Cervical funneling or intra-amniotic debris and preterm birth in nulliparous women with midtrimester cervical length less than 30 mm

Amniotic Sludge and Prematurity: Systematic Review and Meta-analysis

OBJECTIVE

 To perform a systematic review and meta-analysis of studies on maternal, fetal, and neonatal outcomes of women with singleton pregnancies, after spontaneous conception, and with the diagnosis of amniotic sludge before 37 weeks of gestational age.

DATA SOURCES

 We conducted a search on the PubMed, Cochrane, Bireme, and Theses databases until June 2022.

SELECTION OF STUDIES

 Using the keywords intra-amniotic sludge or fluid sludge or echogenic particles, we found 263 articles, 132 of which were duplicates, and 70 were discarded because they did not meet the inclusion criteria.

DATA COLLECTION

 The articles retrieved were analyzed by 2 reviewers; 61 were selected for full-text analysis, 18 were included for a qualitative analysis, and 14, for a quantitative analysis.

DATA SYNTHESIS

 Among the maternal outcomes analyzed, there was an increased risk of preterm labor (95% confidence interval [95%CI]: 1.45-2.03), premature rupture of ovular membranes (95%CI: 1.99-3.79), and clinical (95%CI: 1.41-6.19) and histological chorioamnionitis (95%CI: 1.75-3.12). Regarding the fetal outcomes, there was a significant increase in the risk of morbidity (95%CI: 1.80-3.17), mortality (95%CI: 1.14-18.57), admission to the Neonatal Intensive Care Unit (NICU; 95%CI: 1.17-1.95), and neonatal sepsis (95%CI: 2.29-7.55).

CONCLUSION

 The results of the present study indicate that the presence of amniotic sludge is a risk marker for preterm delivery. Despite the heterogeneity of the studies analyzed, even in patients with other risk factors for prematurity, such as short cervix and previous preterm delivery, the presence of amniotic sludge increases the risk of premature labor. Moreover, antibiotic therapy seems to be a treatment for amniotic sludge, and it may prolong pregnancy.

Prognosis and Prognostic Factors of Patients with Emergent Cerclage: A Japanese Single-Center Study

Objectives

The aims of this study were to clarify the following: (1) how often does prolonged pregnancy ≥34 weeks occur in patients with emergent cerclage without progesterone and (2) the risk factors preventing such pregnancy continuation.

Materials and Methods

This retrospective observational study was performed using medical records of patients for whom emergent cerclage had been performed between April 2006 and December 2018 in our institute.

Results

Emergent cerclage was performed in 123 patients (median age: 34, interquartile range: 31–36). Primiparous patients numbered 44 (36%). A history of spontaneous preterm birth (SPTB) was present in 30 (24%). The median presurgical cervical length (CL) was 16 (8–21) mm at surgery. Of the 123, 20 (16%) were delivered at 33 + 6 weeks or less (<34 weeks). We conducted logistic regression analysis of the risk factors of SPTBs <34 weeks after cerclage. Three risk factors were identified that increased the risk of SPTB <34 weeks: presurgical CL 0 mm (odds ratio (OR): 5.30; 95% confidence interval (CI): 1.58–17.7), a history of SPTB (OR: 4.65; 95% CI: 1.38–15.7), and the presence of sludge (OR: 4.14; 95% CI: 1.20–14.3).

Conclusion

Three risk factors predicted SPTB <34 weeks after emergency cerclage without progesterone administration: unmeasurable CL (CL 0 mm), a history of SPTB, and the presence of sludge on ultrasound. SPTB <34 weeks occurred after emergency cerclage in 16% of patients, being comparable with the recent data with progesterone.

Evaluation of midtrimester cervical length thresholds for the prediction of spontaneous preterm birth

INTRODUCTION

To estimate the optimal midtrimester cervical length (CL) threshold for the prediction of spontaneous preterm birth (sPTB) in asymptomatic pregnant women.

MATERIAL AND METHODS

This is a prospective observational cohort study including asymptomatic women with singleton pregnancies who underwent CL measurement by transabdominal and/or transvaginal ultrasound between 19°^/7 and 21^6/7 weeks of gestation. All CL ≤30 mm from transabdominal ultrasound were confirmed by transvaginal ultrasound. Primary outcomes were sPTB <35 and <37 weeks.

