Universal cervical length screening: implementation and outcomes

Second trimester cervical length screening, in a low-risk European population

PURPOSE

The aim of this work is to assess cervical length (CL) distribution in a low-risk population in order to evaluate the applicability of a possible universal CL screening in the second trimester, aimed at preventing preterm birth (PTB).

METHODS

In a multicentric, prospective cohort study, singleton pregnant women attending second trimester anatomy scan between 18 + 0 to 22 + 6 weeks of gestation were eligible. Teenage pregnancy and women with previous PTB were excluded. The recruitment occurred from February 2020 to December 2022. TVU CL was measured by expert sonographers, in 12 National Health Service (NHS) care clinics of Modena and Parma districts (Emilia-Romagna Region, Italy). Internal quality check of images was performed. Personal and obstetric history, as well as gestational age were collected. Primary outcomes were to define CL curves and the incidence of CL ≤25 mm in low-risk pregnant women Secondary outcomes were the incidences of PTB <37, <34, and <32 weeks.

RESULTS

Among 3226 screened women, mean and median CL were 40.8 and 40 mm, respectively. The 10th centile was equal to 33 mm while 25 mm represented the 2nd centile of the distribution. The incidence of CL ≤25 mm (short cervix) was 1.25%. Among those women, 7.5% were shorter than 150 cm, opposed to 2.1% in the normal CL group (p = .02); in addition there were more nullipara, women ≥ 40 and smokers (p = .03). Women with short cervix were at higher risk of PTB (23.6 vs 4.3%; RR: 4.6, 95%CI 2.49-8.48). At multivariate analysis, both CL ≤ 25 mm (RR: 5.51, 95%CI: 2.45-12.3) and stature ≤150 cm (RR: 2.54, 95%CI: 1.11-5.79) resulted independent predictors for PTB, once adjusted for other risk factors (fibroids, cervical surgery, obesity, low education, older age, smoking habit).

CONCLUSION

Although our study confirmed that women with short cervix are more likely to deliver preterm, the low incidence of such risk factor means that most of the preterm births occurred among women with normal cervical length. Thus, in a low-risk Italian population, ineffectiveness of universal screening is forecast.

Evaluation of a two-tier preterm birth prevention service in a tertiary hospital in the United Kingdom: a retrospective cohort study

BACKGROUND

Preterm birth is the most important cause of neonatal morbidity and mortality. Clinical guidelines recommend assessment of risk of preterm birth and implementation of interventions to reduce preterm birth risk through dedicated preterm birth clinics. We hypothesized that a two-tier preterm birth clinic pathway can safely manage women at the highest risk of preterm birth while reducing intervention for women at moderate risk of preterm birth. We aimed to test this hypothesis by evaluating risk factors, management, and outcomes of women attending a two-tier preterm birth prevention service.

METHODS

We conducted a retrospective cohort study of women who gave birth between January and June 2021 at a tertiary hospital in Oxford, UK. We included two cohorts: women attending a Cervical Screening Clinic and women attending a Preterm Birth Clinic, and we also reviewed all cases of births before 34 weeks over that time period. At the initial midwife appointment at 8-10 weeks' gestation, risk factors for preterm birth were assessed. Pregnant women with moderate risk factors (previous preterm birth at 32+ 0 - 33+ 6 weeks, previous preterm prelabour rupture of membranes (PPROM) at 32+ 0 - 33+ 6 weeks, previous LLETZ / cone biopsy, known abnormal uterus, previous caesarean section at 10 cm dilatation, and multiple pregnancy) were referred to the Cervical Screening Clinic for a cervical length scan by a sonographer. Pregnant women with major risk factors (previous preterm birth at 16+ 0 - 31+ 6 weeks, previous PPROM at less than 32+ 0 weeks, radical trachelectomy, previous cervical cerclage) as well as those with a cervix < 25 mm at any scan were referred to the Preterm Birth Clinic for a cervical length scan and counselling by a specialist obstetrician. Detailed information on risk factors, management, and perinatal outcomes were collected from case notes and analysed.

RESULTS

189 women attended the Cervical Screening Clinic: 79.1% had a moderate risk factor for preterm birth, 100% had a cervical length scan, 7% had a short cervix and 4.2% received an intervention. All 196 infants were live born, with overall preterm birth rates of 14.8% at < 37 weeks, 3.1% at < 32 weeks, and 0% at < 28 weeks. The spontaneous live preterm birth rates were 9.7% at < 37 weeks, 2.6% at < 32 weeks and 0% at < 28 weeks. 79 women attended the Preterm Birth Clinic: 87.3% had a major risk factor for preterm birth, 100% had ≥ 1 cervical length scan, 41.3% had a short cervix, 78.1% received vaginal progesterone, and 39% had a cervical cerclage. Overall preterm birth rates were 33.8% at < 37 weeks, 10.3% at < 32 weeks and 4.4% at < 28 weeks. Spontaneous live preterm birth rates were 22.1% at < 37 weeks, 7.4% at < 32 weeks, and 2.9% at < 28 weeks. 115 women gave birth to 130 babies before 34 weeks: 80% had no major risk factor for preterm birth, 29% had a cervical length scan and less than 15% had an intervention. Over 90% had a live birth, but the neonatal death rate was high (8.5%).

CONCLUSION

Women with moderate risk factors for preterm birth seen in the Cervical Screening Clinic had low rates of intervention and good perinatal outcomes. Most women with major risk factors were appropriately referred and managed by the Preterm Birth Clinic. This two-tier preterm birth prevention service therefore appears safe and effective.

Routine transabdominal cervical length screening in mid-pregnancy for the prevention of preterm birth: Is it good enough to use as a screening test?

BACKGROUND

Preterm birth (PTB) is a major pregnancy complication. There is evidence that a short cervical length in mid-pregnancy may predict women at increased risk of PTB.

AIMS

To evaluate the utility of population-based, transabdominal cervical length (TACL) measurement screening in mid-pregnancy for PTB prediction in women.

MATERIALS AND METHODS

A transabdominal approach was initially performed, with a transvaginal (TVCL) approach offered when the TACL was <35 mm, could not be accurately measured, or the pregnancy had risk factors for PTB. TACL was compared to the directly related TVCL, when both were performed at the same assessment. Women with risk factors of PTB were included when they had both TACL and TVCL measurements performed at the same visit.

RESULTS

Data were provided for 9355 singleton pregnancies from 13 participating imaging centres. A transabdominal approach was used in 9006 (96.3%), including 682 (7.3%) TVCL combined with TACL. There were 349 (3.7%) women who had TVCL only. The median TACL was longer (40 mm) than the TVCL (38 mm). In 682 paired TACL and TVCL measurements, TACL <35 mm correctly identified 96.2% of pregnancies with TVCL <25 mm, compared with 65.4% of cases when using a TACL <30 mm. A TVCL <25 mm occurred in 59 (0.6%) women. A TACL <35 mm was associated with birth <37 weeks of gestation in 12.1% of women and birth <32 weeks of gestation in 3.9%.

CONCLUSIONS

Universal TACL is a feasible option for population screening of cervical length in a low-risk population, progressing to TVCL if the TACL is <35 mm or the cervix cannot be transabdominally accurately measured.

Prediction model for spontaneous preterm birth less than 32 weeks of gestation in low-risk women with mid-trimester short cervical length: a retrospective cohort study

BACKGROUND

A short cervix in mid-trimester pregnancy is a risk factor for spontaneous preterm birth. However, there is currently a lack of predictive models and classification systems for predicting spontaneous preterm birth in these patients, especially those without additional risk factors for spontaneous preterm birth.

METHODS

A retrospective observational cohort study of low-risk singleton pregnant women with a short cervix (≤ 25 mm) measured by transvaginal ultrasonography between 22 and 24 weeks was conducted. A multivariate logistic regression model for spontaneous preterm birth < 32 weeks in low-risk pregnant women with a short cervix was constructed. Moreover, we developed a nomogram to visualize the prediction model and stratified patients into three risk groups (low-, intermediate-, and high-risk groups) based on the total score obtained from the nomogram model.

