Improving the screening accuracy for preterm labor: is the combination of fetal fibronectin and cervical length in symptomatic patients a useful predictor of preterm birth? A systematic review

Cervical sliding sign; does it have a contribution in cases of threatened preterm labor in singleton pregnancies with intact membranes?

OBJECTIVE

To investigate the contribution of the cervical sliding sign to conventional cervical length measurement in patients at risk of preterm labor.

METHODS

The study, performed as a prospective cohort study, included patients admitted to a tertiary research hospital with a diagnosis of threatened preterm labor. The participants were divided into two groups: those who gave birth before and after 37 weeks of gestation. The clinical and demographic characteristics, cervical length, presence of a short cervix (SC), and cervical sliding sign (CSS) were compared between the groups. Furthermore, correlation and regression analyses were conducted to investigate the relationship between the presence of a SC, the presence of CSS, and the coexistence of these two findings with preterm delivery, as well as the interval between the symptoms and delivery being less than four weeks.

RESULTS

The study included 77 patients who delivered prematurely and 65 patients who delivered at term. The following variables were significantly lower in the preterm delivery group: cervical length, gestational age at delivery, neonatal weight, and time between the first examination and delivery (p = 0.003, <0.001, <0.001 and < 0.001, respectively). A higher percentage of women in the preterm delivery group exhibited a diagnosis of a SC, the presence of CSS, and the coexistence of both conditions (p = 0.002, 0.012 and 0.018, respectively). The results of the logistic regression analysis indicated that the odds ratios for preterm delivery were 3.3 in the presence of a SC alone, 2.67 in the presence of CSS alone, and 2.85 in the association of both findings (p = 0.003, 0.013 and 0.021 respectively). The odds ratios for delivery in less than four weeks were 3.08 in the presence of a SC alone, 3.4 in the presence of CSS alone, and 3.54 in the association of both findings (p = 0.004, 0.002 and 0.005 respectively).

CONCLUSION

In singleton pregnant women presenting with threatened preterm labor, the presence of CSS is associated with an increased risk of preterm delivery and a decreased presentation-to-delivery interval. However, its contribution to conventional cervical length measurement appears to be relatively limited.

Cervical Length Ultrasound for the Evaluation of Preterm Labor: A Survey of National Use and Review of Evidence

OBJECTIVE

The objective of this study was to survey national utilization of cervical length (CL) ultrasound on labor and delivery (L&D) for the evaluation of preterm labor (PTL) and identify provider attitudes and barriers to utilization.

STUDY DESIGN

Survey was emailed to Obstetrics and Gynecology Residency and Maternal-Fetal Medicine Fellowship program and advertised via links on obstetric-related Facebook interest groups. The survey was open from August 4, 2020 to January 4, 2021. Characteristics between respondents who did and did not report the use of CL ultrasound for PTL evaluation were compared with chi-square analysis.

RESULTS

There were 214 respondents across 42 states. One hundred and thirty-four respondents (63%) reported any use of CL in the evaluation of PTL and eighty (37%) denied it. There was a significant difference in practice location, practice type, delivery volume, and region between those who did and did not utilize CL ultrasound on L&D. Those who did use CL ultrasound were more likely to report no barriers to use (40 vs. 4%, p < 0.001). The most common barriers involved the availability of transvaginal ultrasound (31%), sterilization of transvaginal ultrasound probe (32%), limited availability of persons able to perform/interpret CL imaging (38%). Nineteen percent believed CL ultrasound had little/no utility in clinical practice. Those who did not use CL ultrasound in the evaluation of PTL were significantly more likely to report the feeling that there was little/no utility of CL ultrasound in clinical practice (37 vs. 7%, p < 0.001) and to report transvaginal ultrasound availability as barriers to use (63 vs. 12%, p < 0.001).

CONCLUSION

CL ultrasound is used nationally in PTL evaluation. However, significant barriers limit widespread adoption. These barriers can be addressed through the dissemination of information and practice guidelines, addition of CL ultrasound education in residency training and through CME opportunities after training, and providing support/resources/access for those looking to add this tool to their practice environment.

KEY POINTS

· In a national survey, 63% of obstetricians endorsed any use of cervical length (CL) ultrasound for preterm labor evaluation on labor and delivery.. · The most common barriers involved the availability of transvaginal ultrasound (31%), sterilization of transvaginal ultrasound probe (32%), limited availability of persons able to perform/interpret CL imaging (38%).. · Those who did not use CL ultrasound in the evaluation of PTL were significantly more likely to report the feeling that there was little/no utility of CL ultrasound in clinical practice and to report transvaginal ultrasound availability as barriers to utilization.. · Barriers to utilization of CL ultrasound for preterm labor evaluation can be addressed through practice guidelines, ultrasound education, and support for equipment/training necessary for use..

Clinical application of amino-terminal pro-brain natriuretic peptide concentration in amniotic fluid for the prediction of preterm birth in symptomatic women

BACKGROUND

Preterm birth accounts for 60% to 80% of neonatal mortality. Approximately one-third of preterm births are caused by the spontaneous onset of preterm labor. Nevertheless, 70% to 90% of women diagnosed with preterm labor will not deliver within 7 days. Thus, many women will be unnecessarily treated by preterm labor with risk medications. Better tools are needed to categorize women in preterm labor into high or low risk of preterm delivery.

OBJECTIVE

This study aimed to evaluate the amino-terminal pro-brain natriuretic peptide concentration in the amniotic fluid as a prognostic test to predict the risk of delivery within 48 hours or 7 days and before 34 0/7 or 37 0/7 weeks of gestation in women in preterm labor.

STUDY DESIGN

A total of 102 pregnant women presenting signs and symptoms of spontaneous preterm birth (22 0/7 to 34 0/7 weeks of gestation) were included. Amniotic fluid was obtained by amniocentesis, and amino-terminal pro-brain natriuretic peptide concentration was measured. Below normal concentration was defined as <0.5 multiples of the median of the standard curve according to gestational age. The risk of preterm delivery was estimated according to normal or lower-than-normal amino-terminal pro-brain natriuretic peptide concentrations. The predictive capacity of the test (below normal amino-terminal pro-brain natriuretic peptide concentration) was evaluated to identify spontaneous preterm birth at 48 hours or 7 days from amniocentesis and less than 34 0/7 or 37 0/7 weeks at delivery.

RESULTS

For the outcome delivery within 48 hours, lower-than-normal amino-terminal pro-brain natriuretic peptide concentration had 94.6% sensitivity, 73.8% specificity, 96.0% negative predictive value, 3.61 positive likelihood ratio, and 0.07 negative likelihood ratio. For the outcome delivery within 7 days, the test had 93.9% sensitivity, 88.7% specificity, 94.0% negative predictive value, 8.31 positive likelihood ratio, and 0.07 negative likelihood ratio. For the outcomes of spontaneous preterm birth before 34 0/7 and 37 0/7 weeks of gestation, below normal amino-terminal pro-brain natriuretic peptide concentrations had 80.0% sensitivity, 83.0% specificity, 78.0% negative predictive value, 4.70 positive likelihood ratio, and 0.24 negative likelihood ratio and 64.1% sensitivity, 91.7% specificity, 44.0% negative predictive value, 7.70 positive likelihood ratio, and 0.39 negative likelihood ratio, respectively.

CONCLUSION

Among patients in spontaneous preterm labor, the detection of lower-than-normal amino-terminal pro-brain natriuretic peptide concentrations (<0.5 multiples of the median) in amniotic fluid has an excellent predictive capacity to identify those patients at low risk of preterm delivery within 48 hours or 7 days.

Management of preterm labor: Clinical practice guideline and recommendation by the WAPM-World Association of Perinatal Medicine and the PMF-Perinatal Medicine Foundation

This practice guideline follows the mission of the World Association of Perinatal Medicine in collaboration with the Perinatal Medicine Foundation, bringing together groups and individuals throughout the world, with the goal of improving the management of preterm labor. In fact, this document provides further guidance for healthcare practitioners on the appropriate use of examinations with the aim to improve the accuracy in diagnosing preterm labor and allow timely and appropriate administration of tocolytics, antenatal corticosteroids and magnesium sulphate and avoid unnecessary or excessive interventions. Therefore, it is not intended to establish a legal standard of care. This document is based on consensus among perinatal experts throughout the world in the light of scientific literature and serves as a guideline for use in clinical practice.

Benefits of Premaquick® Combined Detection of IL-6/Total IGFBP-1/Native IGFBP-1 to Predict Preterm Delivery

We conducted a prospective double-blind study to compare two vaginal diagnostic methods in singleton pregnancies with threatened preterm labor (TPL) at the University Hospital of Clermont-Ferrand (France) from August 2018 to December 2020. Our main objective was to compare the diagnostic capacity at admission, in terms of positive predictive value (PPV) and negative predictive value (NPV), of Premaquick® (combined detection of IL-6/total IGFBP-1/native IGFBP-1) and QuikCheck fFN™ (fetal fibronectin) for delivery within 7 days in cases of TPL. We included 193 patients. Premaquick® had a sensitivity close to 89%, equivalent to QuikCheck fFN™, but a higher statistical specificity of 49.5% against 38.6% for QuikCheck fFN™. We found no superiority of Premaquick® over QuickCheck fFN™ in terms of PPV (6.6% vs. 7.9%), with NPV being equivalent in predicting childbirth within 7 days in cases of TPL (98.6% vs. 98.9%). Nevertheless, the combination of positive native and total IGFBP-1 and the combination of all three positive markers were associated with a higher PPV. Our results, though non-significant, support this combined multiple-biomarker approach to improve testing in terms of predictive values.

