk of preterm premature rupture of membranes.     

Cervical cerclage and evidence-based medicine: if, how and when

Cervical cerclage has always been the main treatment option in cases of so-called cervical insufficiency, a condition that is notoriously associated with a high risk of second trimester abortion and/or preterm delivery. We can distinguish between a prophylactic cerclage, to be performed electively, usually at 13-16 weeks gestation, only when the woman has a history extremely suggestive for cervical incompetence (3 or more mid-trimester abortions or preterm deliveries) and a therapeutic cerclage. This last cerclage is recommended either for women who have ultrasonographic changes consistent with a short cervix or the presence of funneling after the 16-20 weeks gestation (urgent cerclage) and for women who present the asymptomatic dilation of the uterine cervix of at least 2 cm and/or a prolapse of the amniochorial membranes (emergent cerclage). So far there is still a lack of controlled and randomized trials that can unquestionably demonstrate the advantages of the cervical cerclage in comparison with a 'wait and see' aptitude. The cerclage can be performed either transvaginally, usually according to the McDonald technique, or transabdominally. This last approach is recommended when a transvaginal cerclage has to be avoided because of technical difficulties depending on the conditions of the cervix or when the pregnant woman has a history of one or more failed transvaginal cerclages. Interesting perspectives are currently offered by the laparoscopic cerclage, a method that has been effective and unexpectedly safe till now.     

The prevalence and timing of cervical cerclage placement in multiple gestations.

OBJECTIVES: To investigate the prevalence and timing of cervical cerclage placement in multiple gestations. METHODS: Our perinatal database was queried for all multiple gestations delivered at Evanston Hospital from 12/95 through 12/00. This list was then cross-matched with billing and medical records for 'incompetent cervix' and 'cerclage.' The medical records of all deliveries /=14 weeks over a 5-year period. The number of patients that underwent cerclage placement was 29 or 3.6%. The mean gestational age at cerclage placement was 18.6+/-4.5 weeks (range 11-24.6). Twelve were elective or prophylactic while 17 were 'urgent' or 'emergent.' The mean gestational age for the 17 emergent cerclages was 21.4+/-2.2 weeks (range 16.6-24.6). When compared with those patients who did not undergo cerclage placement, there was no difference in maternal demographics including age, parity, or previous full-term delivery. There was a significant difference in the gestational age at delivery for the cerclage vs. no cerclage group; 29.3+/-5.6 vs. 34.4+/-4.6 weeks, respectively, and in the frequency of losses at 相似文献   

Short cervical length by ultrasound and cerclage.

OBJECTIVE: To determine whether gravidas with short cervical length on endovaginal ultrasound examination, not in preterm labor, who underwent cervical cerclage have better outcomes compared with those with no cerclage. METHODS: This is an observational study in which data were collected prospectively on women who had ultrasound endovaginal cervical length measurement and were not in preterm labor. The subgroup of women who were < or = 26 weeks' at cervical measurement was analyzed separately. Short cervix was defined as < or = 30 mm. After delivery, charts were reviewed for management and outcomes, performed at the discretion of the attending obstetrician. Two study groups were defined: those with cerclage and those with no cerclage. Predictor variables were cerclage and cervical lengths. Outcome variables were birth weight, gestational age at delivery, and neonatal outcomes. Data were analyzed using the chi-squared, Fisher's exact, and Student's t-tests, a p value of < 0.05 was considered to be significant. RESULTS: A total of 85 patients with cervical lengths of < or = 30 mm were identified; of these 43 had cerclage, and 42 did not. The latter had bedrest, tocolytics, or no intervention. Indications for cervical length measurement were similar in both groups, as were age, insurance status, cervical measurements, preterm premature rupture of membranes, and mode of delivery. The mean gestational age at delivery and birth weight in the cerclage group (34.0 +/- 5.4 weeks'; 2530 +/- 905 gm) were greater than in the no cerclage group (32.0 +/- 6.0 weeks', 2084 +/- 1085 gm, p values of < 0.04 and < 0.04, respectively). Analysis for the subgroup of women who were < or = 26 weeks at first measurement revealed similar results. The relative risk for delivering at < 30 weeks' gestation, for incrementally shorter cervices, was less in the cerclage group. CONCLUSION: Cerclage in gravidas with short cervix measured by endovaginal ultrasound, not in preterm labor, may be associated with neonates of greater gestational age and birth weight, with fewer of these parturients delivering before 30 weeks' gestation. A prospective randomized trial of treatment modalities for asymptomatic shortened cervix is needed.     