RESULTS

Out of 3,449 participants, 28 (0.8%) had a sPTB before 35 weeks and 99 (2.9%) had a sPTB before 37 weeks. Receiver operating characteristics (ROC) curves suggest that a cut-off of 30 mm was the optimal CL to predict sPTB before 35 weeks (sensitivity: 43%; specificity: 97%) and sPTB before 37 weeks (sensitivity: 21%; specificity: 97%). While a CL <25 mm was an important risk factor for sPTB before 35 weeks (relative risk: 31; 95% confidence interval: 13-73), women with a CL between 25 and 30 mm were also at greater risk (relative risk: 12; 95% confidence interval: 4 - 35) compared to women with CL ≥30 mm.

DISCUSSION

A midtrimester CL <30 mm should be considered to identify women at high-risk of sPTB.

Prediction and Prevention of Spontaneous Preterm Birth: ACOG Practice Bulletin, Number 234

Preterm birth is among the most complex and important challenges in obstetrics. Despite decades of research and clinical advancement, approximately 1 in 10 newborns in the United States is born prematurely. These newborns account for approximately three-quarters of perinatal mortality and more than one half of long-term neonatal morbidity, at significant social and economic cost (1-3). Because preterm birth is the common endpoint for multiple pathophysiologic processes, detailed classification schemes for preterm birth phenotype and etiology have been proposed (4, 5). In general, approximately one half of preterm births follow spontaneous preterm labor, about a quarter follow preterm prelabor rupture of membranes (PPROM), and the remaining quarter of preterm births are intentional, medically indicated by maternal or fetal complications. There are pronounced racial disparities in the preterm birth rate in the United States. The purpose of this document is to describe the risk factors, screening methods, and treatments for preventing spontaneous preterm birth, and to review the evidence supporting their roles in clinical practice. This Practice Bulletin has been updated to include information on increasing rates of preterm birth in the United States, disparities in preterm birth rates, and approaches to screening and prevention strategies for patients at risk for spontaneous preterm birth.

Cervical length distribution and other sonographic ancillary findings of singleton nulliparous patients at midgestation

BACKGROUND

Short cervix at midgestation, the presence of intraamniotic debris, and cervical funneling are risk factors for preterm birth; however, cervical length measurements and cutoffs are not well documented among pregnant patients of different gestational ages and self-reported races and ethnicities.

OBJECTIVE

This study aimed to describe the distribution of cervical length and frequency of funneling and debris at midgestation in nulliparous women by gestational age and race/ethnicity.

STUDY DESIGN

This secondary analysis of screening data from a multicenter treatment trial of singleton nulliparous patients with short cervix was conducted at 14 geographically distributed, university-affiliated medical centers in the United States. Singleton nulliparous patients with no known risk factors for preterm birth were screened for trial participation and asked to undergo a transvaginal ultrasound to measure cervical length by a certified sonographer. The distribution of cervical length and the frequency of funneling and debris were assessed for each gestational age week (16-22 weeks) and stratified by self-reported race and ethnicity, which for this study were categorized as White, Black, Hispanic, and other. Patients enrolled in the randomized trial were excluded from this analysis.

RESULTS

A total of 12,407 nulliparous patients were included in this analysis. The racial or ethnic distribution of the study participants was as follows: White, 41.6%; Black, 29.6%; Hispanic, 24.2%; and others, 4.6%. The 10th percentile cervical length for the entire cohort was 31.1 mm and, when stratified by race and ethnicity, 31.9 mm for White, 30.2 mm for Black, 31.4 mm for Hispanic, and 31.2 mm for patients of other race and ethnicity (P<.001). At each gestational age, the cervical length corresponding to the tenth percentile was shorter in Black patients. The 25 mm value commonly used to define a short cervix and thought to represent the 10th percentile ranged from 1.3% to 5.4% across gestational age weeks and 1.0% to 3.8% across race and ethnicity groups. Black patients had the highest rate of funneling (2.6%), whereas Hispanic and Black patients had higher rates of intraamniotic debris than White and other patients (P<.001).

CONCLUSION

Black patients had shorter cervical length and higher rates of debris and funneling than White patients. The racial and ethnic disparities in sonographic midtrimester cervical findings may provide insight into the racial disparity in preterm birth rates in the United States.