Short-term effects of tropospheric ozone and other environmental factors on emergency admissions due to pregnancy complications: A time-series analysis in the Madrid Region

Air pollution has been linked to adverse neonatal outcomes, mainly in the case of prolonged exposures. This study focuses on the short-term effects on maternal health. We conducted a retrospective ecological time-series study in the Madrid Region covering the period 2013-2018. The independent variables were mean daily concentrations of tropospheric ozone (O3), particulate matter (PM10/PM2.5) and nitrogen dioxide (NO2), as well as noise levels. The dependent variables were daily emergency hospital admissions due to complications in pregnancy, childbirth and the puerperium. Poisson generalised linear regression models were fitted to quantify the relative and attributable risks, controlling for trend, seasonality, the autoregressive nature of the series, and a number of meteorological factors. There were 318 069 emergency hospital admissions due to obstetric complications across the 2191 days of study. Of this total: 13 164 (95%CI: 9930-16 398) admissions were attributable to exposure to O3, the only pollutant to show a statistically significant (p < 0.05) association with admissions due to hypertensive disorders; and 10 575 (95%CI: 3573-17 566) admissions were attributable to daytime noise levels, while admissions due to hyperemesis gravidarum and vomiting were related to exposure to night noise. Other pollutants which also displayed statistically significant associations were: NO2 concentrations, with admissions due to vomiting and preterm labour; PM10 concentrations, with premature rupture of membranes: and PM2.5 concentrations, with total complications. Exposure to a range of air pollutants, and ozone in particular, is associated with a higher number of emergency hospital admissions due to gestational complications. Hence, surveillance of environmental effects on maternal health should be intensified, and plans and strategies to minimise these should be drawn up.

Antenatal Corticosteroid Prophylaxis at Late Preterm Gestation: Clinical Guidelines vs Clinical Practice

OBJECTIVES

We investigated how the Antenatal Late Preterm Steroids (ALPS) trial findings have been translated into clinical practice in Canada and the United States (U.S.).

METHODS

The study included all live births in Nova Scotia, Canada and the United States from 2007 to 2020. ACS administration within specific categories of gestational age was assessed by calculating rates per 100 live births, and temporal changes were quantified using odds ratios (OR) and 95% CI. Temporal trends in optimal and suboptimal ACS use were also assessed.

RESULTS

In Nova Scotia, the rate of any ACS administration increased significantly among women delivering at 35⁰ to 36⁶ weeks, from 15.2% in 2007-2016 to 19.6% in 2017-2020 (OR 1.36, 95% CI 1.14-1.62). Overall, the U.S. rates were lower than the rates in Nova Scotia. In the U.S., rates of any ACS administration increased significantly across all gestational age categories: among live births at 35⁰ to 36⁶ weeks gestation, any ACS use increased from 4.1% in 2007-2016 to 18.5% in 2017-2020 (OR 5.33, 95% CI 5.28-5.38). Among infants between 24⁰ and 34⁶ weeks gestation in Nova Scotia, 32% received optimally timed ACS, while 47% received ACS with suboptimal timing. Of the women who received ACS in 2020, 34% in Canada and 20% in the U.S. delivered at ≥37 weeks.

CONCLUSION

Publication of the ALPS trial resulted in increased ACS administration at late preterm gestation in Nova Scotia, Canada and the U.S. However, a significant fraction of women receiving ACS prophylaxis delivered at term gestation.

Predicting preterm births from electrohysterogram recordings via deep learning

About one in ten babies is born preterm, i.e., before completing 37 weeks of gestation, which can result in permanent neurologic deficit and is a leading cause of child mortality. Although imminent preterm labor can be detected, predicting preterm births more than one week in advance remains elusive. Here, we develop a deep learning method to predict preterm births directly from electrohysterogram (EHG) measurements of pregnant mothers recorded at around 31 weeks of gestation. We developed a prediction model, which includes a recurrent neural network, to predict preterm births using short-time Fourier transforms of EHG recordings and clinical information from two public datasets. We predicted preterm births with an area under the receiver-operating characteristic curve (AUC) of 0.78 (95% confidence interval: 0.76-0.80). Moreover, we found that the spectral patterns of the measurements were more predictive than the temporal patterns, suggesting that preterm births can be predicted from short EHG recordings in an automated process. We show that preterm births can be predicted for pregnant mothers around their 31st week of gestation, prompting beneficial treatments to reduce the incidence of preterm births and improve their outcomes.

Developing a risk profile for spontaneous preterm birth and short interval to delivery among patients with threatened preterm labor

BACKGROUND

Threatened preterm birth is the most common reason for antepartum hospitalization in the United States, accounting for approximately 50% of these admissions. However, fewer than 10% of patients with inpatient evaluation for signs or symptoms of preterm labor ultimately deliver before term.

OBJECTIVE

This study aimed to generate predictive models to assess the risk of preterm delivery and time to delivery based on clinical signs and symptoms of patients evaluated in our institution for preterm labor concerns.

STUDY DESIGN

This was a retrospective cohort study of singleton pregnancies evaluated for signs and/or symptoms of preterm labor, including contractions, abdominal pain, vaginal bleeding, and short cervix, between 22 0/7 and 33 6/7 weeks of gestation. Inpatient evaluations were classified by patient presentation: (1) symptomatic with cervical findings (transvaginal cervical length of <2.5 cm or cervical dilation of ≥2.0 cm), (2) asymptomatic with cervical findings, and (3) symptomatic without cervical findings. The primary outcomes included incidence of spontaneous preterm birth and interval from presentation to delivery, compared between groups. The risk of preterm delivery was evaluated using log-binomial regression, and presentation to delivery timing was assessed by survival analysis and Cox proportional hazards modeling.

RESULTS

Of 631 patients with preterm labor concerns, 96 (16%) were symptomatic with cervical findings on evaluation, 51 (8%) were asymptomatic with cervical findings, and 466 (76%) were symptomatic without cervical findings. The occurrence of preterm birth was significantly higher among symptomatic patients with cervical findings (49%) than among those with cervical findings alone (31%) or symptoms alone (11%) (P<.0001). In addition, symptomatic patients with cervical findings were significantly more likely to deliver within 48 hours (20%), 1 week (30%), 2 weeks (33%), and 1 month (43%) of presentation than patients with cervical findings alone (2%, 2%, 6%, and 10%, respectively) or symptoms alone (0.4%, 1%, 1.5%, and 5%, respectively) (P value for trend<.0001). Adjusted for gestational age at presentation and previous preterm birth, the overall risk of preterm delivery was significantly higher among patients with symptoms and cervical findings than among patients with cervical findings alone (relative risk, 2.81; 95% confidence interval, 1.74-4.54) or symptoms alone (relative risk, 4.39; 95% confidence interval, 3.16-6.09). Adjusted for the same variables, symptomatic patients with cervical findings were also at higher risk of delivery over time after assessment than patients with cervical findings alone (hazard ratio, 2.06; 95% confidence interval, 1.47-2.90) or symptoms alone (hazard ratio, 2.16; 95% confidence interval, 1.74-2.70). The negative predictive value of these models suggested that only 1% of patients with isolated symptoms or cervical findings are at risk of preterm delivery within 1 week of initial presentation.

CONCLUSION

Symptomatic patients with cervical findings suggestive of preterm labor were at the greatest risk of preterm birth and a shorter interval from presentation to delivery. The study findings supported a risk profile that may facilitate the selection of patients most appropriate for admission and targeted management. Nonetheless, as nearly 50% of patients meeting this risk profile subsequently deliver at term, future research is needed to identify which of these patients will require intervention.

The use of antenatal corticosteroids for fetal maturation: clinical practice guideline by the WAPM-World Association of Perinatal Medicine and the PMF-Perinatal Medicine foundation

This practice guideline follows the mission of the World Association of Perinatal Medicine in collaboration with the Perinatal Medicine Foundation, bringing together groups and individuals throughout the world, with the goal of improving the use of antenatal corticosteroids (ACS) for fetal maturation. In fact, this document provides further guidance for healthcare practitioners on the appropriate use of ACS with the aim to increase the timely administration and avoid unnecessary or excessive use. Therefore, it is not intended to establish a legal standard of care. This document is based on consensus among perinatal experts throughout the world and serves as a guideline for use in clinical practice.

Identifying Preterm Labor Evaluation Visits and Extraction of Cervical Length Measures from Electronic Health Records Within a large Integrated Healthcare System (Preprint)

Background

Preterm birth (PTB) represents a significant public health problem in the United States and throughout the world. Accurate identification of preterm labor (PTL) evaluation visits is the first step in conducting PTB-related research.

Objective

We aimed to develop a validated computerized algorithm to identify PTL evaluation visits and extract cervical length (CL) measures from electronic health records (EHRs) within a large integrated health care system.

Methods

We used data extracted from the EHRs at Kaiser Permanente Southern California between 2009 and 2020. First, we identified triage and hospital encounters with fetal fibronectin (fFN) tests, transvaginal ultrasound (TVUS) procedures, PTL medications, or PTL diagnosis codes within 24^0/7-34^6/7 gestational weeks. Second, clinical notes associated with triage and hospital encounters within 24^0/7-34^6/7 gestational weeks were extracted from EHRs. A computerized algorithm and an automated process were developed and refined by multiple iterations of chart review and adjudication to search the following PTL indicators: fFN tests, TVUS procedures, abdominal pain, uterine contractions, PTL medications, and descriptions of PTL evaluations. An additional process was constructed to extract the CLs from the corresponding clinical notes of these identified PTL evaluation visits.

Results

A total of 441,673 live birth pregnancies were identified between 2009 and 2020. Of these, 103,139 pregnancies (23.35%) had documented PTL evaluation visits identified by the computerized algorithm. The trend of pregnancies with PTL evaluation visits slightly decreased from 24.41% (2009) to 17.42% (2020). Of the first 103,139 PTL visits, 19,439 (18.85%) and 44,423 (43.97%) had an fFN test and a TVUS, respectively. The percentage of first PTL visits with an fFN test decreased from 18.06% at 24^0/7 gestational weeks to 2.32% at 34^6/7 gestational weeks, and TVUS from 54.67% at 24^0/7 gestational weeks to 12.05% in 34^6/7 gestational weeks. The mean (SD) of the CL was 3.66 (0.99) cm with a mean range of 3.61-3.69 cm that remained stable across the study period. Of the pregnancies with PTL evaluation visits, the rate of PTB remained stable over time (20,399, 19.78%). Validation of the computerized algorithms against 100 randomly selected records from these potential PTL visits showed positive predictive values of 97%, 94.44%, 100%, and 96.43% for the PTL evaluation visits, fFN tests, TVUS, and CL, respectively, along with sensitivity values of 100%, 90%, and 90%, and specificity values of 98.8%, 100%, and 98.6% for the fFN test, TVUS, and CL, respectively.