Cervical incompetence prevention randomized cerclage trial: emergency cerclage with bed rest versus bed rest alone

OBJECTIVE: The purpose of this study was to compare preterm delivery rates and neonatal morbidity/mortality rates for women with cervical incompetence with membranes at or beyond a dilated external cervical os that was treated with emergency cerclage, bed rest plus indomethacin, versus just bed rest. STUDY DESIGN: Women with cervical incompetence with membranes at or beyond a dilated external cervical os, before 27 weeks of gestation, were treated with antibiotics and bed rest and randomly assigned for emergency cerclage and indomethacin or bed rest only. RESULTS: Twenty-three women were included; 13 women were allocated randomly to the emergency cerclage and indomethacin group, and 10 women were allocated randomly to the bed rest-only group. Gestational age at time of randomization was 22.2 weeks in the emergency cerclage and indomethacin group and 23.0 weeks in the bed rest-only group. Mean interval from randomization until delivery was 54 days in the emergency cerclage and indomethacin group and 20 days in the bed rest-only group (P=.046). Mean gestational age at delivery was 29.9 weeks in the emergency cerclage and indomethacin group and 25.9 weeks in the bed rest-only group. Preterm delivery before 34 weeks of gestation was significantly lower in the emergency cerclage and indomethacin group, with 7 of 13 deliveries versus all 10 deliveries in the bed rest-only group (P=.02). CONCLUSIONS: Emergency cerclage, indomethacin, antibiotics, and bed rest reduce preterm delivery before 34 weeks compared with bed rest and antibiotics alone.     

A randomized trial of cerclage versus no cerclage among patients with ultrasonographically detected second-trimester preterm dilatation of the internal os

OBJECTIVE: The aim of this study was to compare perinatal outcomes of patients with second-trimester ultrasonographic evidence of preterm dilatation of the internal os treated with cerclage versus those of patients not treated with cerclage. STUDY DESIGN: From May 1998 through June 1999 patients with ultrasonographic evidence of preterm dilatation of the internal os between 16 and 24 weeks' gestation were randomly assigned to receive a McDonald cerclage or no cerclage. Before random assignment all patients underwent amniocentesis and urogenital cultures and then received 48 hours of therapy with indomethacin and antibiotics. After treatment each patient was followed up as an outpatient with bed rest and weekly ultrasonographic evaluation. RESULTS: Of the 61 patients 31 were randomly assigned to cerclage and 30 were randomly assigned to no cerclage. There were no differences between groups with respect to maternal demographic characteristics, risk factors for preterm birth, cervical measurements, rescue procedures, readmission, chorioamnionitis, and abruptio placentae. The mean gestational age at delivery (33.5 +/- 6.3 weeks) and the perinatal death rate (12. 9%) in the cerclage group were similar to the mean gestational age at delivery (34.7 +/- 4.7 weeks; P =.4) and the perinatal death rate (10.0%; P =.9) in the no-cerclage group. CONCLUSION: Treatment with McDonald cerclage of preterm dilatation of the cervix detected ultrasonographically during the second trimester did not improve perinatal outcomes.     

Change in cervical length after cerclage as a predictor of preterm delivery

OBJECTIVE: To determine whether the degree of cervical lengthening after cerclage and whether serial follow-up measurements of cervical length after cerclage are predictive of pregnancy outcome. METHODS: Eighty women whose primary physician determined that a prophylactic (n = 50) or urgent cerclage (n = 30) was indicated had transvaginal ultrasonographic evaluation before and after cerclage. Thereafter, most women had three additional transvaginal ultrasound examinations until 32 weeks' gestation. At each examination, the mean of three measurements was calculated. Statistical analyses were done by t test, analysis of variance, and logistic regression, with significance set at P <.05. RESULTS: The mean +/- standard deviation precerclage cervical length was 27.2 +/- 10.3 mm and after cerclage was 34.1 +/- 9.9 mm (n = 80, P <.001, paired t test). No significant association was found (r = -0.26) between the difference in cervical length (postcerclage - precerclage lengths) and pregnancy outcome. Patients with a prophylactic cerclage had a mean cervical length that was consistently longer in patients delivering at term compared with those who delivered preterm at 20 to 32 weeks' gestation. In the urgent cerclage group a significant difference in cervical length between those who delivered at term compared with preterm was evident only at 28 to 32 weeks. CONCLUSION: The increase in cervical length after cerclage is not predictive of term delivery. Serial cervical length measurements in the late second or early third trimester predict preterm birth but could provide earlier warning in patients with a prophylactic cerclage than in patients with urgent cerclage.     