RESULTS

Between 2020 and 2022, 213 low-risk women with a short cervix in mid-trimester pregnancy were enrolled in the study. Univariate logistic analysis revealed that a high body mass index, a history of three or more miscarriages, multiparity, a short cervical length, leukocytosis, and an elevated C-reactive protein level were associated with spontaneous preterm birth < 32 weeks, but multivariate analysis revealed that multiparity (OR, 3.31; 95% CI, 1.13-9.68), leukocytosis (OR, 3.96; 95% CI, 1.24-12.61) and a short cervical length (OR, 0.88; 95% CI, 0.82-0.94) were independent predictors of sPTB < 32 weeks. The model incorporating these three predictors displayed good discrimination and calibration, and the area under the ROC curve of this model was as high as 0.815 (95% CI, 0.700-0.931). Patients were stratified into low- (195 patients), intermediate- (14 patients) and high-risk (4 patients) groups according to the model, corresponding to patients with scores ≤ 120, 121-146, and > 146, respectively. The predicted probabilities of spontaneous preterm birth < 32 weeks for these groups were 6.38, 40.62, and 71.88%, respectively.

CONCLUSIONS

A noninvasive and efficient model to predict the occurrence of spontaneous preterm birth < 32 weeks in low-risk singleton pregnant women with a short cervix and a classification system were constructed in this study and can provide insight into the optimal management strategy for patients with different risk stratifications according to the score chart.

The vaginal immunoproteome for the prediction of spontaneous preterm birth: A retrospective longitudinal study

Background

Preterm birth is the leading cause of neonatal morbidity and mortality worldwide. Most cases of preterm birth occur spontaneously and result from preterm labor with intact (spontaneous preterm labor [sPTL]) or ruptured (preterm prelabor rupture of membranes [PPROM]) membranes. The prediction of spontaneous preterm birth (sPTB) remains underpowered due to its syndromic nature and the dearth of independent analyses of the vaginal host immune response. Thus, we conducted the largest longitudinal investigation targeting vaginal immune mediators, referred to herein as the immunoproteome, in a population at high risk for sPTB.

Methods

Vaginal swabs were collected across gestation from pregnant women who ultimately underwent term birth, sPTL, or PPROM. Cytokines, chemokines, growth factors, and antimicrobial peptides in the samples were quantified via specific and sensitive immunoassays. Predictive models were constructed from immune mediator concentrations.

Results

Throughout uncomplicated gestation, the vaginal immunoproteome harbors a cytokine network with a homeostatic profile. Yet, the vaginal immunoproteome is skewed toward a pro-inflammatory state in pregnant women who ultimately experience sPTL and PPROM. Such an inflammatory profile includes increased monocyte chemoattractants, cytokines indicative of macrophage and T-cell activation, and reduced antimicrobial proteins/peptides. The vaginal immunoproteome has improved predictive value over maternal characteristics alone for identifying women at risk for early (<34 weeks) sPTB.

Conclusions

The vaginal immunoproteome undergoes homeostatic changes throughout gestation and deviations from this shift are associated with sPTB. Furthermore, the vaginal immunoproteome can be leveraged as a potential biomarker for early sPTB, a subset of sPTB associated with extremely adverse neonatal outcomes.

Funding

This research was conducted by the Perinatology Research Branch, Division of Obstetrics and Maternal-Fetal Medicine, Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, U.S. Department of Health and Human Services (NICHD/NIH/DHHS) under contract HHSN275201300006C. ALT, KRT, and NGL were supported by the Wayne State University Perinatal Initiative in Maternal, Perinatal and Child Health.

Vaginal Progesterone to Prevent Spontaneous Preterm Birth in Women With a Sonographic Short Cervix: The Story of the PREGNANT Trial

The PREGNANT trial was a randomized, placebo-controlled, multicenter trial designed to determine the efficacy and safety of vaginal progesterone (VP) to reduce the risk of birth < 33 weeks and of neonatal complications in women with a sonographic short cervix (10 to 20 mm) in the mid-trimester (19 to 23 6/7 wk). Patients allocated to receive VP had a 45% lower rate of preterm birth (8.9% vs 16.1%; relative risk = 0.55; 95% CI: 0.33-0.92). Neonates born to mothers allocated to VP had a 60% reduction in the rate of respiratory distress syndrome. This article reviews the background, design, execution, interpretation, and impact of the PREGNANT Trial.

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..

Screening vs. no screening for preterm delivery in low-risk singleton pregnancies: comparison by propensity score analysis

PURPOSE

To compare the effect of a policy of screening for spontaneous preterm delivery (SPD) by transvaginal cervical length (CL) measurement versus a no screening policy in the prevention of severe prematurity.

METHODS

Retrospective study on low-risk singleton pregnancies examined at 20-24 weeks. Two cohorts, one with SPD screening and the other without screening, were matched using propensity analysis to create the study groups. Women with short CL were treated with vaginal progesterone and/or cervical cerclage/pessary. The outcomes examined were SPD < 32 weeks (SPD 32) and SPD between 20 and 32 weeks (SPD 20-32).

RESULTS

Screening for SPD was associated with a significant reduction in the rate of SPD at less than 32 weeks (0.3 vs. 0.8%, p = 0.001 in the screened and no screened pregnancies, respectively) and in the rate of SPD 20-32 (0.3 vs. 0.9%, p = 0.005 in the screened and no screened pregnancies, respectively). After adjusting for maternal age, parity, body mass index, smoking and mode of conception, the screening group had significantly lower hazard for SPD 20-32 (HR = 0.36, 95% CI: 0.18-0.75, p = 0.006) and SPD32 (HR = 0.39, 95% CI: 0.19-0.82, p = 0.013).

CONCLUSION

Screening for SPD by transvaginal CL measurement in mid-pregnancy may reduce the incidence of severe prematurity in low-risk singleton pregnancies.

A pragmatic evaluation of the implementation and acceptance of a universal second trimester cervical length screening program in an un-selected population

PURPOSE

To evaluate patients' acceptance of a universal transvaginal ultrasound cervical length (CL) screening program and the feasibility of initiating treatment with progesterone in a clinical setting in women found to have a short cervix.

METHODS

An observational, pragmatic cohort study was conducted at one tertiary care facility from 2012-2015, involving eligible women with singleton pregnancies who accepted and underwent second-trimester CL screening. The primary outcomes were the percentage of women who were eligible and accepting of screening, compliance with progesterone treatment, and the screening value of TVCL in predicting SPTB. Secondary outcomes were the number of women who received progesterone treatment and the rates of SPTB.

RESULTS

Overall cervical length screening acceptance rate was found to be 82.5%. Of the 797 women that underwent screening, 21 women (2.6%) had a TVCL < 25 mm, of whom nine had a TVCL < 20.0 mm. Nineteen of the 21 women with a TVCL < 25 mm were treated with progesterone, with a 94.7% compliance rate. Delivery outcomes were obtained for 767 women. Of those with a TVCL < 25 mm, there was a 35% rate of SPTB as opposed to a 6.3% SPTB rate in those with TVCL > 25 mm. The negative predictive value for SPTB with a TVCL 25 mm or greater was 94.0%.

CONCLUSION

Universal cervical length screening was successfully implemented in 82.5% of the patient population with a high compliance rate with progesterone treatment. Furthermore, there was a higher rate of SPTB in those with a shorter cervix. Based on our outcomes obtained in an observational and pragmatic manner, we showed that incorporating second trimester transvaginal cervical length screening into routine clinical practice is readily accepted and, with the addition of vaginal progesterone treatment, may reduce the rate of prematurity.

Incidentally Found Midtrimester Shortened Cervical Length: Practice Patterns among American Maternal-Fetal Medicine Specialists

OBJECTIVE

The management of incidentally found short cervical length (CL) without prior spontaneous preterm birth (PTB) can vary. While most agree on starting vaginal progesterone, management after CL shortens <10 mm varies. The purpose of this study was to elucidate current practice patterns amongst maternal-fetal medicine (MFM) specialists.

STUDY DESIGN

We conducted an online survey of MFM attending physicians and fellows in the United States from May 2019 to April 2020. The primary outcome was management of varying CL based on gestational age. Variations in management were assessed descriptively.

RESULTS

There were 236 respondents out of 400 eligible surveyed, with a response rate of 59.2%. Universal CL screening was reported by 93.6% (49.6% abdominal and 44.1% transvaginal). Management of short CL varied based on CL measurement, rather than gestational age at presentation. At CL <10 mm, management included cerclage (17.4-18.7%), vaginal progesterone (41.3-41.7%), or cerclage plus vaginal progesterone (43.4%). Between CL of 10 to 20 mm, the majority (77.4-91.9%) would start vaginal progesterone. At CL 21 to 25 mm, management varied between expectant management (45.5-48.5%) or vaginal progesterone (51.1-52.8%). Suture material used was ethylene terephthalate (47.4%) or polypropelene (31.2). Preoperative antibiotic use was reported by 22.3%, while 45.5% used them only if the amniotic membranes were exposed, and 32.2% reported no antibiotic use. Postoperative tocolytic use varied with 19.3% reporting no use, 32.6% using it always, 8.2% only after significant cervical manipulation, 22.7% after the patient is experiencing symptoms, and 17.6% using it only if the cervix is dilated on exam. After cerclage placement, 44.5% continued CL surveillance.