Conclusions

The developed computerized algorithm effectively identified PTL evaluation visits and extracted the corresponding CL measures from the EHRs. Validation against this algorithm achieved a high level of accuracy. This computerized algorithm can be used for conducting PTL- or PTB-related pharmacoepidemiologic studies and patient care reviews.

Clinicians' experiences of using and implementing a medical mobile phone app (QUiPP V2) designed to predict the risk of preterm birth and aid clinical decision making

Background

As the vast majority of women who present in threatened preterm labour (TPTL) will not deliver early, clinicians need to balance the risks of over-medicalising the majority of women, against the potential risk of preterm delivery for those discharged home. The QUiPP app is a free, validated app which can support clinical decision-making as it produces individualised risks of delivery within relevant timeframes. Recent evidence has highlighted that clinicians would welcome a decision-support tool that accurately predicts preterm birth.

Methods

Qualitative interviews were undertaken as part of the EQUIPTT study (The Evaluation of the QUiPP app for Triage and Transfer) (REC: 17/LO/1802) which aimed to evaluate the impact of the QUiPP app on management of TPTL. Individual semi-structured telephone interviews were used to explore clinicians’ (obstetricians’ and midwives’) experiences of using the QUiPP app and how it was implemented at their hospital sites. Thematic analysis was chosen to explore the meaning of the data, through a framework approach.

Results

Nineteen participants from 10 hospital sites in England took part. Data analysis revealed three overarching themes which were: ‘experience of using the app’, ‘how QUiPP risk changes practice’ and ‘successfully adopting QUiPP: context is everything’. With these final themes we appeared to have achieved our aim of exploring the clinicians’ experiences of using and implementing the QUiPP app.

Conclusion

This study explored different clinician’s experiences of implementing the app. The organizational and cultural context at different sites appeared to have a large impact on how well the QUiPP app was implemented. Future work needs to be undertaken to understand how best to embed the intervention within different settings. This will inform scale up of QUiPP app use across the UK and ensure that clinicians have access to this free, easy-to-use tool which can positively aid clinical decision making when caring for women in TPTL.

Clinical trial registry and registration number

ISRCTN 17846337, registered 08th January 2018, https://doi.org/10.1186/ISRCTN17846337.

Availability and use of fetal fibronectin testing and transvaginal ultrasound for preterm labor evaluation in the United States

OBJECTIVE

Measure availability and use of fetal fibronectin (fFN) testing and transvaginal ultrasound to measure cervical length (TVCL) for symptomatic preterm labor (PTL) patients. Additionally, assess the presence and impact of PTL triage protocols.

STUDY DESIGN

Cross-sectional online survey among clinicians from 255 unique hospitals regarding prior 12-month practices (pre-COVID-19).

RESULTS

fFN testing was always available in 87% (221) of hospitals, while TVCL was always available in 69% (175) of hospitals. Utilization was lower: fFN specimens were often/always collected in 61% (156) of hospitals and TVCL was often/always performed in 43% (110) of hospitals. fFN testing was significantly more likely than TVCL to be available and used (p < .05). Written PTL protocols were available in 47% (121) of hospitals but not consistently followed.

CONCLUSION

The most accurate risk assessment approach for imminent spontaneous preterm birth is the implementation of a universal screening program for symptomatic patients, including fFN testing and TVCL.

Guideline No. 401: Sonographic Cervical Length in Singleton Pregnancies: Techniques and Clinical Applications

OBJECTIVES

• To assess the association between sonography-derived cervical length measurement and preterm birth. • To describe the various techniques to measure cervical length using sonography. • To review the natural history of the short cervix. • To review the clinical uses, predictive ability, and utility of sonography-measured short cervix.

OUTCOMES

Reduction in rates of prematurity and/or better identification of those at risk, as well as possible prevention of unnecessary interventions.

INTENDED USERS

Clinicians involved in the obstetrical management or cervical imaging of patients at increased risk of a short cervix.

TARGET POPULATION

Women at increased risk of a short cervix or at risk of preterm birth.

EVIDENCE

Literature published up to June 2019 was retrieved through searches of PubMed and the Cochrane Library using appropriate controlled vocabulary and key words (preterm labour, ultrasound, cervix, cervical insufficiency, transvaginal, transperineal, cervical length, fibronectin). Results were restricted to general and systematic reviews, randomized controlled trials, controlled clinical trials, and observational studies. There were no date or language restrictions. Grey (unpublished) literature was identified through searching the websites of health technology assessment agencies, clinical practice guideline collections, clinical trial registries, and national and international medical specialty societies.

VALUES

The evidence and this guideline were reviewed by the Diagnostic Imaging Committee of the Society of Obstetricians and Gynaecologists of Canada, and the recommendations were made and graded according to the rankings of the Canadian Task Force on Preventive Health Care (Online Appendix Table A1).

BENEFITS, HARMS, COSTS

Preterm birth is a leading cause of perinatal morbidity and mortality. Use of the sonographic technique reviewed in this guideline may help identify women at risk of preterm birth and, in some circumstances, lead to interventions that may reduce the rate of preterm birth. SUMMARY STATEMENTS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES): RECOMMENDATIONS (CANADIAN TASK FORCE ON PREVENTIVE HEALTH CARE GRADING IN PARENTHESES).

Impact of a medical mobile phone app (QUiPP) for predicting preterm birth on the anxiety and decisional conflicts faced by women in threatened preterm labour

BACKGROUND

The QUiPP app is a free, validated mobile phone application (app) that supports clinical decision-making for women in threatened preterm labour by providing an individualised risk of delivery within clinically important time points. Alongside generating a percentage risk score, the QUiPP app also provides the risk score in an infographic donut chart, allowing the clinician to communicate with the woman in an easy to understand format. Informing women of their risk status using the QUIPP app may help to reduce anxiety in women and decrease decisional conflict.

METHOD

A subset of participants from the EQUIPTT study [REC Ref. 17/LO/1802] were asked to complete a questionnaire booklet which was used to evaluate decisional conflict and anxiety. Seven sites were randomised to the QUiPP app intervention (to use as a decision and communication tool) and six sites were randomised to the control (continued their normal practice). The first section of the questionnaire booklet was completed by the woman before her assessment, and the second section after. The pre and postassessment anxiety scores utilised the Visual Analogue Scale for Anxiety (Hornblow and Kidson, 1976). The Decisional Conflict Scale (O'Connor, 1995) measured decisional conflict post assessment. The data were then analysed to determine the impact of the QUiPP App on the anxiety and decisional conflicts faced by women in threatened preterm labour.

RESULTS

Questionnaires were completed by 221 women from 12 of the potential 13 sites. After exclusions 202 questionnaires were included in the analysis. There was a significant reduction in difference between anxiety scores before and after clinical assessment. While there were reductions in anxiety and decisional conflict for women who were aware of the QUiPP app use, this failed to reach statistical significance.

CONCLUSIONS

The QUiPP app has potential to reduce anxiety and decisional conflict in women who are aware that it is being used in their care. Additional work is required to ensure clinicians are aware of the QUiPP app and optimise using it as a communication tool when counselling women.

Cervicovaginal fluid cytokines as predictive markers of preterm birth in symptomatic women

Objective

Here, we investigated whether cytokines in the cervicovaginal fluid (CVF) can be predictive markers of preterm birth (PTB).

Methods

A multi-center prospective cohort study was conducted on 59 singleton pregnant women hospitalized for preterm labor (PTL) and/or preterm premature rupture of membranes (pPROM) between 22 weeks and 36 weeks 6 days of gestation from 2014 to 2015. The levels of 13 inflammatory cytokines (macrophage inflammatory protein [MIP]-1α, MIP-1β, tumor necrosis factor [TNF]-α, interleukin [IL]-1β, IL-6, IL-8, IL-17α, granulocyte colony stimulating factor [G-CSF], IL-7, IL-4, IL-5, IL-10, and IL-13) were measured using a multiplex bead-based immunoassay and that of fetal fibronectin (fFN) was measured using enzyme-linked immunosorbent assay (ELISA). Statistical analyses were performed using Student’s t-test, Mann-Whitney U test, Pearson’s correlation, and receiver operating characteristic (ROC) curve analysis in SPSS version 20.0.

Results

Among the 13 cytokines assessed, the levels of 3 cytokines (MIP-1α, IL-6, and IL-7) were negatively correlated with gestational age at delivery (P=0.028, P=0.002, and P=0.018, respectively). Sensitivities of MIP-1α, IL-6, and IL-17α were 70%, 80%, and 75%, respectively, and their specificities were 57%, 65%, and 69%, respectively. The sensitivity and specificity of fFN were 33% and 95%, respectively.

Conclusion

In symptomatic women diagnosed with PTL and/or pPROM, cytokines from cervicovaginal fluid, especially IL-6 and IL-17α, could be better predictive markers of PTB than fFN.

Development and validation of predictive models for QUiPP App v.2: tool for predicting preterm birth in women with symptoms of threatened preterm labor

OBJECTIVE

To develop enhanced prediction models to update the QUiPP App prototype, a tool providing individualized risk of spontaneous preterm birth (sPTB), for use in women with symptoms of threatened preterm labor (TPTL), incorporating risk factors, transvaginal ultrasound assessment of cervical length (CL) and cervicovaginal fluid quantitative fetal fibronectin (qfFN) test results.