Cervical cerclage for prevention of preterm delivery: meta-analysis of randomized trials

OBJECTIVE: To estimate the effectiveness of prophylactic and therapeutic cerclage by meta-analysis of randomized clinical trials. DATA SOURCES: We searched the Cochrane Pregnancy and Childbirth Group specialized register of clinical trials (May 2002). Congress proceedings of international society meetings of fetal-maternal and reproductive medicine were searched by hand. METHODS OF STUDY SELECTION: Meta-analysis of randomized clinical trials comparing cervical cerclage with expectant management during pregnancy was performed. Further clarification was sought from trial authors when required. TABULATION, INTEGRATION, AND RESULTS: Six trials describing a total of 2175 women were analyzed. Prophylactic cerclage was compared with no cerclage in four trials. Pooled results failed to show a statistically significant reduction in pregnancy loss and preterm delivery rates, although a small reduction in births less than 33 weeks' gestation was seen in the largest trial (relative risk [RR] 0.75; 95% confidence interval [CI] 0.58 to 0.98). Cervical cerclage was associated with mild pyrexia, increased use of tocolytic therapy, and hospital admission but no serious morbidity. Two trials examined the role of therapeutic cerclage when ultrasound examination revealed a short cervix. Pooled results failed to show a reduction in total pregnancy loss, early pregnancy loss, or preterm delivery before 28 and 34 weeks in women assigned to cervical cerclage. CONCLUSION: The effectiveness of prophylactic cerclage in preventing preterm delivery in women at low or medium risk for second-trimester pregnancy loss has not been proven. The role of cerclage in women whose ultrasound reveals short cervix remains uncertain.     

Patients with a prior failed transvaginal cerclage: a comparison of obstetric outcomes with either transabdominal or transvaginal cerclage

OBJECTIVE: Our purpose was to compare the incidence of preterm birth after a prior failed vaginal cerclage in patients who had a subsequent transabdominal or a transvaginal cerclage. STUDY DESIGN: We conducted a retrospective cohort study of singleton pregnancies in women who had undergone (9-14 weeks) either a transabdominal or a transvaginal prophylactic cerclage after >/=1 prior failed transvaginal cerclage. Prior failed transvaginal cerclage was defined as a preterm birth at <33 weeks' gestation in the immediate prior pregnancy despite a transvaginal cerclage. All transabdominal cerclage procedures were performed by a single attending physician (George Davis, DO). Patients with a cervix too short for transvaginal cerclage placement, placenta previa, or major fetal anomalies were excluded. Primary outcome was preterm birth at <35 weeks' gestation. RESULTS: Forty transabdominal and 24 transvaginal cerclage pregnancies were analyzed. These 2 groups were similar in race and payer status but differed in age (34.0 +/- 4.2 vs 31.3 +/- 4.6 years, respectively; P =.01). The transabdominal cerclage group had more prior failed cerclage procedures per patient (1.8 +/- 1.0 vs 1.1 +/- 0.3; P =.02) and more prior 14- to 24-week spontaneous abortions per patient (2.4 +/- 1.3 vs 1.5 +/- 1.0; P =.02) than the transvaginal cerclage group. Preterm delivery at both <35 and <33 weeks' gestation was less common in the transabdominal cerclage group (18% vs 42%, P =.04; 10% vs 38%, P =.01; respectively) than in the transvaginal cerclage group. Gestational age at delivery was 36. 3 +/- 4.1 weeks in the transabdominal cerclage group and 32.8 +/- 8. 6 weeks in the transvaginal cerclage group (P =.03). Preterm premature rupture of membranes also occurred less often in the transabdominal cerclage group than in the transvaginal cerclage group (8% vs 29%, P =.03). CONCLUSION: In patients with a prior failed transvaginal cerclage, transabdominal cerclage is associated with a lower incidence of preterm delivery and preterm premature rupture of membranes in comparison with transvaginal cerclage.     

宫颈环扎术在早产治疗中的应用

目的评估治疗性宫颈环扎术及预防性宫颈环扎术的效果。方法选择2003年1月至2006年3月北京大学第三医院的34周前的早产临产及宫颈机能不全患者,早产临产患者采取紧急宫颈环扎术联合宫缩抑制剂或者单纯使用宫缩抑制剂治疗。宫颈机能不全患者采取预防性宫颈环扎术、紧急环扎术以及非环扎保守治疗。对治疗结局进行统计学分析。结果在早产临产组,紧急宫颈环扎联合宫缩抑制剂（硫酸镁）来治疗早产,平均保胎天数45.00 d,较单纯用宫缩抑制剂硫酸镁抑制宫缩的34例患者保胎天数[中位数为1（0.75-16）d]明显延长,34、37周后分娩率分别为66.7%（26/39）、30.8%（12/39）,明显增加。宫颈机能不全患者预防性环扎及治疗性环扎均较非环扎组保胎天数延长,增加32、34周后的分娩率（P〈0.05）,但治疗性环扎可降低早产率（P=0.02）。结论观察资料结果显示早产临产患者硫酸镁联合宫颈环扎治疗早产效果更佳,增加34周以上的分娩率,降低早产率;预防性环扎不能降低37周前早产率,但能增加32、34周后分娩率,延长保胎天数;治疗性环扎可降低37周前早产率。     