CONCLUSION

Substantial differences of opinion exist among MFM physicians regarding management of incidentally found short CL in patients without history of PTB. The differences in responses obtained highlight the need for evidence-based guidelines for managing this clinical scenario.

KEY POINTS

· There is lack of consensus on the management of incidentally found shortened CL.. · The purpose of this study was to elucidate current trends in CL screening and management.. · Substantial differences of opinion exist regarding management of incidentally found short CL..

Use and misuse of ultrasound in obstetrics with reference to developing countries

Maternal and neonatal health is one of the main global health challenges. Every day, approximately 800 women and 7,000 newborns die due to complications during pregnancy, delivery, and neonatal period. The leading causes of maternal death in sub-Saharan Africa are obstetric hemorrhage (28.8%), hypertensive disorders in pregnancy (22.1%), non-obstetric complications (18.8%), and pregnancy-related infections (11.5%). Diagnostic ultrasound examinations can be used in a variety of specific circumstances during pregnancy. Because adverse outcomes may also arise in low-risk pregnancies, it is assumed that routine ultrasound in all pregnancies will enable earlier detection and improved management of pregnancy complications. The World Health Organization (WHO) estimated in 1997 that 50% of developing countries had no access to ultrasound imaging, and available equipment was outdated or broken. Unfortunately, besides all the exceptional benefits of ultrasound in obstetrics, its inappropriate use and abuse are reported. Using ultrasound to view, take a picture, or determine the sex of a fetus without a medical indication can be considered ethically unjustifiable. Ultrasound assessment when indicated should be every woman's right in the new era. However, it is still only a privilege in some parts of the world. Investment in both equipment and human resources has been clearly shown to be cost-effective and should be an obligatory step in the improvement of health care. Well-developed health systems should guide developing countries, creating principles for the organization of the health system with an accent on the correct, legal, and ethical use of diagnostic ultrasound in pregnancy to avoid its misuse. The aim of the article is to present the importance of correct and appropriate use of ultrasound in obstetrics and gynecology with reference to developing countries.

The perceptions of obstetric care providers about cervical length screening for preterm birth prevention

BACKGROUND

Routine cervical length (CL) measurement at the mid-pregnancy ultrasound is a central recommendation of the Western Australian Preterm Birth Prevention Initiative (Initiative).

AIM

To evaluate the perceptions and changes in practice of Western Australian obstetric care providers regarding routine CL screening for preterm birth (PTB) prevention following the Initiative introduction.

METHODS

Two self-administered questionnaires were completed by providers from a range of practices. The first was during site visits with the Initiative Outreach team in 2015-2016. The questionnaire was re-issued in 2021 via online dissemination. Participant demographic data and opinions on CL screening for PTB prevention were collected.

RESULTS

Two hundred and fourteen providers participated in 2015-2016 and 109 in 2021. In both surveys, providers were more likely to discuss transvaginal CL screening with high-risk women (48.1%, 76.1%; P < 0.001) compared with low-risk (7.5%, 18.3%; P = 0.002) and the importance of CL screening (13.5%, 40.4%; P < 0.001), in 2015-2016 and 2021, respectively. Responses relating to CL screening, including what constitutes a short cervix on ultrasound were varied. A transabdominal CL <35 mm was classified as short by 46.2% and 37.6% and <25 mm on transvaginal ultrasound by 49.1% and 64.2%, in the respective surveys. Most providers ceased progesterone (68.6%, 75.2%) at >28 weeks gestation.

CONCLUSIONS

Providers focused on women with overt PTB risk factors, rather than a universal CL screening approach. Although there was improvement between the surveys, the definition of what constitutes a short cervix on ultrasound and how to treat and monitor women with a short CL remained varied.

Evaluation of Uterocervical Angle and Cervical Length as Predictors of Spontaneous Preterm Birth

Aim The aim of this article was to evaluate uterocervical angle (UCA) and cervical length (CL) measured at 16 to 24 weeks of gestation using transvaginal sonography (TVS) as predictors of spontaneous preterm birth.

Methods In this prospective study, TVS was performed in 159 primigravidas with a singleton, uncomplicated pregnancy at 16 to 24 weeks of gestation to measure the anterior UCA and CL. All the cases were followed until labor to document gestational age at delivery.

Results The risk of spontaneous preterm birth was higher in women with obtuse UCA (>95 degrees) with sensitivity of 86.7%, specificity of 93.0%, positive predictive value of 83.0%, negative predictive value of 94.6%, and p-value of <0.001. The difference between the means was statistically significant (p-value < 0.001). UCAs ≥105degrees and 95 to 105 degrees were found to be significantly associated with spontaneous preterm births at <34 weeks and 34 to 37 weeks, respectively. CL <2.5 cm was found to predict spontaneous preterm births at <37 weeks with sensitivity of 31.1%, specificity of 95.6%, and p-value of <0.001. UCA was found to be a better predictor of spontaneous preterm birth with a higher coefficient of variation (56.4%) when compared with CL (16.9%).

Conclusions UCA proved to be a novel ultrasound parameter that can serve as a better predictor of spontaneous preterm births in comparison to CL. A strong correlation exists between obtuse UCA and a risk of spontaneous preterm birth.

Controversies in treatment practices of the mother-infant dyad at the limit of viability

In the setting of threatened extreme preterm birth, balancing maternal and fetal risks and benefits in order to choose the best available treatment options is of utmost importance. Inconsistency in treatment practices for infants born between 22 and 24 weeks of gestatotional age may account for inter-hospital variation in survival rates with and without impairment. Most importantly, non-biased and accurate information must be presented to the family as soon as extremely preterm birth is suspected, including counseling on morbidities and mortality associated with delivery at the limits of viability. This review will focus on different therapeutic medical and surgical practices available for threatened extremely preterm birth to improve fetal and maternal outcomes while highlighting the importance of patient-centered approaches.

Ultrasonographic Transabdominal Measurement of Uterine Cervical Length for the Prediction of a Midtrimester Short Cervix

OBJECTIVE

This study was aimed to estimate the value of transabdominal (TA) ultrasound measurement of cervical length (CL), as an alternative of transvaginal (TV) ultrasound, for universal screening of short cervix in the midtrimester.

STUDY DESIGN

We conducted a prospective cohort study of nulliparous women with singleton pregnancy at 20 to 24 weeks of gestation. All participants underwent TA ultrasound followed by TV ultrasound with acquisitions of images and videos of the uterine cervix. A second sonographer, blinded to the participants' data and pregnancy outcomes, measured the CL using TA and TV images and videos. Pearson's correlation test and receiver operating characteristic (ROC) curve analyses were performed.

RESULTS

A total of 805 participants were recruited, including 780 (97%) where TA CL measurement was feasible. We observed a strong correlation of CL between TA and TV (correlation coefficient: 0.57; p < 0.0001) with a mean TA measurement being 4 mm (95% confidence interval [CI]: -6 to 14 mm) below the mean TV measurement (mean of differences: 5 ± 4 mm). We observed that a TA CL <30 mm was highly predictive of a short cervix defined as a TV CL ≤25 mm (area under the ROC curve: 0.97; 95% CI: 0.95-0.99; p < 0.0001) with a sensitivity of 100% and a false-positive rate of 22%.

CONCLUSION

Universal short cervix screening in nulliparous women could be performed using TA ultrasound, which could allow the avoidance of TV ultrasound in more than three quarter of women. In low-risk population, TV ultrasound could be reserved to women with TA CL <30 mm.

KEY POINTS

· Cervical length (CL) measurement with transabdominal (TA) ultrasound is feasible in most cases and is strongly correlated with CL measured with transvaginal (TV) ultrasound.. · Using a cut-off of 30 mm for TA ultrasound as a first-step screening of short cervix in nulliparous women, three-quarter of TV ultrasound could have been avoided.. · Use of TA CL screening could alleviate some of the logistical challenges of universal TV CL screening..