METHODS

Participants were pregnant women between 23 + 0 and 34 + 6 weeks' gestation with symptoms of TPTL, recruited as part of four prospective cohort studies carried out at 16 UK hospitals between October 2010 and October 2017. The training set comprised all women whose outcomes were known in May 2017 (n = 1032). The validation set comprised women whose outcomes were gathered between June 2017 and March 2018 (n = 506). Parametric survival models were developed for three combinations of predictors: risk factors plus qfFN test results alone, risk factors plus CL alone, and risk factors plus both qfFN and CL. The best models were selected using the Akaike and Bayesian information criteria. The estimated probability of sPTB < 30, < 34 or < 37 weeks' gestation and within 1 or 2 weeks of testing was calculated and receiver-operating-characteristics (ROC) curves were created to demonstrate the diagnostic ability of the prediction models.

RESULTS

Predictive statistics were similar between the training and the validation sets at most outcome time points and for each combination of predictors. Areas under the ROC curves (AUC) demonstrated that all three algorithms had good accuracy for the prediction of sPTB at < 30, < 34 and < 37 weeks' gestation and within 1 and 2 weeks' post-testing in the validation set, particularly the model combining risk factors plus qfFN alone (AUC: 0.96 at < 30 weeks; 0.85 at < 34 weeks; 0.77 at < 37 weeks; 0.91 at < 1 week from testing; and 0.92 at < 2 weeks from testing).

CONCLUSIONS

Validation of the new prediction models suggests that the QUiPP App v.2 can reliably calculate risk of sPTB in women with TPTL. Use of the QUiPP App in practice could lead to better targeting of intervention, while providing reassurance and avoiding unnecessary intervention in women at low risk. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

The Biomarkers for Preterm Birth Study-A prospective observational study comparing the impact of vaginal biomarkers on clinical practice when used in women with symptoms of preterm labor

INTRODUCTION

This study aims to compare the use of qualitative fetal fibronectin, quantitative fetal fibronectin, and placental α-microglobulin-1 in women with symptoms of preterm labor, to evaluate which vaginal biomarker performs the best in clinical practice.

MATERIAL AND METHODS

This prospective observational study included women who presented with symptoms of preterm labor at 24⁺⁰ to 34⁺⁰  weeks of gestation at a large tertiary maternity hospital in Auckland, New Zealand. Women were managed according to hospital guidelines using qualitative fetal fibronectin. Quantitative fetal fibronectin and placental α-microglobulin-1 tests were also taken, with clinicians blinded to the results. Management and delivery outcomes were collected from clinical records. The primary outcome was the rate of antenatal hospital admission. Analysis was performed according to predefined management protocols for each of the tests.

RESULTS

A total of 128 women had all three biomarkers tests taken. Spontaneous preterm birth rates were 7/128 (5.5%) ≤34⁺⁰  weeks and 20/128 (15.6%) <37⁺⁰  weeks of gestation; 5/128 (3.9%) delivered within 7 days of testing. Positive results were recorded in 28 qualitative fetal fibronectin tests, 25 quantitative fetal fibronectin tests with 11 ≥200 ng/mL, and 16 placental α-microglobulin-1 tests. The use of quantitative fetal fibronectin or placental α-microglobulin-1 would have lowered antenatal admission rates: 27/128 (21.1%) for qualitative fetal fibronectin, 11/128 (8.6%) for quantitative fetal fibronectin (admission threshold ≥200 ng/mL), and 15/128 (11.7%) for placental α-microglobulin-1. No additional women with quantitative fetal fibronectin <200 ng/mL delivered within 7 days or missed corticosteroids compared with standard care (qualitative fetal fibronectin); however, an additional 3 cases had a false-negative placental α-microglobulin-1 and clinical care may have been compromised (no antenatal corticosteroids or admission).

CONCLUSIONS

The use of quantitative fetal fibronectin (admission threshold ≥200 ng/mL) has the potential to reduce the rate of antenatal admissions for women with symptoms of preterm labor without compromising use of antenatal interventions that improve outcomes for babies born preterm.

Cervico-vaginal placental α-macroglobulin-1 combined with cervical length for the prediction of preterm birth in women with threatened preterm labor

INTRODUCTION

Preterm birth is a major cause of neonatal morbidity and mortality. There is an urgent need to accurately predict imminent delivery to enable necessary interventions such as tocolytic, glucocorticoid, and magnesium sulfate administration. We aimed to evaluate placental α-macroglobulin-1 as a new diagnostic marker in the prediction of preterm birth.

MATERIAL AND METHODS

We performed a prospective observational trial in women with intact membranes between 24⁺⁰ and 36⁺⁶ weeks of gestation. We included both women with and without threatened preterm labor symptoms. We evaluated the test performance of placental α-macroglobulin-1 measurements in cervicovaginal fluid regarding three different presentation-to-delivery intervals: ≤2, ≤7, ≤14 days. In addition, we calculated placental α-macroglobulin-1 performance in combination with other prognostic factors such as ultrasonographic cervical length measurements.

RESULTS

We included 126 women in the study. We detected high specificity (97%-98%) and negative predictive value (89%-97%) for placental α-macroglobulin-1 at all time intervals. We assessed placental α-macroglobulin-1 in combination with cervical length measurements (≤15 mm) in the sub-group of women presenting with threatened preterm labor symptoms (n = 63) and detected high positive predictive values (100%) for 7- and 14-day presentation-to-delivery intervals.

CONCLUSIONS

Our study provides evidence that placental α-macroglobulin-1 testing in cervicovaginal fluid, in combination with cervical length measurements, accurately predicts preterm birth in women with preterm labor symptoms. This novel test combination may be used clinically to triage women presenting with threatened preterm labor, avoiding overtreatment and unnecessary hospitalizations.

The prediction of preterm delivery: What is new?

Preterm birth, defined as birth occurring prior to 37 weeks gestation, is a serious obstetric problem accounting for 11% of pregnancies worldwide. It is associated with significant neonatal morbidity and mortality. Predictive tests for preterm birth are incredibly important, given the huge personal, economic, and health impacts of preterm birth. They can provide reassurance for women who are unlikely to deliver early, but they are also important for highlighting those women at higher risk of premature delivery so that we can offer prophylactic interventions and help guide antenatal management decisions. Unfortunately, there is unlikely to be a single test for predicting preterm birth, but a combination of tests is likely to improve clinical prediction. This review explores the clinical utility of the currently marketed predictive tests for preterm birth in both singleton and multiple pregnancies, as well as discussing novel predictive tests that may be useful in the future.

Is cervical length evaluated by transvaginal ultrasonography helpful in detecting true preterm labor?

Objective: To investigate whether sonographic cervical markers can identify women in true preterm labor and predict delivery within 7 d and before 34 or 37 gestational weeks.Methods: This was a prospective observational study of women with singleton pregnancies and intact membranes given a diagnosis of preterm labor between 25 and 34 weeks and 6 d of gestation and who underwent transvaginal evaluation of the following characteristics: cervical length (CL), CL zeta score, absence of endocervical glandular echo, presence of cervical funneling, and presence of amniotic fluid sludge. The outcomes of interest were spontaneous delivery within 7 d of preterm labor and spontaneous delivery before 34 or 37 gestational weeks.Results: The inclusion criteria were met by 126 women, 31 (25%) of whom were excluded and 95 were analyzed. The median gestational age at admission was 31.9 weeks. The median CL at preterm labor was 22.3 mm (range: 0-42.8 mm). The delivery occurred within 7 d of presentation in 13 (13.7%) cases. Delivery before 34 weeks occurred in 16 (16.8%) cases and before 37 weeks in 40 (42.1%) cases. Logistic regression analysis showed CL in millimeters was an independent predictor of delivery within 7 d (OR 0.918, 95% CI 0.862-0.978, p = .008). For birth before 34 weeks, the predictor was gestational age at admission (OR 0.683, 95% CI 0.539-0.866, p = .002) and before 37 weeks, the presence of cervical funneling (OR 3.778, 95% CI 1.460-9.773, p = .006). The CL ≤ 15 mm had sensitivity and specificity values of 77 and 77%, respectively, and good accuracy (88%) for prediction of delivery within 7 d.Conclusion: The evaluation of the cervix by transvaginal ultrasound in women in preterm labor predicted delivery within 7 d and helped distinguish between true and false labor. The analysis of CL zeta score was not an independent factor to predict delivery in 7 d.

Acute Tocolysis - a Critical Analysis of Evidence-Based Data

Tocolysis is among the most common obstetric measures. The objective is to prolong the pregnancy by at least 48 hours to complete foetal lung maturation and for the in-utero transfer of the pregnant woman to a perinatal centre. The indication for tocolysis is regular, premature contractions (≥ 4/20 min) and a dynamic shortening of the cervical length/cervical opening between 22 + 0 to 33 + 6 weeks of pregnancy. In this connection, the cervical length measured on ultrasound and the determination of biomarkers in the cervicovaginal secretions can be important decision-making aids. Beta sympathomimetics should no longer be used due to the high rate of severe maternal adverse effects. Given controversial data, magnesium sulphate is no longer recommended for tocolysis in current guidelines. Atosiban is as effective for prolonging pregnancy as beta sympathomimetics and nifedipine, has the lowest rate of maternal adverse effects, but also the highest drug costs. Nifedipine and indomethacin are recommended in international guidelines for acute tocolysis, however there are indications of increased neonatal morbidity following indomethacin. Current problems are, above all, the lack of randomised, controlled comparative and placebo-controlled studies, the data which are controversial to some extent, and the insufficient evidence of tocolytics to significantly improve the neonatal outcome.