Transvaginal ultrasonography of the cervix length and the prediction of preterm delivery

OBJECTIVE: To determine if cervical shortening between 12 and 28 weeks gestation predicts risk of spontaneous preterm birth or cervical funneling requiring cerclage. STUDY DESIGN: We reviewed retrospectively all the patients who had transvaginal cervical ultrasound assessment during one year. 43 patients who had a second and early third trimester delivery or cerclage placement were chosen for the study. The control group consisted of 78 patients without signs of preterm labor and cervical shortening as assessed by transvaginal ultrasound. The results of the last ultrasound cervical length measurement were correlated with the likelihood of preterm delivery or cervical funneling requiring cerclage. RESULTS: 26 of 121 patients studied delivered preterm and 15 required cervical cerclage because of cervical shortening and funneling. The mean cervical length assessed by ultrasound was 23.22 +/- 3.07 mm in the group with preterm contractions and delivery and 21.99 +/- 7.05 mm in the group with cervical incompetence. In the normal pregnancy group mean cervical length was 35.59 +/- 3.07 mm. CONCLUSIONS: Cervical length of < 3.0 cm and further shortening of the cervix is predictive of preterm delivery or cervical incompetence requiring cerclage.     

Use of cervical ultrasonography in prediction of spontaneous preterm birth in twin gestations

OBJECTIVE: This study was undertaken to compare various ultrasonographic cervical parameters with respect to ability to predict spontaneous preterm birth in twin gestations. STUDY DESIGN: This prospective study involved 131 women carrying twins who were longitudinally evaluated on 524 occasions between 15 and 28 weeks' gestation with transvaginal cervical ultrasonography and transfundal pressure. The following cervical parameters were obtained: funnel width and length, cervical length, percentage of funneling, and cervical index. Receiver operating characteristic curve analysis was used to determine the ultrasonographic cervical parameter evaluated at 15 to 20 weeks' gestation, 21 to 24 weeks' gestation, and 25 to 28 weeks' gestation that were best for prediction of spontaneous preterm birth at <28 weeks' gestation, <30 weeks' gestation, <32 weeks' gestation, and <34 weeks' gestation. RESULTS: The median gestational age at delivery was 36 weeks' gestation (range, 21-41 weeks' gestation). Receiver operating characteristic curve analysis indicted that a cervical length of < or =2.0 cm, regardless of gestational age category at cervical measurement, was at least as good as other ultrasonographic cervical parameters at predicting spontaneous preterm birth. Between 15 and 20 weeks' gestation a cervical length cutoff value of < or =2.0 cm had specificities of 97%, 98%, 99%, and 100% and negative predictive values of 99%, 98%, 95%, and 89% for delivery at <28, <30, <32, and <34 weeks' gestation, respectively. The positive predictive values for delivery at <32 and <34 weeks' gestation were 80% and 100%, respectively. Between 21 and 24 weeks' gestation a cervical length of < or =2.0 cm had specificities of 84%, 84%, 85%, and 86% and negative predictive values of 99%, 99%, 94%, and 87% for delivery at <28, <30, <32, and <34 weeks' gestation, respectively. Between 25 and 28 weeks' gestation cervical length had excellent negative predictive values of 99%, 98%, 95%, and 93% for delivery at <28, <30, <32, and <34 weeks' gestation, respectively. CONCLUSIONS: In twin gestations a cervical length of < or =2.0 cm measured between 15 and 28 weeks' gestation was at least as good as other ultrasonographic cervical parameters at predicting spontaneous preterm birth. The high specificities indicate that cervical length was better at predicting the absence than the presence of various degrees of spontaneous prematurity.     