Comparison of Transabdominal and Transvaginal Sonograms in Evaluation of Cervical Length During Pregnancy

Objective:

A short cervix during pregnancy indicates a higher risk of preterm delivery. Transvaginal sonography is widely used for the detection of a short cervix. The literature indicates that 21–24 weeks is the most sensitive gestational age to assess transvaginal cervical length (TV CL) of ≤2.5 cm for potential preterm delivery. Pregnancies between 18 and 20 weeks’ gestation are generally performed transabdominally; thus, it could be beneficial to have a recognized correlation between the transabdominal cervical length (TA CL) measurement and the TV CL measurement at this earlier time period.

Materials and Methods:

An online database search produced 13 research articles to be reviewed. Inclusion criteria consisted of TA CL and TV CL assessment of singleton pregnancies with intact membranes.

Results:

Findings indicate high diagnostic yield when a TA CL of <2.9 cm or TV CL of <2.5 cm is used for defining a shortened cervix when measured between 18 and 20 weeks’ gestation.

Conclusion:

This review of the literature indicates a correlation between average TA CL and average TV CL measurements, although the relationship widens as CLs become shorter.

Utility of follow-up cervical length screening in low-risk women with a cervical length of 26 to 29 mm

BACKGROUND

In women with a previous preterm birth, a protocol for serial cervical length screening has been studied and recommended for the identification and treatment of a short cervix. Cervical length screening along with vaginal progesterone has been suggested for low-risk women with singleton pregnancies to treat a short cervix and reduce preterm birth. However, specific protocols for single vs serial ultrasound measuring cervical length in this population are not established. Cost-effectiveness of universal cervical length screening depends on the cost of screening; follow-up of borderline measurements can contribute to increased costs with uncertain benefit.

OBJECTIVE

This study aimed to determine the utility of follow-up cervical length screening in otherwise low-risk women with singleton pregnancies with a midtrimester cervical length measurement of 26 to 29 mm through the assessment of the rate of short cervix (≤25 mm) on follow-up ultrasound and subsequent delivery outcomes.

STUDY DESIGN

This was a 2-year retrospective cohort study at a single urban institution of women with singleton pregnancies with no previous spontaneous preterm birth and an initial transvaginal ultrasound cervical length measurement of 26 to 29 mm identified during universal cervical length screening at time of anatomy ultrasound (18 0/7 to 22 6/7 weeks' gestation). The primary outcome was the rate of short cervix (defined as ≤25 mm on transvaginal ultrasound) on follow-up ultrasound at <24 weeks' gestation. Secondary outcomes included the rate of spontaneous preterm birth (<37 and <34 weeks' gestation).

RESULTS

During the study period, there were 2801 women with singleton pregnancies at 18 0/7 to 22 6/7 weeks' gestation with transvaginal ultrasound cervical length screening at time of anatomy scan. Among those women, 201 had a cervical length of 26 of 29 mm, and 184 (7%) had no previous spontaneous preterm birth and were included in the study. Furthermore, 144 women (78%) had a follow-up cervical length completed before 24 weeks' gestation. The mean follow-up interval was 1.5±0.6 weeks. Overall, the percentage of short cervix (≤25 mm) on follow-up was 15% (n=21). Baseline characteristics were similar, but the initial cervical length measurement was shorter in women who subsequently developed a short cervix (26.7±0.8 vs 27.8±1.0; P<.01). Delivery outcomes were available for 126 patients. The rate of spontaneous preterm birth at <37 weeks' gestation in women with an initial cervical length 26 to 29 mm and subsequent short cervix was significantly higher than the rate of spontaneous preterm birth in a historical cohort of low risk women with an initial cervical length >25 mm (16% vs 3%; P=.03). The rate of spontaneous preterm birth at <34 weeks' gestation in women with a subsequent short cervix was 11% (2 of 19).

CONCLUSION

Here, approximately 15% of low-risk women with singleton pregnancies with a midtrimester cervical length measurement of 26 to 29 mm will experience cervical shortening of ≤25 mm before 24 weeks' gestation. Compared to women with singleton pregnancies without a history of preterm birth, the rate of spontaneous preterm birth (16%) in women with an initial cervical length of 26 to 29 mm and a subsequent cervical shortening of ≤25 mm is significantly higher. A total of 111 follow-up ultrasounds measuring cervical length would be required to prevent 1 early preterm birth at <34 weeks' gestation.

Effects of prophylactic vaginal progesterone administration on mild cervical shortening (TROPICAL study): a multicenter, double-blind, randomized trial

Vaginal progesterone reduces the preterm birth frequency among high-risk women with a cervical length ≤25 mm at midtrimester. However, the strategy may promote no substantial reduction in overall preterm birth rates, because such high-risk women are only approximately 2% of all pregnant women, which restrict the number of participants. Our purpose was to determine whether prophylactic vaginal progesterone administration can preserve cervical length and reduce preterm birth rates among women with mild cervical shortening.This multicenter, parallel-arm, double-blind, randomized, placebo-controlled trial involved vaginal progesterone administration (200 mg daily from 16 to 33 weeks of gestation) among asymptomatic women with a singleton pregnancy and a sonographic cervical length of 25 to <30 mm between 16 and 23 weeks of gestation. The primary and secondary endpoints were cervical shortening rates at 34 weeks of gestation and preterm birth rates, respectively. The trial was registered at the University Hospital Medical Information Network (UMIN000013518) in Japan.Between April 2014 and March 2018, 119 women were randomly assigned to the progesterone group (n = 59) and the placebo group (n = 60). No significant differences in the frequency of women with a cervical length ≥20 mm at 34 weeks of gestation were observed between both groups. All preterm births occurred after 34 weeks of gestation, except for one patient in the placebo group. The progesterone group had a lower rate of preterm birth before 37 weeks than the placebo group (3.4% vs. 15.0%, respectively; p < .05).Despite having no effect on preserving cervical length, prophylactic vaginal progesterone administration reduced preterm birth frequency among women with mild cervical shortening. Our results are suggesting that women with mild cervical shortening are at risk for late preterm birth and the need for expanding progesterone treatment indications to include not only high-risk but also low-risk populations.

Appalachian Women's perspectives on preterm birth and transvaginal ultrasound cervical length screening: Implications for addressing disparities in preterm birth

PURPOSE

Preterm birth (PTB), a pressing issue for US maternal-child health, disproportionately impacts women in Appalachia. Transvaginal ultrasound (TVU) cervical length (CL) screening is the most accurate PTB risk predictor but remains underutilized. This study characterizes the knowledge, attitudes and beliefs of patients with prior PTB concerning PTB prevention efforts and TVU CL screening.

METHODS

Participants were recruited from community-based health centers in Appalachian Kentucky. Semi-structured interviews and likert-scale surveys were conducted with 22 pregnant women with a history of spontaneous PTB. Methods for data collection were guided by the Consolidated Framework for Implementation Research (CFIR).

RESULTS

Most participants reported that TVU was uncomfortable, but none refused it. Most women were able to articulate the benefits of TVU, but several had concerns about its safety in pregnancy. Participants suggested that pregnant women receive more PTB education and self-advocate. They urged providers to take patient concerns seriously, and better educate patients on PTB risks and TVU safety.

DISCUSSION

Our study contributes crucial insights about the experience of a vulnerable population as it pertains to PTB prevention and the uptake of TVU CL screening. Our findings emphasize the need for increased efforts to better educate patients on the impact of prematurity and the safety and benefits of TVU CL screening as an evidence-based strategy for PTB prevention.

The Impact of Routine Transvaginal Ultrasound Measurement of the Cervical Length on the Prediction of Preterm Birth: A Retrospective Study in a Tertiary Hospital

Preterm birth (PTB) is a major obstetric problem associated with high rates of neonatal morbidity and mortality. The prevalence of PTB has not changed in the last decade; thus, the establishment of a screening test and effective treatment are warranted. Transvaginal ultrasound measurement of the cervical length (TUCL) has been proposed as an effective method to screen pregnant women at a higher risk of experiencing PTB.

OBJECTIVE

 To evaluate the applicability and usefulness of second-trimester TUCL to predict PTB in a cohort of Portuguese pregnant women.

METHODS

 Retrospective cross-sectional cohort study including all singleton pregnant women who performed their second-trimester ultrasound (between weeks 18 and 22 + 6 days) from January 2013 to October 2017 at Centro Hospitalar Universitário São João.

RESULTS

 Our cohort included 4,481 women. The prevalence of spontaneous PTB was of 4.0%, with 0.7% occurring before the 34th week of gestation. The mean TUCL was of 33.8 mm, and percentiles 3, 5 and 10 corresponded to TUCLs of 25.0 mm, 27.0 mm and 29.0 mm respectively. The multiple logistic regression analysis, including maternal age, previous PTB and cervical surgery showed a significant negative association between TUCL and PTB, with an odds ratio (OR) of 0.92 (95% confidence interval [95%CI]: 0.90-0.95; p < 0.001). The use of a TUCL of 20 mm is the best cut-off, when compared with the 25-mm cut-off, improving the prediction of risk.