Measurement of the uterocervical angle for the prediction of preterm birth in symptomatic women

Purpose

To examine if the uterocervical angle (UCA) can be used to predict preterm delivery in women with painful and regular uterine contractions and a cervical length of 25 mm or less.

Methods

Retrospective study at the perinatal unit of the University Hospital of Tuebingen, Germany. Women with singleton gestation and preterm contractions between 24 + 0 and 33 + 6 weeks’ gestation were included. For the UCA measurement, a line is placed from the internal os to the external os irrespective of whether the cervix is straight or curved. A second line is drawn to delineate the lower uterine segment. The angle between the two lines is the UCA measurement. The measurements were taken on stored images from our database.

Results

The study consisted of 213 singleton pregnancies. At the time of UCA measurement, median maternal and gestational age was 31.4 years and 29.7 weeks’ gestation. Median gestational age at delivery was 35.3 weeks and the corresponding birth weight 2480 g, respectively. The UCA measurement in women who delivered within 2 days, between 3–7 days and after 7 days was not helpful to distinguish between these three groups [median UCA measurements: 108.5°, 108.0° and 107.3° (Kruskal–Wallis test p = 0.576)]. Uni- and multivariate logistic multiple regression analysis demonstrated that the delivery within 2 days was only dependent on the gestational age and the cervical length at the time of presentation.

Conclusion

The measurement of UCA is not useful in predicting preterm birth in the subsequent 7 days after an episode of preterm contractions.

Pessary use in patients diagnosed with short cervix and cervical insufficiency

OBJECTIVE

The aim was to evaluate the effectiveness of Arabin pessary use in patients with cervical insufficiency or short cervix before the 24th week of gestation and the impact of cervical examination findings prior to pessary application on the outcome in terms of the gestational week.

MATERIALS AND METHODS

In our study, among the pregnancies between the 12th and 24th gestational weeks, 60 pregnant women with a preterm delivery history and/or cervical length less than 25 mm were included. Among these 60 patients, 43 of them had a short cervix, 17 of them had cervical insufficiency. Routine medical and obstetric history was obtained. In the vaginal examination, the cervix was evaluated in terms of patency, dilatation, and position. Cervical length, presence of debris, and funneling were evaluated by transvaginal ultrasound. After receiving patients' approval a cervical pessary was applied to patients. Pessaries of pregnant women with 37 weeks of gestation were removed. Before reaching the 37th gestation week, pessaries were withdrawn in patients who had ongoing vaginal bleeding, premature rupture of membranes, and preterm contractions unresponsive to tocolytic treatment.

RESULTS

Thirty-one pregnant women (51.7%) out of 60 pregnant women who underwent pessary, delivered at 37 weeks and below. Delivery rates in the short cervical measurement group and cervical insufficiency group at ≤28 weeks, ≤34 weeks and ≤37 weeks were respectively (n = 21) 34.8% vs 36.3% (p = 0.976), (n = 29) 41.8% vs 64.7% (p = 0.111), (n = 31) 44.2% vs 70.6% (p = 0.888). The presence of cervical funneling before pessary application shows a statistically significant difference in terms of patient's giving birth before or after 28 weeks (p = 0.033). In patients with cervical funneling, there was a significant increase in a birth before 28 weeks. Depending on whether or not patients applying with pain need for tocolysis, it shows the statistically meaningful difference in terms of the patients giving birth before or after 34 weeks (p = 0.001) (OR 7, 61, 95% GA 2.4-24.6). In the group without the need for tocolysis, there is a meaningful increase in birth after 34 weeks.

CONCLUSIONS

Our findings showed that, alongside the defined cervical risk factors, cervical funneling and the need for tocolysis are remarkable prognostic variables in pessary application.

A new quantification system for assessing the degree of acute cervical insufficiency based on physical and sonographic examination

OBJECTIVES

Acute cervical insufficiency accounts for 10-25 % of all mid-trimester pregnancy losses. However, the definition and description for the degree of acute cervical insufficiency were obscure and different among the many studies. The aim of this study was to suggest a new 4-digit quantification system and to evaluate the outcome according to the new system in women with acute cervical insufficiency.