Effectiveness and Accuracy of Tests for Preterm Delivery in Symptomatic Women: A Systematic Review

This study systematically reviewed evidence on the effectiveness and accuracy of predictive tests for preterm delivery among symptomatic women. The study included English-language systematic reviews (SRs) on any predictive test for preterm delivery among symptomatic women and primary studies for placental alpha-microglobulin-1. PubMed, Wiley Cochrane Library, the Centre for Reviews and Dissemination Database, the National Guidelines Clearinghouse, and the TRIP database were searched for SRs, PubMed and PubMed Central via the Wiley Cochrane Library were searched for primary studies. One reviewer performed study selection, with input from a second reviewer when needed. One reviewer appraised study quality and extracted: study characteristics (i.e., country, funding source, study design [primary studies] or synthesis method [SRs], study appraisal method [SRs]), population characteristics, index test(s) and cut-off points used, comparator(s) or reference standard(s), and outcomes. A second reviewed a random 10% sample. The authors synthesized the findings narratively. Of 451 unique records, the review included 22 (17 SRs, five primary studies). For effectiveness, there was evidence for use of transvaginal sonographic cervical length assessment (15-25 mm cut point) in reducing incidence of preterm delivery at <37 weeks (relative risk 0.64; 95% CI 0.44-0.94, one SR of three trials; n = 287) but lack of support for cervicovaginal fetal fibronectin. In terms of accuracy, one high-quality study within a best-evidence SR showed that cervical length measurement was useful to predict delivery within 48 hours (LR+ 6.43, 95% CI 5.17-8.00; LR- 0.03, 95% CI 0.00-0.42; n = 510) and 7 days (LR+ 8.61, 95% CI 6.65-11.14; LR- 0.03, 95% CI 0.00-0.18; n = 510). Accuracy of placental alpha-microglobulin-1 testing was not supported for most end points. In conclusion, some evidence supports the effectiveness of cervical length as a predictor of preterm delivery in symptomatic women. Evidence for most tests is limited in quality and quantity.

The fetal fibronectin test: 25 years after its development, what is the evidence regarding its clinical utility? A systematic review and meta-analysis

Background: The identification of women at risk for preterm birth should allow interventions which could improve neonatal outcome. Fetal fibronectin, a glycoprotein which acts normally as glue between decidua and amniotic membranes could be a good marker of impending labour when its concentration in cervicovaginal secretions between 22 and 36 weeks of gestation is ≥50 ng/mL. Many authors worldwide have tested this marker with many different methodologies and clinical settings, but conclusions about its clinical use are mixed. It is time for a comprehensive update through a systematic review and meta-analysis.Methods: We searched PubMed, Cochrane Library, and Embase, supplemented by manual search of bibliographies of known primary and review articles, international conference papers, and contact with experts from 1-1990 to 2-2018. We have selected all type of studies involving fetal fibronectin test accuracy for preterm delivery. Two authors independently extracted data about study characteristics and quality from identified publications. Contingency tables were constructed. Reference standards were preterm delivery before 37, 36, 35, 34, and 32 weeks, within 28, 21, 14, or 7 d and within 48 h. Data were pooled to produce summary likelihood ratios for positive and negative tests results.Results: One hundred and ninety-three primary studies were identified allowing analysis of 53 subgroups. In all settings, none of the summary likelihood ratios were >10 or <0.1, thus indicating moderate prediction, particularly in asymptomatic women and in multiple gestations.Conclusions: The fetal fibronectin test should not be used as a screening test for asymptomatic women. For high-risk asymptomatic women, and especially for women with multiple pregnancies, the performance of the fetal fibronectin test was also too low to be clinically relevant. Consensual use as a diagnostic tool for women with suspected preterm labor, the best use policy probably still depends on local contingencies, future cost-effectiveness analysis, and comparison with other more recent available biochemical markers.

Development of a nomogram for individual preterm birth risk evaluation

OBJECTIVE

This study aimed to develop a new tool for personalised preterm birth risk evaluation in high-risk population.

STUDY DESIGN

813 high-risk asymptomatic pregnant women included in a French multicentric prospective study were analysed. Clinical and paraclinical variables, including screening for bacterial vaginosis with molecular biology, cervical length, have been used to create the nomogram, based on the logistic regression model. The validity was checked by bootstrap. A downloadable calculator was build.

RESULTS

Nine risk factors were included in this model: history of late miscarriage and/or preterm delivery, active smoking, ultrasound cervical length, term of pregnancy at screening, bacterial vaginosis, premature rupture of membranes, daily travel more than 30min. Discrimination and calibration of the nomogram revealed good predictive abilities. The area under the receiver operating characteristic curve was 0.77 (95% CI; 0.72-0.81). The mean absolute error was 0.018, which showed proper calibration. The optimal risk threshold was 23.2% with a sensitivity of 74%, a specificity of 72.7% and a predictive negative value of 90.6%.

CONCLUSION

The nomogram can help to better define individual preterm birth risk in high-risk pregnancies.

Cost-effectiveness of diagnostic tests for threatened preterm labor in singleton pregnancy in France

BACKGROUND

Previous studies have showed that the early diagnosis of threatened preterm labor decreases neonatal morbidity and mortality, avoids maternal morbidity induced by antepartum bed rest and unnecessary treatment, and reduces costs. Although there are many diagnostic tests, none is clearly recommended by international guidelines. The aim of our study was to compare seven diagnostic methods in terms of effectiveness and cost using a decision analysis model in singleton pregnancy presenting threatened preterm labor, between 24 and 34 weeks of gestation.

METHODS

Seven diagnostic strategies based on individual or combined use of the following tests: cervical length, cervical fibronectin test, cervical interleukin test and protein in maternal serum, were compared using a decision analysis model. Effectiveness was expressed in terms of serious adverse neonatal events avoided (neonatal morbidity and mortality) at the hospital discharge. The economic analysis was performed from the health care system perspective. Deterministic and probabilistic analyses were performed to test the robustness of the model.

RESULTS

At 24-34 weeks of gestation, the association of cervical length and qualitative fibronectin was the most efficient strategy dominating all alternatives, reducing the perinatal death or severe neonatal morbidity rate up to 15% and the costs up to 31% according to the gestational age. This result was confirmed by the deterministic sensitivity analyses. The probabilistic analysis showed that the association of cervical length and qualitative fibronectin dominated cervical length < 15 mm in more than 90% of the simulations. The comparison with the other tests revealed more uncertainty.

CONCLUSIONS

A test using cervical length and qualitative fetal fibronectin appears to be the best diagnostic strategy. Decisions regarding its generalization and funding in France in this population of women should take into account the high, lifetime costs induced by prematurity.

Quantitative fetal fibronectin and cervical length in symptomatic women: results from a prospective blinded cohort study. J Matern Fetal Neonatal Med 2018;32:3792-3800. [PMID: 29727248 DOI: 10.1080/14767058.2018.1472227]

Objectives: Our objectives were to determine whether quantitative fetal fibronectin (fFN) and cervical length (CL) screening can be used alone or in combination as prognostic tests to identify symptomatic women at the highest or lowest risk for spontaneous preterm birth (sPTB). Methods: A prospective, blinded cohort study of women presenting with a singleton gestation to our triage unit between 22-33w6d with preterm labor symptoms was performed. Women with ruptured membranes, moderate/severe bleeding, and dilation >2 cm were excluded. The primary outcome was sPTB <37 weeks. We evaluated test characteristics of quantitative fFN and CL assessment, both separately and in combination, considering traditionally reported cut-points (fFN ≥50 and CL <25), as well as cut-points above and below these measures. We found interactions between fFN >50 and CL <25 and sPTB by parity and obstetric history (p < .05) and therefore stratified results. Test characteristics are presented with positive predictive value (PPV) and negative predictive value (NPV). Results: Five hundred eighty women were enrolled and 537 women were available for analysis. Overall sPTB rate was 11.1%. Among nulliparous women, increasing levels of fFN were associated with increasing risk of sPTB, with PPV going from 26.5% at ≥20 ng/mL to 44.4% at ≥200 ng/mL. A cut-point of 20 ng/mL had higher sensitivity (69.2%) and higher NPV (96.8%) and therefore identified a "low-risk" group. fFN was not informative for multiparous women regardless of prior obstetrical history or quantitative level chosen. For all women, a shorter CL was associated with an increased sPTB risk. Among nulliparas and multiparas without a prior sPTB, a CL <20 mm optimized test characteristics (PPV 25 and 20%, NPV 95.5, and 92.7%, respectively). For multiparas with a prior sPTB, CL <25 mm was more useful. Using fFN and CL in combination for nulliparas did not improve test characteristics over using the individual fFN (p = .74) and CL (p = .31) components separately. Conclusions: This study identifies the importance of stratifying by parity and obstetrical history when using screening modalities for risk assessment in symptomatic women. For nulliparous women, either quantitative fFN or cervical length assessment can be utilized, depending on resources available, but a lower cut-point of 20 ng/mL should be used for quantitative fFN. For multiparous women, fFN is not useful and cervical length assessment should be the main screening tool utilized when there is clinical uncertainty. Regardless of parity, the PPV of fFN and CL is low and therefore the greatest clinical utility remains in its NPV.

Cost-effectiveness of diagnostic testing strategies including cervical-length measurement and fibronectin testing in women with symptoms of preterm labor

OBJECTIVE

To evaluate the cost-effectiveness of combining cervical-length (CL) measurement and fetal fibronectin (fFN) testing in women with symptoms of preterm labor between 24 and 34 weeks' gestation.

METHODS

This was a model-based cost-effectiveness analysis evaluating seven test-treatment strategies based on CL measurement and/or fFN testing in women with symptoms of preterm labor from a societal perspective, in which neonatal outcomes and costs were weighted. Estimates of disease prevalence, test accuracy and costs were based on two recently performed nationwide cohort studies in The Netherlands.

RESULTS

Strategies using fFN testing and CL measurement separately to predict preterm delivery are associated with higher costs and incidence of adverse neonatal outcomes compared with strategies that combine both tests. Additional fFN testing when CL is 15-30 mm was considered cost effective, leading to a cost saving of €3919 per woman when compared with a treat-all strategy, with a small deterioration in neonatal health outcomes, namely one additional perinatal death and 21 adverse outcomes per 10 000 women with signs of preterm labor (incremental cost-effectiveness ratios €39 million and €1.9 million, respectively). Implementing this strategy in The Netherlands, a country with about 180 000 deliveries annually, could lead to an annual cost saving of between €2.4 million and €7.6 million, with only a small deterioration in neonatal health outcomes.