CONCLUSION

 The present study showed an inverse association between TUCL and PTB, and that the inclusion of other risk factors like maternal age, previous PTB and cervical surgery can improve the screening algorithm. Furthermore, it emphasizes that the TUCL cut-off that defines short cervix can differ according to the population.

Improving Utilization of Aspirin for Prevention of Preeclampsia in a High-Risk Urban Cohort: A Prospective Cohort Study

OBJECTIVE

This study aimed to evaluate the utilization of aspirin for preeclampsia prevention before and after implementation of a screening tool during nuchal translucency (NT) ultrasound.

STUDY DESIGN

One-year prospective cohort study of patients at high risk for preeclampsia after the implementation of a screening tool (postscreen) administered to all patients at check in for NT (11-13 weeks) ultrasound. Prospective cohort was compared with one-year retrospective cohort (prescreen) the year prior (2017). All patients who presented for NT ultrasound in both cohorts were evaluated for the presence of one or more risk factor for preeclampsia with screening tool collected prospectively and chart review retrospectively. Provider recommendation for aspirin determined by documentation in prenatal record. Primary outcome was rate of provider recommendation for aspirin pre versus post screening tool, compared by Chi-square test and adjusted for potential confounders with multiple regression analysis.

RESULTS

Pre- (n = 156) and postscreen (n = 136) cohorts were similar except for race and multifetal gestation. Prescreen, rate of provider recommendation for aspirin was 74%. Of those with prior preeclampsia, 96% were recommended aspirin, compared with 64% of patients with other risk factors (p < 0.001). Postscreen, provider recommendation of aspirin improved to 95% (p < 0.001). Rate of preeclampsia/gestational hypertension were similar between cohorts; however, there was a reduced adjusted risk in overall preterm birth <37 weeks (adjusted odds ratio [aOR] = 0.50 [0.25-0.99]) and preterm birth <34 weeks (aOR = 0.33 [0.13-0.88]) postscreening tool implementation.

CONCLUSION

Prior to implementation of a simple screening questionnaire, approximately 25% of high risk patients did not receive the recommendation of aspirin for preeclampsia prevention. High-risk patients who lack a history of preeclampsia were less likely to be advised of aspirin prophylaxis. Use of a simple universal screening tool at time of NT ultrasound significantly improved utilization of aspirin for preeclampsia prevention and may improve patient outcomes.

KEY POINTS

· Despite recommendations, aspirin use for preeclampsia prevention is suboptimal.. · High-risk patients who lack a history preeclampsia were less likely to be advised of aspirin use.. · A simple universal screening tool can significantly improve aspirin utilization..

The perceptions of pregnant women about cervical length screening for preterm birth prevention

BACKGROUND

The Western Australian Preterm Birth Prevention Initiative was officially launched in November 2014. It demonstrated an initial decrease in the preterm birth rate in Western Australia. One of the key points of this initiative is the routine ultrasound measurement of the cervical length in mid-pregnancy.

AIM

The aim of this study was to evaluate the perceptions and attitudes of Western Australian women regarding transvaginal cervical length (TVCL) screening for preterm birth prevention.

MATERIALS AND METHODS

Self-administered questionnaires were completed by pregnant women before and after their mid-trimester obstetric ultrasound. Maternal demographical and medical data were collected in addition to opinions of TVCL screening.

RESULTS

A total of 598 women participated with the maternal age range representative of the Western Australian obstetric population. There was a high rate of acceptance of TVCL imaging, with 2% of the 149 women declining a transvaginal ultrasound (TVU) offered in this study, 1.5% refusing a TVU in the past and 5.7% reporting that they would have a concern in having a TVU in the future. Women stated that they either had declined TVCL in the past (11%) or would decline in the future (30.7%) as they wanted to discuss the procedure with their clinician first, had been advised not to have a TVU by their clinician (11% in the past and 47.7% in the future) or felt uncomfortable with the operator (22% at a previous TVU and 34.4% in the future).

CONCLUSION

Pregnant women participating in this study had a high acceptance of TVCL screening for preterm birth prevention.

Identifying the barriers to universal cervical length screening for preterm birth prevention at a tertiary hospital in Thailand (patient's perspectives): implementation research

PURPOSE

To identify patient perspectives of barriers to cervical length screening to prevent preterm births.

METHODS

In Phase I of this prospective descriptive implementation study, 40 pregnant women of up to 24 week gestation were interviewed. Phase II comprised questionnaire development and data validation. The questionnaire was subsequently administered to 400 participants in Phase III.

RESULTS

Most participants (74.3%) realised preterm babies have complications and high care costs (53%). They recognised that premature-birth risk identification enables appropriate pregnancy care (93.8%), but they were unaware that cervical length measurements indicate the risk (59.5%). The participants who were aware wanted to be examined (63.5%) because of concern about preterm birth (95.8%). Husbands were reported to influence decision-making about screening (81.3%) and subsequent treatment (42.5%). If the associated costs were subsidised, the majority of participants (67.3%) would undergo screening.

CONCLUSION

Physicians do not explain ways to prevent preterm births. Government policy on preventing preterm births is not well established. Screening and treatment costs are major barriers.

TRIAL REGISTRATION

Thai Clinical Trials Registry (TCTR) number: TCTR20190813003.

Personalized assessment of cervical length improves prediction of spontaneous preterm birth: a standard and a percentile calculator

BACKGROUND

A sonographic short cervix (length <25 mm during midgestation) is the most powerful predictor of preterm birth. Current clinical practice assumes that the same cervical length cutoff value should apply to all women when screening for spontaneous preterm birth, yet this approach may be suboptimal.

OBJECTIVE

This study aimed to (1) create a customized cervical length standard that considers relevant maternal characteristics and gestational age at sonographic examination and (2) assess whether the customization of cervical length evaluation improves the prediction of spontaneous preterm birth.

STUDY DESIGN

This retrospective analysis comprises a cohort of 7826 pregnant women enrolled in a longitudinal protocol between January 2006 and April 2017 at the Detroit Medical Center. Study participants met the following inclusion criteria: singleton pregnancy, ≥1 transvaginal sonographic measurements of the cervix, delivery after 20 weeks of gestation, and available relevant demographics and obstetrical history information. Data from women without a history of preterm birth or cervical surgery who delivered at term without progesterone treatment (N=5188) were used to create a customized standard of cervical length. The prediction of the primary outcome, spontaneous preterm birth at <37 weeks of gestation, was assessed in a subset of pregnancies (N=7336) that excluded cases with induced labor before 37 weeks of gestation. Area under the receiver operating characteristic curve and sensitivity at a fixed false-positive rate were calculated for screening at 20 to 23 6/7, 24 to 27 6/7, 28 to 31 6/7, and 32 to 35 6/7 weeks of gestation in asymptomatic patients. Survival analysis was used to determine which method is better at predicting imminent delivery among symptomatic women.

RESULTS

The median cervical length remained fundamentally unchanged until 20 weeks of gestation and subsequently decreased nonlinearly with advancing gestational age among women who delivered at term. The effects of parity and maternal weight and height on the cervical length were dependent on the gestational age at ultrasound examination (interaction, P<.05 for all). Parous women had a longer cervix than nulliparous women, and the difference increased with advancing gestation after adjusting for maternal weight and height. Similarly, maternal weight was nonlinearly associated with a longer cervix, and the effect was greater later in gestation. The sensitivity at a 10% false-positive rate for prediction of spontaneous preterm birth at <37 weeks of gestation by a short cervix ranged from 29% to 40% throughout pregnancy, yet it increased to 50%, 50%, 53%, and 54% at 20 to 23 6/7, 24 to 27 6/7, 28 to 31 6/7, and 32 to 35 6/7 weeks of gestation, respectively, for a low, customized percentile (McNemar test, P<.001 for all). When a cervical length <25 mm was compared to the customized screening at 20 to 23 6/7 weeks of gestation by using a customized percentile cutoff value that ensured the same negative likelihood ratio for both screening methods, the customized approach had a significantly higher (about double) positive likelihood ratio in predicting spontaneous preterm birth at <33, <34, <35, <36, and <37 weeks of gestation. Among symptomatic women, the difference in survival between women with a customized cervical length percentile of ≥10th and those with a customized cervical length percentile of <10th was greater than the difference in survival between women with a cervical length ≥25 mm and those with a cervical length <25 mm.