STUDY DESIGN

A retrospective cohort study was conducted in patients with acute cervical insufficiency who underwent physical examination indicated cervical cerclage. Acute cervical insufficiency was defined as painless external os dilation with prolapsed and/or visible membranes on speculum examination. The status of fetal membranes was described using two values: 1) size of the prolapsed membrane (P, measured using ultrasound); and 2) size of visible fetal membranes (M, evaluated by speculum examination). The status of cervix was described using two values: 1) dilatation of the narrowest os (O, measured by ultrasound); and 2) functional cervical length (C, measured by ultrasound). The patients were divided into 3 groups as follows: Stage I, patients with visible fetal membranes (M > 0) but with a remaining functional cervix (C > 0) (N = 7); stage II, those with visible fetal membranes (M > 0) and a functional cervical length of 0 but without prolapsed membranes (P = 0) (N = 33); and stage III, those with prolapsed membranes (P > 0) (N = 40).

RESULTS

1) Patients who delivered before 34 weeks of gestation had a significantly lower median gestational age at cerclage operation and a significantly higher median P, M, C values than those who delivered at or beyond 34 weeks of gestation(P < 0.01 for gestational age at operation, P and M values; P < 0.05 for C value); 2) The higher the stage based on PMOC quantification system, the greater the risk of preterm delivery before <24, <32, <34, and <37 weeks of gestation (P < 0.001 for all); 3) The neonatal survival rate was 100 % (7/7) for stage I, 93.9 % (31/33) for stage II, and 60 % (24/40) for stage III.

CONCLUSION

The PMOC system was a simple method to describe the individualized conditions and to predict the risk of preterm births in all spectrums of acute cervical insufficiency.

The impact of funneling shape on the secondary prevention of spontaneous preterm birth in patients treated with either an Arabin pessary, McDonald cerclage or early total cervical occlusion (ETCO)

OBJECTIVE

Cervical funneling is associated with spontaneous preterm birth (sPTB). The aim of this analysis was to assess the relationship between funneling shape and the response to the McDonald cerclage, the Arabin pessary and the early total cervical occlusion (ETCO).

METHODS

We retrospectively analyzed data of 312 randomly selected singleton pregnancies with cervical shortening <25 mm or normal cervical length and evaluated them according to the progression of funneling: control group (n = 46), cervical shortening without funneling (n = 107), V-shaped funneling (n = 68), U-shaped funneling (n = 47), and prolapse of the amniotic sac (n = 44). We evaluated sPTB rates <34, <28, <32, and <37 weeks as well as prolongation of gestation and birthweight.

RESULTS

Regarding the rate of sPTB <34 weeks there was no statistical significance in either of the comparisons between control group and each of the four risk groups. Regarding prolongation of gestation we demonstrated a statistical significance for all risk groups compared to the control group (all p < .05) with the lowest prolongation rate noted in the group with amnion prolapse and the highest in the group with isolated cervical shortening without funneling. Similarly, progression of funnel shape resulted in an absolute decrease of birthweight for all risk groups compared to the control group, albeit not significant for the group with U-shaped funneling (p = .1058).

CONCLUSION

Independent of the treatment, there was a significant impact of funneling shape on pregnancy duration and birthweight.

Effect of Antibiotic Treatment of Amniotic Fluid Sludge

BACKGROUND

Amniotic fluid sludge refers to the sonographic presence of echogenic, free-floating aggregates of debris located within the amniotic cavity near the internal cervical os of women with intact membranes. Clinically, it is independently associated with increased obstetric, infectious, and neonatal morbidity, including: short cervix, chorioamnionitis, and an increased risk of preterm birth. It is thought to be infectious in nature and has been described as an intrauterine bacterial biofilm. There is little evidence on the impact of treatment with antibiotics on outcome.

OBJECTIVE

To determine whether outpatient antibiotics administered to women with amniotic fluid sludge would reduce preterm birth risk compared to no antibiotic treatment.

MATERIALS AND METHODS

This was a retrospective cohort study of all patients diagnosed with amniotic fluid sludge by transvaginal sonography between 15 and 25 weeks' gestation in the outpatient ultrasound unit at a single academic center between 2010 and 2017. Patients were segregated according to whether they were treated with oral antibiotics at the time of diagnosis. Women with multiple gestation, fetal anomalies, preterm rupture of membranes prior to initial diagnosis of amniotic fluid sludge, and active preterm labor placenta previa and/or suspected accreta were excluded from analysis. Primary outcome of preterm birth at less than 37 weeks' gestation was compared by univariate and regression analysis to control for potential co-linear and/or confounding variables. Additional outcomes were compared by univariate analysis.