Ultrasonic assessment of cervix in "at risk" patients

One hundred seventy patients were considered to be at risk of cervical incompetence from their previous history. They were scanned serially from the first trimester to 36 weeks gestation. Of the 170, 105 patients (61.8%) were found to have defective cervix (the length of cervix, width of the cervix, and cervical canal at the level of the internal cervical os, and herniation of amniotic membrane with or without fetal parts into the cervical canal). Of the 105 patients diagnosed to have defective cervix (possible cervical incompetence), 22 patients (21%) aborted, 48 patients (45.7%) had to have cervical cerclage, 26 patients (24.8%) had preterm delivery and the remaining 9 patients (8.5%) had no problems during pregnancy. The remaining 65 patients (38.2%) did not have ultrasonic evidence of cervical incompetence and 3 aborted and only 2 patients delivered between 35 and 37 weeks gestation while 60 patients delivered between 37 and 42 weeks gestation. These 65 patients would have had cervical cerclage on the basis of the clinical history alone, but in only 6, cervical cerclage was inserted.     

Noninvasive cerclage for the management of cervical incompetence: a prospective study

Objective: The aim of this study was to evaluate the efficacy and safety of a noninvasive cerclage pessary in the management of cervical incompetence. Methods: This is a prospective cohort study of all pregnant women treated for cervical incompetence during a 4-year period. Women with known risk factors for preterm delivery had transvaginal ultrasonography every 2–3 weeks after 17–19 weeks of gestation. Those with progressive shortening of cervix diagnosed before 30 weeks were treated with a cerclage pessary when the cervical length was ≤25 mm. The pessary was electively removed at 34–36 weeks. The course and outcome of pregnancy were recorded. Results: Thirty-two women were treated with a cerclage pessary. There were nine twin and two triplet pregnancies. Fifteen (47%) had two or more risk factors for preterm delivery. The mean gestational age at cerclage was 23 (17–29) weeks, cervical length 17 (5–25) mm. Two women required delivery before the onset of labor due to severe intrauterine growth restriction and one due to HELLP syndrome. These were excluded from further analysis. In the remaining 29 women, the interval between cerclage and delivery was 10.4 (2–19) weeks, mean gestational age at delivery 34 (22–42) weeks, and birth weight 2,255 (410–4,045) g. Thirteen (45%) women delivered before 34 weeks. There were a total of 35 live-born infants and four intrapartum fetal deaths (all between 22 and 25 weeks gestation). All women complained of increased vaginal discharge, but no other significant complications were observed that could be attributed to the use of pessary. Conclusion : Cerclage pessary may be useful in the management of cervical incompetence. Whether it can be a noninvasive alternative to surgical cerclage merits further investigation.     

Effect of cerclage on obstetrical outcome in twin gestations with a shortened cervical length

OBJECTIVE: Our purpose was to determine the impact of cerclage placement on obstetric outcome in twin gestations with a shortened cervical length. STUDY DESIGN: A prospective cohort study of 147 consecutive twin pregnancies (July 1994 to March 2001) who underwent transvaginal ultrasonographic cervical length measurement between 18 and 26 weeks' gestation. Cerclage was offered to women with cervical lengths < or = 25 mm. Patients were segregated into quartiles by cervical length. Regression analysis and chi(2) tests were used to determine the effect of cervical length and cerclage on parameters of prematurity. RESULTS: One hundred twenty-eight twin gestations met inclusion criteria, including 21 (16.4%) who underwent cerclage for a cervical length < or = 25 mm. Decreasing cervical length was significantly associated with a shorter length of gestation, lower combined birth weight, delivery at < or = 34 weeks, preterm premature rupture of fetal membranes, and very low birth weight. None of these outcomes was altered by cerclage placement. CONCLUSION: Midtrimester cerclage does not alter the risks of prematurity associated with a shortened cervical length in twin gestations.     

Fetal fibronectin as a predictor of spontaneous preterm labour in asymptomatic women with a cervical cerclage

Objective  To assess the accuracy of fetal fibronectin (fFN) testing for prediction of preterm labour in asymptomatic high-risk women with a cervical cerclage.
Design  Retrospective observational study.
Setting  United Kingdom.
Population  Nine hundred and ten asymptomatic women at high-risk of Preterm birth referred to specialist antenatal clinics and undergoing fFN testing between November 1997 and December 2007.
Methods  Women had fFN tests taken between 23⁺⁰ and 27⁺⁶ weeks' gestation, on one or more occasions.
Main outcome measures  Sensitivity, specificity, positive predictive values and negative predictive values of fFN testing for predicting delivery <30 and <37 weeks were compared in those with and without cerclage.
Results  For delivery <30 weeks' gestation, the specificity of fFN testing was significantly lower in women with cervical cerclage (77% vs 90%; P  ≤ 0.00001). The sensitivity of the test was similar between the groups (78.6 (no-cerclage) vs 60% (cerclage); P  > 0.4). The negative predictive value of the fFN test for delivery <30 weeks was high in both groups (>98%).
Conclusions  Asymptomatic high-risk women with cerclage in situ are more likely to have a false positive fFN test. The negative predictive value is similar.