CONCLUSION

Compared to the use of a cervical length <25 mm, a customized cervical length assessment (1) identifies more women at risk of spontaneous preterm birth and (2) improves the distinction between patients at risk for impending preterm birth in those who have an episode of preterm labor.

The Short Cervix: A Critical Analysis of Diagnosis and Treatment

A short cervix in the second trimester is a significant risk factor for spontaneous preterm birth, preterm prelabor rupture of membranes, and subsequent adverse perinatal outcome. The pathophysiology is complex and multifactorial with inflammatory and/or infectious processes often involved. Biomarkers have been developed in an effort to predict preterm birth with varying degrees of success. The treatment options of cerclage, progesterone, pessary, and combination therapy are reviewed. Evidence-based protocols are summarized for singleton and multiple gestation.

Predictors of Early Preterm Birth Despite Vaginal Progesterone Therapy in Singletons with Short Cervix

OBJECTIVE

This study aimed to identify the incidence of and risk factors for early preterm birth (PTB) (delivery <34 weeks) in women without prior PTB and current short cervix (≤20 mm) prescribed vaginal progesterone.

STUDY DESIGN

Retrospective cohort study of singletons without prior PTB diagnosed with short cervix (≤20 mm) between 18^0/7 and 23^6/7 weeks. Women who accepted vaginal progesterone and had delivery outcomes available were included. Demographic/obstetric history, cervical length, and pregnancy characteristics compared between women with early PTB versus delivery ≥34 weeks. Multiple logistic regression analysis used to identify predictors; odds ratio for significant factors used to generate a risk score. Risk score and risk of early PTB assessed with receiver operating characteristic curve (ROCC). Perinatal outcomes compared by risk score.

RESULTS

Among 109 patients included, 29 (27%) had a spontaneous PTB <34 weeks. In univariate analysis, only gestational age at ultrasound, presence funneling, and mean cervical length were significantly different between those with and without early sPTB. With multiple logistic regression analysis, only gestational age at diagnosis (odds ratio [OR]: 0.66; 95% confidence interval [CI]: 0.46-0.96; p = 0.028) and index cervical length (OR: 0.84; 95% CI: 0.76-0.93; p = 0.001) remained significantly associated with early PTB. ROCC for the risk score incorporating cervical length and gestational age was predictive of early PTB with an AUC of 0.76 (95% CI: 0.67-0.86; p < 0.001). A high-risk score was predictive of early PTB with a sensitivity of 79%, specificity of 75%, positive predictive value of 54%, and negative predictive value of 91%. Women with a high-risk score had worse perinatal outcomes compared with those with low-risk score.

CONCLUSION

A total of 27% of patients with short cervix prescribed vaginal progesterone will have a sPTB < 34 weeks. Patients at high risk for early PTB despite vaginal progesterone therapy may be identified using gestational age and cervical length at diagnosis of short cervix. Given the narrow window for intervention after diagnosis of short cervix, this has important implications for clinical care.

Universal transvaginal cervical length screening during pregnancy increases the diagnostic incidence of low-lying placenta and placenta previa

BACKGROUND

Universal transvaginal cervical length screening has been increasingly implemented with both positive and negative consequences.

OBJECTIVE

In this study, we described the diagnostic incidence of low-lying placenta and placenta previa with the implementation of universal transvaginal cervical length screening.

STUDY DESIGN

This is a retrospective cohort study of women undergoing midtrimester universal transvaginal cervical length screening. The primary outcome was the rate of transvaginal diagnosis of low-lying placenta or placenta previa using midtrimester universal transvaginal cervical length screening.

RESULTS

This study included 1982 midtrimester ultrasounds, of which 211 indicated a low-lying placenta or placenta previa on either transabdominal or transvaginal ultrasound. With transvaginal ultrasound, a low-lying placenta or placenta previa was diagnosed in 211 women (10.6% of the study population). Of the 211 patients with a low-lying placenta or placenta previa, 90 (42.6%) had a false-negative result, diagnosed using only transvaginal ultrasound; 112 (53.1%) had a true-positive result; and 9 (4.3%) had a false-positive result. The relative risk of having an abnormal finding on ultrasound with the addition of universal transvaginal cervical length screening was 9.2 (95% confidence interval, 4.6-18.1). Of the low-lying placenta or placenta previa diagnosed using midtrimester universal transvaginal cervical length screening, 98.9% resolved (95% confidence interval, 93.7-99.97).

CONCLUSION

Implementation of universal transvaginal cervical length screening increases the diagnostic incidence of low-lying placenta or placenta previa without an increase in the diagnoses that persist to term, which comes at the cost of increased follow-up ultrasounds and potentially increased anxiety for the patient.

Time required to complete transvaginal cervical length in women receiving universal cervical length screening for preterm birth prevention

BACKGROUND

Preterm birth contributes to over one-third of infant deaths, and although there are several risk factors for preterm birth few tests predict this obstetric complication. Midtrimester transvaginal cervical length (TVCL) screening is currently the best clinical predictor of spontaneous preterm birth and has been suggested to be applied universally. Although several studies have examined the cost-efficacy of universal screening, the time consumption and resultant time management has not been examined.

OBJECTIVE

We aim to quantitate the time requirement for transvaginal cervical length (TVCL) screening with the implementation of universal TVCL screening.

Study design: This is a retrospective cohort study of women undergoing cervical length screening after implementation of universal Transvaginal Cervical Length (TVCL) screening at a university setting over a 1-year period. The primary outcome was time in minutes for TVCL screening from completion of transabdominal to completion of transvaginal ultrasound.

RESULTS

This study included 2803 ultrasounds, 1673 of which involved completion of a TVCL after completion of abdominal imaging between 16 0/7 and 23 6/7 weeks of gestation. The mean duration of cervical length screening was 9.8 min (standard deviation [SD], 4.0 min). The time range was less than 1 min to 48 min. For women obtaining cervical lengths, 4.2% required less than 5 additional minutes to perform cervical length screening, 52.1% (872), required less than 10 additional minutes. The majority, 91.8%, of ultrasounds required less than 15 min to complete. Ultrasounds performed in private practice sites required less time compared to those at teaching sites (8.2 ± 3.1 min versus 10.2 ± 4.1 min, p < .001). No significant time improvement occurred after 6 months of universal TVCL screening, with the first 6 months average of 10.1 min versus 9.6 min in the later half, p = .61.

CONCLUSION

Implementation of a universal TVCL program adds an average of 10 min to each ultrasound exam. This additional time does diminish with increasing experience with TVCL, but not to a significant degree.

Preterm Birth Prevention in Appalachian Kentucky: Understanding Barriers and Facilitators Related to Transvaginal Ultrasound Cervical Length Surveillance Among Prenatal Care Providers

Background: Appalachian Kentucky has higher-than-average rates of preterm birth (PTB)-a health disparity associated with increased maternal and fetal/neonatal morbidity and neonatal mortality. Transvaginal ultrasound (TVU) cervical length measurement is the best predictor of PTB risk, but is underutilized in Appalachia. This study explores prenatal care providers' TVU-related knowledge and practices, and identifies barriers and facilitators, which impact the adoption of this evidence-based technology. Materials and Methods: This study recruited providers from three Appalachian Kentucky health care sites. Prenatal care providers took part in semistructured interviews and completed brief survey scales. Questions focused on PTB knowledge, TVU-related barriers, and suggestions for clinician and/or patient-focused interventions. Transcripts were coded using a multistage process based in grounded theory. Descriptive statistics were calculated. Results: Eleven physicians, one nurse practitioner, one physician assistant, and one midwife completed interviews. Average participant age was 44 years with 17 years in practice; 43% of providers were female. Practitioners described the sociodemographic characteristics, health behaviors (e.g., smoking, opioid abuse), and comorbid conditions (e.g., obesity, hypertension, and diabetes) endemic in Appalachia that heightened their patients' PTB risk. TVU use was reported as important by all respondents, but not all were satisfied with their level of training. The most commonly identified barriers to TVU were patient access to transportation and social support. Participants stressed a need for changing community perceptions regarding consequences of PTB. Conclusions: Providers identified multiple TVU-related barriers and facilitators. These data will inform the design of a multifaceted dissemination and implementation strategy targeting PTB prevention in Appalachia.