CONCLUSION

In women with symptoms of preterm labor at 24-34 weeks' gestation, performing additional fFN testing when CL is between 15 and 30 mm is a viable and cost-saving strategy. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Study protocol: quantitative fibronectin to help decision-making in women with symptoms of preterm labour (QUIDS) part 2, UK Prospective Cohort Study

INTRODUCTION

The aim of the QUIDS study is to develop a decision support tool for the management of women with symptoms and signs of preterm labour, based on a validated prognostic model using quantitative fetal fibronectin (fFN) concentration, in combination with clinical risk factors.

METHODS AND ANALYSIS

The study will evaluate the Rapid fFN 10Q System (Hologic, Marlborough, Massachusetts, USA) which quantifies fFN in a vaginal swab. In QUIDS part 2, we will perform a prospective cohort study in at least eight UK consultant-led maternity units, in women with symptoms of preterm labour at 22⁺⁰ to 34⁺⁶ weeks gestation to externally validate a prognostic model developed in QUIDS part 1. The effects of quantitative fFN on anxiety will be assessed, and acceptability of the test and prognostic model will be evaluated in a subgroup of women and clinicians (n=30). The sample size is 1600 women (with estimated 96-192 events of preterm delivery within 7 days of testing). Clinicians will be informed of the qualitative fFN result (positive/negative) but be blinded to quantitative fFN result. Research midwives will collect outcome data from the maternal and neonatal clinical records. The final validated prognostic model will be presented as a mobile or web-based application.

ETHICS AND DISSEMINATION

The study is funded by the National Institute of Healthcare Research Health Technology Assessment (HTA 14/32/01). It has been approved by the West of Scotland Research Ethics Committee (16/WS/0068).

VERSION

Protocol V.2, Date 1 November 2016.

TRIAL REGISTRATION NUMBER

ISRCTN 41598423andCPMS: 31277.

Efficacy of serum procalcitonin to predict spontaneous preterm birth in women with threatened preterm labour: a prospective observational study

Background

A hypothesis of preterm parturition is that the pathogenesis of spontaneous preterm birth (sPTB) may be associated with an inflammatory process. Based on this theory, we have hypothesized that an inflammatory biomarker, procalcitonin (PCT), may be a good predictive marker of sPTB at the admission for threatened preterm labour (TPL). The present study was aimed to investigate the association between serum PCT and sPTB in women with TPL and to evaluate whether PCT levels may predict sPTB in women with TPL within 7 or 14 days.

Methods

In a prospective observational laboratory-based study, women with singleton pregnancies, TPL between 24 and 36 weeks and intact membranes, were enrolled between January 2014 and June 2016. Participants received routine medical management of TPL (tocolysis with atosiban, antenatal corticosteroids, and biological tests at admission (C-reactive protein, white blood cell count, and PCT measured on electrochemiluminescence immunoassay)). The primary endpoint was sPTB before 37 weeks of gestation. The value of serum PCT levels to predict sPTB within 7 or 14 days were evaluated using receiver-operating curves (ROC) analysis.

Results

A total of 124 women were included in our study. PCT levels did not statistically differ between women with sPTB (n = 30, 24.2%) and controls (n = 94) (median in ng/mL [interquartile range]: 0.043 [0.02–0.07] compared to 0.042 [0.02–0.13], respectively; P = 0.56). PCT levels did not also statistically differ between women with sPTB within 7 days (n = 7, 5.6%) or 14 days (n = 12, 9.7%) after testing and controls. Moreover, subgroup analysis revealed no difference among PCT levels at admission between 24 and 28 weeks, between 28 and 32 weeks and over 32 weeks, and controls. On the basis of the receiver-operating characteristic curve, the highest sensitivity and specificity corresponded to a PCT concentration of 0.038 ng/mL, with poor predictive values for sPTB within 7 or 14 days.

Conclusion

Serum PCT was not relevant to predict sPTB within 7 or 14 days in women admitted with TPL between 24 and 36 weeks, and thus it is not a suitable biological marker to confirm the hypothesis of an inflammatory process associated with preterm parturition.

Trial registration

Clinicaltrials.gov (NCT01977079), Registered 24 October 2013.

Accuracy of fetal fibronectin for the prediction of preterm birth in symptomatic twin pregnancies: a pilot study

Our goal was to evaluate the performance of fetal fibronectin (fFN) test alone or combined with cervical length (CL), to predict spontaneous preterm birth (PTB) in symptomatic twin pregnancies. We carry out a short pilot study including all uncomplicated diamniotic twin pregnancies with symptoms of preterm labor (PTL) and intact membranes at 24-33 weeks + 6 days of gestation. Studied outcome were spontaneous delivery within 7 and 14 days of testing and spontaneous PTB at <34 and <37 weeks of gestation. Among 40 women, fFN test was positive in 3 of them (7.5%). Regardless of the outcome studied CL did not significantly predict PTB. Performance of fFN was sensitivity (66.7%), specificity (97.2%), positive predictive value (66.7%), negative predictive value (97.2%), positive likelihood ratio (LR) (24.0), and negative LR (0.3) to predict spontaneous PTB within 7 days (p = 0.01). Thus, 66.1% of patients with a positive fFN test would deliver within 7 days versus 2.4% if negative testing; starting with a pre-test probability of 7.5%. Combining CL and fFN did not enable to increase enough positive LR or decrease significantly negative LR. In conclusion, fFN test alone might have a better ability to detect spontaneous delivery within 7 days among symptomatic twin pregnancies.

Maintaining and repeating tocolysis: A reflection on evidence

It is inherent to human logic that both doctors and patients want to suppress uterine contractions when a woman presents in threatened preterm labor. Tocolysis is widely applied in women with threatened preterm labor with a variety of drugs. According to literature, tocolysis is indicated to enable transfer to a tertiary center as well as to ensure the administration of corticosteroids for fetal maturation. There is international discrepancy in the content and the implementation of guidelines on preterm labor. Tocolysis is often maintained or repeated. Nevertheless, the benefit of prolonging pregnancy has not yet been proven, and it is not impossible that prolongation of the pregnancy in a potential hostile environment could harm the fetus. Here we reflect on the use of tocolysis, focusing on maintenance and repeated tocolysis, and compare international guidelines and practices to available evidence. Finally, we propose strategies to improve the evaluation and use of tocolytics, with potential implications for future research.

Hospital admission for hyperemesis gravidarum in women at increased risk of spontaneous preterm birth

BACKGROUND

Progesterone administration prevents spontaneous preterm birth (sPTB) in women at increased risk. Progesterone concentration is lower in women with subsequent sPTB. Conversely, high concentrations of progesterone are implicated in the pathogenesis of hyperemesis gravidarum (HG). We hypothesized that women at increased risk of sPTB or spontaneous late miscarriage would be less likely to have a diagnosis of HG. To explore this hypothesis, we compared the incidence of HG in women at increased risk of sPTB and women with no identifiable risk factors.

METHODS

Women at increased risk of sPTB were identified from a specialist Preterm Birth Clinic (PTBC) database where criteria for PTBC attendance are previous cervical surgery, previous sPTB <34 weeks, previous spontaneous late miscarriage, incidental sonographic cervical shortening, and uterine anomaly. Hospital antenatal booking and coding records for the same time period were examined to identify HG admissions. Women with multiple gestations, trophoblastic disease, or pre-existing abnormal thyroid function were excluded. The incidence of HG among PTBC (n=394) and non-PTBC attendees (n=4762) was calculated.

RESULTS

The incidence of HG was lower in women at increased risk of sPTB (1.52%, n=6) compared with women with no identifiable risk factor for sPTB (3.33%, n=159; P=.049).

CONCLUSION

Hospital admission for HG is reduced in women with risk factors for sPTB compared with those without risk factors. Exploration of the pathogenesis of HG may improve understanding of the mechanisms underlying sPTB.

Utilization of fetal fibronectin testing and pregnancy outcomes among women with symptoms of preterm labor

Objectives

To identify pregnant health plan members triaged through the emergency department (ED), including labor and delivery (ELD) units, with symptoms of preterm labor (PTL), and evaluate the use of fetal fibronectin (fFN) testing; and to calculate the rate of hospitalization and timing of delivery in relation to the ED visit.

Methods

Retrospective cohort study using Medical Outcomes Research for Effectiveness and Economics Registry^®, a national multipayer claims database. A cohort of pregnant women evaluated in an ELD with a diagnosis of PTL from June 2012 through November 2015 was identified. The proportion of women with PTL who received fFN testing was calculated.

Results

A total of 23,062 patients met the criteria for inclusion in the study. The rate of fFN testing prior to delivery was 12.0%. Of the 23,062 patients included in the analysis, 75.9% were discharged home. Of those who were discharged from the emergency room, one in five went on to deliver within 3 days and almost 96% of this group was not screened for the presence of fFN. Of the remaining 24.1% of patients admitted to the hospital, 91.3% delivered during their stay. In a sensitivity analysis, the percentage of women who delivered within 3 days of the ELD encounter was lower for women who received fFN testing only (6.6%) versus those who had a history of transvaginal ultrasound (TVUS) only (21.6%). Furthermore, the rate of delivery within 3 days was lowest among patients who had both fFN testing and TVUS (4.7%).

Conclusion

The utilization of fFN testing is 12%. The majority of pregnant patients triaged through the ELD with symptomatic PTL do not receive an fFN test. As part of PTL evaluation, fFN testing may identify women at increased risk for preterm delivery and help determine appropriate patient management.

The cytokine network in women with an asymptomatic short cervix and the risk of preterm delivery

PROBLEM

To characterize the amniotic fluid (AF) inflammatory-related protein (IRP) network in patients with a sonographic short cervix (SCx) and to determine its relation to early preterm delivery (ePTD).

METHOD OF STUDY

A retrospective cohort study included women with a SCx (≤25 mm; n=223) who had amniocentesis and were classified according to gestational age (GA) at diagnosis and delivery (ePTD <32 weeks of gestation).