RESULTS

A total of 181 patients were initially identified, and 97 patients met inclusion criteria. Of these patients, 51 were treated with oral antibiotics (46 azithromycin and 5 moxifloxacin), and 46 were not treated. The overall incidence of preterm birth at <37 weeks was 49.4 % (48 of 97) and preterm birth <28 weeks was 22.7% (22 of 97). There was no significant difference in preterm birth, either at <37 weeks (P = .47) or <28 weeks (P = .83) between the treated and untreated women. After adjusting for race, body mass index, tobacco use, cervical length, and preterm birth history, antibiotic treatment did not reduce the risk of preterm birth (adjusted odds ratio, 1.3; confidence interval, 0.77-1.9). No differences were seen in the incidence of preterm premature rupture of membranes (P = .94) or median latency from diagnosis to delivery (P = .47). Birthweight (P = .99), sepsis (P = .53), intraventricular hemorrhage (P = .95), and neonatal intensive care unit (NICU) admission (P = .08) were not affected by antibiotic treatment. Antibiotic treatment did not affect the incidence of either clinical or histologic chorioamnionitis (P = .92 and .14, respectively) or histologic stage 2-3 maternal or fetal inflammation (P = .94 and 0.58, respectively). Sonographic resolution of amniotic fluid sludge on first subsequent scan was seen in 34% of antibiotic-treated women and 43% of untreated women (P = .42). There was no difference in latency from diagnosis to delivery or mean gestational age at delivery according to whether sludge resolved or persisted at the first subsequent scan (P = .14 for each).

CONCLUSION

Antibiotic treatment of amniotic fluid sludge is not associated with a reduction in premature birth. Likewise, antibiotic treatment of amniotic fluid sludge was not associated with improvement in other obstetric, neonatal, or pathologic variables. These findings suggest that the presumed infectious nature of sludge and subsequent adverse outcomes are not treated or improved by administration of azithromycin following midtrimester sonographic diagnosis.

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

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

The impact of a short cervix and funneling on the outcome in singleton pregnancies treated with an Arabin-pessary or a McDonald cerclage

OBJECTIVE

The presence of sonographic funneling is a co-predictor of spontaneous preterm birth (sPTB). The aim of this study was to assess the outcome in patients with a short cervix and funneling after a McDonald cerclage or an Arabin pessary.

METHODS

We retrospectively analyzed data of 238 singleton pregnancies with cervical shortening <25 mm subclassified by either isolated cervical shortening (n = 105) or cervical shortening and additional funneling (n = 133). In the group of isolated cervical shortening, a total of 93 patients had received a cervical pessary and 12 had McDonald cerclage. In the group of patients with additional funneling, 98 had received a cervical pessary and 35 had a cerclage. We evaluated PTB rates <28, <32, <34, and <37 weeks as well as prolongation of gestation, birth weight, and admission to NICU.

RESULTS

In the pessary groups (n = 191), funneling resulted in a significantly higher rate of PTB before 34 weeks as compared to patients with isolated cervical shortening (26.5 versus 8.6%, p=.0066). Similarly, in the cerclage groups (n = 47), funneling resulted in an absolute increase of PTB, albeit not significant (37.1 versus 0%, p=.1435) due to the smaller number. There were no significant differences in terms of prevention of PTB before 34 weeks in patients treated with pessary or cerclage, neither in the group of patients with isolated shortening nor in the group of patients with additional funneling (p=.9771 and p=.3916, respectively). However, in patients with funneling, we demonstrated a significantly lower neonatal admission rate in the pessary arm (n = 27, 27.6%) as compared to the cerclage arm (n = 31, 88.6%) (p = .0002). Similarly, the NICU admission time was shorter in both pessary groups -with and without funneling - as compared to patients treated with cerclage (p = .0000).

CONCLUSION

Pessary placement and cerclage should optimally be considered before the presence of funneling. Furthermore, there were lower rates of neonatal admission during pregnancy and a shorter admission time of babies after birth when mothers received a cervical pessary as compared to the group with cervical cerclage.