3D ultrasound as a surgical quality control of conization in patients with severe dysplasia: a prospective study

Purpose

To compare the techniques for cone measurement with ultrasound to determine the size of the resected tissue and to evaluate parameters which may be relevant for stratifying women at risk who need surveillance when pregnant.

Methods

The present study included women with a pathological cervical biopsy. Cervical length and volume were determined by transvaginal ultrasound prior to conization. The pathologist measured the volume of the removed tissue by the fluid displacement technique and using a ruler. A repeat transvaginal ultrasound was performed during a follow-up visit. Factors affecting cone volume as well as the correlation between measurement techniques were analyzed.

Results

A total of 28 patients underwent cervical excision treatment. The mean cervical volumes measured sonographically before and after the operation were 17.72 ± 7.34 and 13.21 ± 5.43 cm³, respectively. The proportion of volume excised was 25.50 ± 17.43%. A significant correlation was found between the cone depth and the cone volume measured by the fluid displacement technique, and histopathologically and sonographically measured difference in cervical volume. The interobserver reliability coefficient was > 0.9. Analyzing influential parameters, only age affected the extent of cone volume and the correlation between the three measurement techniques.

Conclusion

Commonly applied techniques of cervical and cone measurement are equivalent and interchangeable. Our ultrasound data show variety in the volume and length of the cervix, and in the proportion of the volume excised at conization. Ultrasound measurements may help the surgeon to estimate not only the dimension of the remaining cervix but also its function.

ACR Appropriateness Criteria® Assessment of Gravid Cervix

Preterm birth remains the leading cause of perinatal morbidity and mortality. Although the greatest risk factor for preterm birth is a history of prior preterm birth, a short cervical length (≤25 mm) before 24 weeks' gestational age is also associated with increased risk of spontaneous preterm delivery. As such, cervical length assessment has become of particular interest in predicting those patients at risk for preterm birth. Other clinical scenarios (eg, preterm labor, induction of labor, and active labor) may arise, in which assessment of the cervix may be of interest. Ultrasound is the mainstay imaging modality for assessing the gravid cervix, with transvaginal ultrasound recommended in patients at high risk for preterm birth or suspected preterm labor. Transperineal ultrasound is an alternate approach in those cases where transvaginal ultrasound in contraindicated. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Predictive Value of Midtrimester Universal Cervical Length Screening Based on Parity

OBJECTIVES

To evaluate the effect of parity on performance characteristics of midtrimester cervical length (CL) in predicting spontaneous preterm birth (sPTB) before 37 weeks.

METHODS

This was a retrospective cohort study of 13,508 women with no history of sPTB undergoing universal transvaginal CL screening at 17 to 23 weeks' gestation from 2011 to 2016. Patients who declined screening or with unknown delivery outcomes were excluded. Areas under the receiver operator characteristic curves were used to assess and compare the predictive ability of CL screening for sPTB. The sensitivity, specificity, and positive and negative predictive values were estimated for specific CL cutoffs for prediction of sPTB.

RESULTS

There were 20,100 patients, of whom 2087 (10%) declined screening and 4505 (22%) did not meet inclusion criteria. Of the remaining 13,508 patients, 43% were nulliparous. The incidence rates of sPTB were 6.5% in nulliparas and 4.9% in multiparas (P < .001). The mean CLs were 39.9 mm in nulliparas and 41.8 mm in multiparas (P < .001), and those of the first percentiles were 19.0 mm in nulliparas and 24.0 mm in multiparas. Cervical length was significantly more predictive of sPTB in nulliparas (area under the curve, 0.67; 95% confidence interval, 0.63-0.70; versus 0.61, 95% confidence interval, 0.57-0.63; P = .008). At CL cutoffs of 10, 15, 20, and 25 mm or less, the sensitivity was lower in multiparas, and the specificity was comparable between the groups.

CONCLUSIONS

Midtrimester CL is less predictive of sPTB in multiparas compared to nulliparas. The poor predictive ability, especially in multiparas, calls into question the value of universal CL screening in this population.

Predicting asymptomatic cervical dilation in pregnant patients with short mid-trimester cervical length: A secondary analysis of a randomized controlled trial

INTRODUCTION

Second trimester asymptomatic cervical dilation is a significant risk factor for early preterm birth. The objective of this study is to evaluate whether transvaginal ultrasound cervical length (CL) predicts asymptomatic cervical dilation on physical exam in women with short cervix (CL ≤25 mm) and no prior preterm birth.

MATERIAL AND METHODS

Secondary analysis of a randomized trial on pessary in asymptomatic singletons without prior preterm birth diagnosed with CL ≤25 mm between 18+0/7 and 23+6/7  weeks. Participants had transvaginal ultrasound and physical cervical exam and were randomized to pessary or no pessary with all patients with cervical length ≤20 mm offered vaginal progesterone. The primary outcome was to determine whether CL was predictive of asymptomatic physical cervical dilation ≥1 cm using receiver operating characteristic curve.

RESULTS

In all, 119 women were included. Based on receiver operating characteristic curve, CL ≤11 mm was best predictive of cervical dilation ≥1 cm, with 75% sensitivity, 80% specificity, and area under the curve 0.73 (0.55-0.91), P = 0.009. Cervical length ≤11 mm had increased incidence of cervical dilation ≥1 cm on physical exam (30% vs 3%, odds ratio 12.29 (3.05-49.37) P < 0.001) with a negative predictive value of 97%. Patients with ≥1 cm dilation had increased preterm birth <37 weeks (75% vs 39%, P = 0.03) compared to those not dilated. Women with a CL ≤11 mm had increased preterm birth <37 weeks (77% vs 31%, P < 0.001), preterm birth <34 weeks (63% vs 22%, P < 0.001), and lower birthweight (1552 ± 1047 vs 2560 ± 1072 g, P < 0.001) compared to women with CL >11 mm.

CONCLUSIONS

Among singletons without prior preterm birth diagnosed with short cervix (≤25 mm), CL ≤11 mm may identify a subgroup of patients at high risk for asymptomatic cervical dilation and poor perinatal outcome. Physical exam should be considered and adjunctive preterm birth prevention measures should be studied in singletons with CL ≤11 mm.

HIV serostatus, viral load, and midtrimester cervical length in a Zambian prenatal cohort

OBJECTIVE

To evaluate whether maternal HIV serostatus and plasma viral load (VL) are associated with midtrimester cervical length (CL).

METHODS

The Zambian Preterm Birth Prevention Study (ZAPPS) is an ongoing prospective cohort that began enrolling in Lusaka in August 2015. Pregnant women undergo ultrasound to determine gestational age and return for CL measurement at 16-28 weeks. We evaluated crude and adjusted associations between dichotomous indicators and short cervix (≤2.5 cm) via logistic regression, and between VL and CL as a continuous variable via linear regression.

RESULTS

This analysis includes 1171 women enrolled between August 2015 and September 2017. Of 294 (25.1%) HIV-positive women, 275 (93.5%) had viral load performed close to CL measurement; of these, 148 (53.8%) had undetectable virus. Median CL was 3.6 cm (IQR 3.5-4.0) and was similar in HIV-infected (3.7 cm, IQR 3.5-4.0) versus uninfected (3.6 cm, IQR 3.5-4.0) participants (P=0.273). The odds of short CL were similar by HIV serostatus (OR 0.64; P=0.298) and detectable VL among those infected (OR 2.37, P=0.323). We observed no association between log VL and CL via linear regression (-0.12 cm; P=0.732).

CONCLUSION

We found no evidence of association between HIV infection and short CL.

A Quality Study to Explore Rationale for Pregnant Women to Decline Transvaginal Cervical Length Screening

OBJECTIVES

To identify patient rationale for pregnant women to decline transvaginal cervical length screening.

METHODS

Survey data from 511 women presenting for second-trimester anatomy and transvaginal cervical length sonography were collected during a 4-month period from September 2016 to January 2017. Each patient completed a medical questionnaire that includes demographic and obstetric history data and a survey to document their acceptance or declination of transvaginal cervical length screening.

RESULTS

Of the 511 women included in the study, 5.9% (n = 30) declined transvaginal cervical length screening. Demographic characteristics and risk factors for prematurity were similar between those who accepted and declined. The sonographer performing the study was significantly associated with declination of transvaginal cervical length screening (P < .001), with 4 of 13 sonographers accounting for 83.3% of all declinations. The most frequently reported reasons for declining the transvaginal cervical length screening were feeling that it was not needed (47%; n = 14) and not feeling prepared for the transvaginal sonography (27%; n = 8).