RESULTS

(i) In women with a SCx ≤ 22 1/7 weeks, the concentration of most IRPs increased as the cervix shortened; those with ePTD had a higher rate of increase in MIP-1α, MCP-1, and IL-6 concentrations than those delivering later; and (ii) the concentration of most IRPs and the correlation between several IRP pairs were higher in the ePTD group than for those delivering later.

CONCLUSION

Women with a SCx at 16-22 1/7 weeks have a unique AF cytokine network that correlates with cervical length at diagnosis and GA at delivery. This network may aid in predicting ePTD.

Spontaneous Preterm Birth Is Associated with Differential Expression of Vaginal Metabolites by Lactobacilli-Dominated Microflora

A major challenge in preventing preterm birth (PTB) is identifying women at greatest risk. This pilot study prospectively examined the differences in vaginal microbiota and metabolite profiles of women who delivered prematurely compared to their term counterparts in a cohort of asymptomatic (studied at 20–22, n = 80; and 26–28 weeks, n = 41) and symptomatic women (studied at 24–36 weeks, n = 37). Using 16S rRNA sequencing, the vaginal microbiota from cervicovaginal fluid samples was characterized into five Community State Types (CST) dominated by Lactobacillus spp.: CSTI (Lactobacillus crispatus), CSTII (Lactobacillus gasseri), CSTIII (Lactobacillus iners), CSTV (Lactobacillus jensenii); and mixed anaerobes—CSTIV. This was then related to the vaginal metabolite profile and pH determined by ¹H-Nuclear Magnetic Resonance spectroscopy and pH indicator paper, respectively. At 20–22 weeks, the term-delivered women (TDW) indicated a proportion of CSTI-dominated microbiota >2-fold higher compared to the preterm-delivered women (PTDW) (40.3 vs. 16.7%, P = 0.0002), and a slightly higher proportion at 26–28 weeks (20.7 vs. 16.7%, P = 0.03). CSTV was >2-fold higher in the PTDW compared to TDW at 20–22 (22.2 vs. 9.7%, P = 0.0002) and 26–28 weeks (25.0 vs. 10.3%, P = 0.03). Furthermore, at 26–28 weeks no PTDW had a CSTII-dominated microbiome, in contrast to 28% of TDW (P < 0.0001). CSTI-dominated samples showed higher lactate levels than CSTV at 20–22 weeks (P < 0.01), and 26–28 weeks (P < 0.05), while CSTII-dominated samples indicated raised succinate levels over CSTV at 26–28 weeks (P < 0.05). These were supported by Principal coordinates analysis, which revealed strong clustering of metabolites according to CST. In addition, the CSTI-dominated samples had an average pH of 3.8, which was lower than those of CSTII—4.4, and CSTV—4.2 (P < 0.05). Elevated vaginal lactate and succinate were associated with predominance of CSTI and II over CSTV in women who delivered at term compared with their preterm counterparts. This suggests that L. jensenii-dominance and decreased lactate and/or succinate could increase the risk of PTB, while L. crispatus/gasseri may confer some protection against inflammation-associated PTB and highlight the need for further study in this area.

Placental inflammation and its relationship to cervicovaginal fetal fibronectin in preterm birth

OBJECTIVE

Late miscarriage and preterm birth are frequently thought to be associated with inflammation and infection, although in most cases the underlying cause of early delivery remains unknown. The placenta is the organ that links mother and fetus during pregnancy, and postnatal examination may provide useful information about pathophysiology. The relationship between placental pathological lesions and predictive markers of early delivery has not been explored. We sought to characterize preterm deliveries according to placental pathology and relate these to the performance of reliable predictive markers, fetal fibronectin and cervical length.

STUDY DESIGN

This is a retrospective subanalysis from a larger prospective cohort study on sonographic cervical length, quantitative fetal fibronectin and risk of spontaneous preterm birth. Our cohort was comprised of high-risk asymptomatic women attending the Prematurity Surveillance Clinic at St Thomas' Hospital between 2002 and 2015, who went on to have a late miscarriage or preterm delivery (16-36⁺⁶ weeks') and who had available placental histology. The placental pathology of these preterm deliveries was characterized according to the lesions identified, and categorized (according to the Redman classification) into inflammatory (e.g. chorioamnionitis) or non-inflammatory (histologically normal or vascular lesions indicating e.g. malperfusion). We sought to relate placental findings to the performance of reliable predictive markers, in women who delivered early. Standard clinical cut offs for cervical length (<25mm) and fetal fibronectin (>50ng/mL) were used to identify the proportion of preterm births that were accurately predicted by the tests or who showed a false negative result, in relation to their placental histology findings. Binomial logistic regression was carried out to evaluate the relationship between placental inflammation, quantitative fFN and cervical length as continuous variables.

RESULTS

105 women who had a late miscarriage or preterm delivery (16-36⁺⁶ weeks') and available placenta pathology were identified. 66% (42/64) of those with inflammatory placental pathology had a positive fetal fibronectin swab result compared to 15% (6/41) of those with non-inflammatory placental pathology (chi-squared 25.9, 95% CI 31.5 to 65.6, p<0.0001). A logistic regression model subanalysis of women in whom both CL and quantitative fFN results were available (n=66) revealed a highly statistically significant relationship with inflammatory placental lesions (p=0.003 and p=0.001 respectively). Placental inflammation was found to be associated with both increasing levels of fFN and a shortening cervix.

CONCLUSION

There is a significant association between a positive fetal fibronectin result and underlying inflammatory pathology of the placenta, even more so than the recognized relationship with short cervical length. Infective morbidity may be increased in women and neonates with positive fetal fibronectin who deliver preterm.

Influence of transvaginal ultrasound examination on quantitative vaginal fibronectin measurements: a prospective evaluation study

OBJECTIVE

The most important parameter in prediction of preterm birth is the cervical length measured by transvaginal ultrasound. In cases with mid-range cervical length (10-30 mm), prediction of preterm birth is difficult. In these cases, testing for cervicovaginal fluid fetal fibronectin (fFN) can improve prediction. However, it is unclear whether transvaginal ultrasound itself influences the fFN result. The purpose of this study was to evaluate this issue independent of gestational age and cervical length.

METHODS

A prospective evaluation study with 96 cases of pregnant women at 20-41 weeks of gestation was conducted in a tertiary perinatal center. A comparison of cervicovaginal fFN samples before and immediately after transvaginal ultrasound was performed. Fetal fibronectin was measured using the Hologic Rapid fFN 10Q system. It was analyzed quantitatively and qualitatively with ≥50 ng/mL as threshold for "positive". Changes in fFN values following transvaginal ultrasound were measured.

RESULTS

Ninety-six percent (69/72) of women with a fFN concentration of <26 ng/mL before ultrasound had a corresponding fFN value <26 ng/mL after ultrasound. Ninety-three percent (13/14) of women with a fFN concentration of ≥100 ng/mL before ultrasound had a corresponding fFN value ≥100 ng/mL after ultrasound. In 80% (4/5) of women with a positive fFN sample but with a value <100 ng/mL, it turned negative (<50 ng/mL) after ultrasound. For fFN concentrations ≥100 ng/mL, there are high random fluctuations in the measurement results.

CONCLUSIONS

Fetal fibronectin values of <26 ng/mL (for "negative") and ≥100 ng/mL (for "positive") from samples taken after ultrasound provide the same qualitative information as when sampled before ultrasound. For the correct interpretation however, quantitative analysis is necessary.

Review: Eicosanoids in preterm labor and delivery: Potential roles of exosomes in eicosanoid functions

Preterm delivery is a major obstetric health problem contributing to poor neonatal outcome including low birth weight, respiratory distress syndrome, gastrointestinal, immunologic, central nervous system, hearing, and vision problems. Worldwide, approximately 15 million babies are born prematurely each year. The critical question which remains is how to identify women destined to deliver preterm from those who will achieve a term delivery. Prostaglandins, in all mammals, are important in the parturient process. Increased intrauterine prostaglandin production is associated with labor and in fact prostaglandin E₂ (PGE₂) or analogs are widely used clinically for cervical ripening and labor induction. Measurements of circulating eicosanoids have been problematic because of the rapid and major clearance by the lungs and then kidneys resulting in very low concentrations in plasma. Moreover, since eicosanoids are produced by all mammalian tissues, the sources of the measured eicosanoids are unknown. Our understanding of how cells communicate has undergone a paradigm shift with the recognition of the role of exosomes in intercellular signaling. Recent publications have identified enzymes and products of arachidonic acid metabolism (eicosanoids) within exosomes. This review will explore the potential roles of exosomes in eicosanoid functions that are critical in preterm labor and delivery.

The predictive value of quantitative fibronectin testing in combination with cervical length measurement in symptomatic women

BACKGROUND

The combination of the qualitative fetal fibronectin test and cervical length measurement has a high negative predictive value for preterm birth within 7 days; however, positive prediction is poor. A new bedside quantitative fetal fibronectin test showed potential additional value over the conventional qualitative test, but there is limited evidence on the combination with cervical length measurement.

OBJECTIVE

The purpose of this study was to compare quantitative fetal fibronectin and qualitative fetal fibronectin testing in the prediction of spontaneous preterm birth within 7 days in symptomatic women who undergo cervical length measurement.

STUDY DESIGN

We performed a European multicenter cohort study in 10 perinatal centers in 5 countries. Women between 24 and 34 weeks of gestation with signs of active labor and intact membranes underwent quantitative fibronectin testing and cervical length measurement. We assessed the risk of preterm birth within 7 days in predefined strata based on fibronectin concentration and cervical length.

RESULTS

Of 455 women who were included in the study, 48 women (11%) delivered within 7 days. A combination of cervical length and qualitative fibronectin resulted in the identification of 246 women who were at low risk: 164 women with a cervix between 15 and 30 mm and a negative fibronectin test (<50 ng/mL; preterm birth rate, 2%) and 82 women with a cervix at >30 mm (preterm birth rate, 2%). Use of quantitative fibronectin alone resulted in a predicted risk of preterm birth within 7 days that ranged from 2% in the group with the lowest fibronectin level (<10 ng/mL) to 38% in the group with the highest fibronectin level (>500 ng/mL), with similar accuracy as that of the combination of cervical length and qualitative fibronectin. Combining cervical length and quantitative fibronectin resulted in the identification of an additional 19 women at low risk (preterm birth rate, 5%), using a threshold of 10 ng/mL in women with a cervix at <15 mm, and 6 women at high risk (preterm birth rate, 33%) using a threshold of >500 ng/mL in women with a cervix at >30 mm.

CONCLUSION

In women with threatened preterm birth, quantitative fibronectin testing alone performs equal to the combination of cervical length and qualitative fibronectin. Possibly, the combination of quantitative fibronectin testing and cervical length increases this predictive capacity. Cost-effectiveness analysis and the availability of these tests in a local setting should determine the final choice.

Cervicovaginal Fluid Acetate: A Metabolite Marker of Preterm Birth in Symptomatic Pregnant Women

Changes in vaginal microbiota that is associated with preterm birth (PTB) leave specific metabolite fingerprints that can be detected in the cervicovaginal fluid (CVF) using metabolomics techniques. In this study, we characterize and validate the CVF metabolite profile of pregnant women presenting with symptoms of threatened preterm labor (PTL) by both ¹H-nuclear magnetic resonance spectroscopy (NMR) and enzyme-based spectrophotometry. We also determine their predictive capacity for PTB, singly, and in combination, with current clinical screening tools – cervicovaginal fetal fibronectin (FFN) and ultrasound cervical length (CL). CVF was obtained by high-vaginal swabs from 82 pregnant women with intact fetal membranes presenting between 24 and 36 weeks gestation with symptoms of threatened, but not established, PTL. Dissolved CVF samples were scanned with a 400 MHz NMR spectrometer. Acetate and other metabolites were identified in the NMR spectrum, integrated for peak area, and normalized to the total spectrum integral. To confirm and validate our observations, acetate concentrations (AceConc) were also determined from a randomly-selected subset of the same samples (n = 57), by spectrophotometric absorption of NADH using an acetic acid assay kit. CVF FFN level, transvaginal ultrasound CL, and vaginal pH were also ascertained. Acetate normalized integral and AceConc were significantly higher in the women who delivered preterm compared to their term counterparts (P = 0.002 and P = 0.006, respectively). The ¹H-NMR-derived acetate integrals were strongly correlated with the AceConc estimated by spectrophotometry (r = 0.69; P < 0.0001). Both methods were equally predictive of PTB <37 weeks (acetate integral: AUC = 0.75, 95% CI = 0.60–0.91; AceConc: AUC = 0.74, 95% CI = 0.57–0.90, optimal predictive cutoff of >0.53 g/l), and of delivery within 2 weeks of the index assessment (acetate integral: AUC = 0.77, 95% CI = 0.58–0.96; AceConc: AUC = 0.68, 95% CI = 0.5–0.9). The predictive accuracy of CVF acetate was similar to CL and FFN. The combination of CVF acetate, FFN, and ultrasound CL in a binary logistic regression model improved the prediction of PTB compared to the three markers individually, but CVF acetate offered no predictive improvement over ultrasound CL combined with CVF FFN. Elevated CVF acetate in women with symptoms of PTL appears predictive of preterm delivery, as well as delivery within 2 weeks of presentation. An assay of acetate in CVF may prove of clinical utility for predicting PTB.

Prediction of preterm delivery by second trimester inflammatory biomarkers in the amniotic fluid

OBJECTIVE

To search for a correlation between mid-pregnancy altered levels of inflammatory markers and preterm delivery.

METHODS

A prospective cohort series included 39 patients undergoing amniocentesis one additional milliliter of amniotic fluid (AF) was stored for later dosage of interleukin-6 (Il-6), matrix metalloproteinase-9 (MMP-9), glucose and C-reactive protein (CRP). Maternal serum CRP and glucose levels were also obtained. Exclusion criteria were multiple pregnancies, chorioamnionitis, group B streptococcus colonization, bacterial vaginosis and cases with proven aneuploidy. We searched for correlation between AF and plasmatic markers and also for a difference between patients with term and preterm delivery.

RESULTS

33 participants were eligible and one third had preterm delivery. Levels of the plasmatic biomarkers did not correlate with the AF biomarkers except for plasmatic glucose and AF IL-6 levels (r=0.350; p=0.016). The levels of all AF biomarkers did not differ significantly between the pre-term and the term groups (p>0.05). The optimal screening cutoffs for identifying pregnancies at risk were different than the ones initially indicated.

CONCLUSION

Mid-pregnancy amniotic fluid biomarker levels do not correlate with preterm delivery. Plasma CRP is not correlated with these markers. Cutoff levels suggested are sparse and heterogeneous. Larger studies are needed before advising routine measurement of these markers.

Correlation Between Cervical Lengths Measured by Transabdominal and Transvaginal Sonography for Predicting Preterm Birth

OBJECTIVES

Cervical length assessment is important for predicting preterm birth. Cervical length measurement using transabdominal sonography is more comfortable for the patient but has more limitations than transvaginal sonography. Our aim was to determine whether transabdominal sonography could identify those women who should undergo transvaginal sonography for prediction of preterm birth.

METHODS

In this prospective study, women underwent cervical length measurements by transabdominal and transvaginal sonography between 20 and 29 gestational weeks and were followed until delivery. We assessed whether short cervical lengths on transabdominal sonography could predict short cervical lengths on transvaginal sonography and whether these measurements could predict preterm births (<34 gestational weeks).

RESULTS

The mean cervical lengths were not significantly different between the techniques (mean ± SD, 3.78 ± 0.82 and 3.82 ± 0.77 cm on transabdominal and transvaginal sonography, respectively; P = .09). The sensitivity of short cervical lengths (<2 cm) on transabdominal sonography for prediction of short cervical lengths on transvaginal sonography was 100%. The sensitivity, specificity, positive predictive value, negative predictive value, and relative risk of short cervical lengths (<2 cm) for predicting preterm birth were 21.4%, 98.68%, 50.00%, 95.32%, and 13.22 when using transabdominal sonography and 28.57%, 94.94%, 66.6%, 95.74%, and 17.78 when using transvaginal sonography, respectively. In an analysis that included cases with transabdominal sonography, the sensitivity of short cervical lengths for predicting preterm birth was increased.

CONCLUSIONS

Women whose cervical lengths are measurable and long on transabdominal sonography may not need transvaginal sonography. Women whose cervical lengths are unmeasurable or short (<2 or <2.5 cm) on transabdominal sonography should undergo transvaginal sonography to measure cervical lengths for prediction of preterm birth.

The impact of fetal gender and ethnicity on the risk of spontaneous preterm delivery in women with symptoms of preterm labor

OBJECTIVE

The objective of this study is to evaluate the relation among fetal gender, ethnicity, and preterm labor (PTL) and preterm delivery (PTD).

METHODS

A secondary analysis was performed of a prospective cohort study including women with symptoms of PTL between 24 and 34 weeks. The proportion of women carrying a male or female fetus at the onset of PTL was calculated. Gestational age at delivery and risk of PTD of both fetal genders was compared and interaction of fetal gender and maternal ethnicity on the risk of PTD was evaluated.

RESULTS

Of the 594 included women, 327 (55%) carried a male fetus. Median gestational age at delivery in women pregnant with a male fetus was 37 5/7 (IQR 34 4/7-39 1/7) weeks compared with 38 1/7 (IQR 36 0/7-39 5/7) weeks in women pregnant with a female fetus (p = 0.032). The risk of PTD did not differ significantly. In Caucasians, we did find an increased risk of PTD before 37 weeks in women pregnant with a male fetus (OR 1.9 (95% CI 1.2-3.0)).

CONCLUSIONS

The majority of women with PTL are pregnant with a male fetus and these women deliver slightly earlier. Race seems to affect this disparity.

Efficacy of midtrimester short cervix interventions is conditional on intraamniotic inflammation

BACKGROUND

Midtrimester ultrasound is a valuable method for identifying asymptomatic women at risk for spontaneous preterm delivery (PTD). However, response to various treatments (cerclage, progestogen) has been variable in the clinical setting. It remains unclear how other biomarkers may be used to guide intervention strategies.

OBJECTIVE

We applied an amniotic fluid inflammatory scoring system to determine if the degree of inflammation is associated with intervention efficacy in patients with midtrimester short cervix.

STUDY DESIGN

Women carrying a singleton fetus between 16-24 weeks' gestation with a short cervix (≤25 mm) on transvaginal ultrasound underwent amniocentesis and were assigned to McDonald cerclage, no cerclage, or weekly 17-alpha hydroxyprogesterone caproate (17OHP-C). Our previously described inflammatory risk score (comprised of 14 inflammatory markers) was used to classify patients as high (score ≥8) or low (score <8) risk for inflammation. Gestational age at delivery was compared for each intervention and risk score status. Risk of delivering as a function of the remaining gestation was evaluated using modified Cox proportional hazards models with incorporation of methods to account for both left and right truncation bias.

RESULTS

Ninety patients were included: 24 were in the nonintervention control group, 51 received cerclage, and 15 received 17OHP-C. Inflammation status at time of sampling influenced the efficacy of the treatment (P < .001). Compared to the nonintervention control group, in patients with low inflammation (score < 8), both cerclage (adjusted hazard ratio [HR], 2.86; 95% confidence interval [CI], 1.28-6.37) and 17OHP-C (HR, 3.11; 95% CI, 1.04-9.30) were associated with increased hazard of PTD. In contrast, in patients with high inflammation (score ≥8) both cerclage (HR, 0.22; 95% CI, 0.08-0.65) and 17OHP-C (HR, 0.20; 95% CI, 0.05-0.81) were associated with lower hazard of delivering preterm.

CONCLUSION

Cerclage placement or administration of 17OHP-C therapy for midtrimester short cervix for PTD prevention appears beneficial only in the subset of patients with high inflammation. Knowledge of the amniotic fluid inflammatory status may aid in guiding the appropriate therapy for women presenting with midtrimester short cervix who are at increased risk of PTD.