CONCLUSION

The findings of this study indicate that the sonographer performing transvaginal cervical length screening may be associated with declination. The most common reasons patients cited for declining included not feeling that the study was needed and not feeling prepared for the procedure. Increased sonographer education and sonographer use of a scripted approach when discussing the procedure with patients may improve patient acceptance.

A soft cervix, categorized by shear-wave elastography, in women with short or with normal cervical length at 18-24 weeks is associated with a higher prevalence of spontaneous preterm delivery

OBJECTIVE

To determine whether a soft cervix identified by shear-wave elastography between 18 and 24 weeks of gestation is associated with increased frequency of spontaneous preterm delivery (sPTD).

MATERIALS AND METHODS

This prospective cohort study included 628 consecutive women with a singleton pregnancy. Cervical length (mm) and softness [shear-wave speed: (SWS) meters per second (m/s)] of the internal cervical os were measured at 18-24 weeks of gestation. Frequency of sPTD <37 (sPTD<37) and <34 (sPTD<34) weeks of gestation was compared among women with and without a short (≤25 mm) and/or a soft cervix (SWS <25th percentile).

RESULTS

There were 31/628 (4.9%) sPTD<37 and 12/628 (1.9%) sPTD<34 deliveries. The combination of a soft and a short cervix increased the risk of sPTD<37 by 18-fold [relative risk (RR) 18.0 (95% confidence interval [CI], 7.7-43.9); P<0.0001] and the risk of sPTD<34 by 120-fold [RR 120.0 (95% CI 12.3-1009.9); P<0.0001] compared to women with normal cervical length. A soft-only cervix increased the risk of sPTD<37 by 4.5-fold [RR 4.5 (95% CI 2.1-9.8); P=0.0002] and of sPTD<34 by 21-fold [RR 21.0 (95% CI 2.6-169.3); P=0.0003] compared to a non-soft cervix.

CONCLUSIONS

A soft cervix at 18-24 weeks of gestation increases the risk of sPTD <37 and <34 weeks of gestation independently of cervical length.

Vaginal progesterone is as effective as cervical cerclage to prevent preterm birth in women with a singleton gestation, previous spontaneous preterm birth, and a short cervix: updated indirect comparison meta-analysis

BACKGROUND

An indirect comparison meta-analysis published in 2013 reported that both vaginal progesterone and cerclage are equally efficacious for preventing preterm birth and adverse perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a sonographic short cervix. The efficacy of vaginal progesterone has been challenged after publication of the OPPTIMUM study. However, this has been resolved by an individual patient-data meta-analysis (Am J Obstet Gynecol. 2018;218:161-180).

OBJECTIVE

To compare the efficacy of vaginal progesterone and cerclage in preventing preterm birth and adverse perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a midtrimester sonographic short cervix.

DATA SOURCES

MEDLINE, EMBASE, LILACS, and CINAHL (from their inception to March 2018); Cochrane databases, bibliographies, and conference proceedings.

STUDY ELIGIBILITY CRITERIA

Randomized controlled trials comparing vaginal progesterone to placebo/no treatment or cerclage to no cerclage in women with a singleton gestation, previous spontaneous preterm birth, and a sonographic cervical length <25 mm.

STUDY APPRAISAL AND SYNTHESIS METHODS

Updated systematic review and adjusted indirect comparison meta-analysis of vaginal progesterone vs cerclage using placebo/no cerclage as the common comparator. The primary outcomes were preterm birth <35 weeks of gestation and perinatal mortality. Pooled relative risks (RRs) with 95% confidence intervals were calculated.

RESULTS

Five trials comparing vaginal progesterone vs placebo (265 women) and 5 comparing cerclage vs no cerclage (504 women) were included. Vaginal progesterone, compared to placebo, significantly reduced the risk of preterm birth <35 and <32 weeks of gestation, composite perinatal morbidity/mortality, neonatal sepsis, composite neonatal morbidity, and admission to the neonatal intensive care unit (RRs from 0.29 to 0.68). Cerclage, compared to no cerclage, significantly decreased the risk of preterm birth <37, <35, <32, and <28 weeks of gestation, composite perinatal morbidity/mortality, and birthweight <1500 g (RRs from 0.64 to 0.70). Adjusted indirect comparison meta-analyses did not show statistically significant differences between vaginal progesterone and cerclage in the reduction of preterm birth or adverse perinatal outcomes.

CONCLUSION

Vaginal progesterone and cerclage are equally effective for preventing preterm birth and improving perinatal outcomes in women with a singleton gestation, previous spontaneous preterm birth, and a midtrimester sonographic short cervix. The choice of treatment will depend on adverse events and cost-effectiveness of interventions and patient/physician's preferences.

Quantitative analysis of cervical texture by ultrasound in mid-pregnancy and association with spontaneous preterm birth

OBJECTIVE

New tools are required to improve the identification of women who are at increased risk for spontaneous preterm birth (sPTB). Quantitative analysis of tissue texture on ultrasound has been used to extract robust features from the ultrasound image to detect subtle changes in its microstructure. This may be applied to the cervix. The aim of this study was to determine if there is an association between quantitative analysis of cervical texture (CTx) on mid-trimester ultrasound and sPTB < 37 + 0 weeks' gestation.

METHODS

This was a single-center nested case-control study of a prospective cohort of 677 consecutive women with singleton pregnancy assessed between 19 + 0 and 24 + 6 weeks' gestation. Women at increased risk for sPTB were included unless they received treatment to prevent sPTB. Women who delivered < 37 + 0 weeks (sPTB) were considered as cases and were matched in a 1: 10 ratio with randomly selected contemporary controls who delivered at term. For each woman, one ultrasound image of the cervix was obtained for which quality was assessed, cervical length (CL) measured offline and a region of interest in the midportion of the anterior cervical lip delineated for use in local binary patterns analysis of CTx. A learning algorithm was developed to obtain the combination of CTx features best associated with sPTB based on feature transformation and discriminant analysis regression. The ability of the learning algorithm to predict sPTB was evaluated using a leave-one-out cross-validation technique, which produced a CTx-based score for each participant. Receiver-operating characteristics (ROC) curves were produced and sensitivity, specificity, and positive and negative likelihood ratios were calculated for the optimal cut-off based on the ROC curve. The results were compared with those obtained for CL. Investigators studying the images were blinded to pregnancy outcome at all times.

RESULTS

Images from 310 women (27 cases and 283 controls) were of sufficient quality and included in the study. Median CTx-based score was significantly lower in cases compared with controls (-1.01 vs -0.07, P ≤ 0.0001). CTx-based score maintained its significant association with sPTB after adjusting for possible confounders (history of sPTB, conization or Müllerian malformation, and CL < 25 mm). CTx-based score was a better predictor of sPTB (AUC, 0.77; 95% CI, 0.66-0.87) than was CL (AUC, 0.60; 95% CI, 0.47-0.72) (P = 0.03). Median CL was similar for cases and controls (37.7 vs 38.6 mm, P = 0.26), although cases were more likely to have CL < 25 mm (18.5% vs 0.4%, P < 0.001).

CONCLUSION

Quantitative analysis of CTx enables the extraction of information relevant to sPTB from ultrasound images to generate a CTx-based score that is associated independently with sPTB. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Effect of age and cone dimensions on cervical regeneration: an Italian multicentric prospective observational study

OBJECTIVES

To evaluate cervical regeneration at 6 months following excisional treatment for high-grade cervical intraepithelial neoplasia (CIN), and to investigate the effect of cone dimensions, age of patients and technique of excision on the efficacy of the regeneration process.

DESIGN

Prospective observational multicentric study.

SETTING

Three tertiary care and research centres.

PARTICIPANTS

Among the 197 eligible women of childbearing age, older than 25 years of age, undergoing for the first time a loop electrosurgical excision procedure or carbon dioxide laser cervical excision for a high-grade CIN at the colposcopy-directed cervical punch biopsy, and with a final diagnosis of high-grade CIN, 165 completed the 6-month follow-up and were included in the analysis.

PRIMARY OUTCOME MEASURES

The cervical length and volume regeneration (%) after 6 months from procedure were determined by three-dimensional ultrasound, and the correlation of regeneration with cone dimensions, age and excision technique was evaluated.

RESULTS

The mean±SD cervical length regeneration at 6 months was 89.5%±6.3% and the mean±SD cervical volume regeneration was 86.3%±13.2%. At the multivariate analysis, a significant and independent inverse correlation between excised cone length and cervical regeneration emerged (r=-0.39, P<0.001). A significantly negative trend in length regeneration at 6 months from procedure with an increasing class of cone length was found (P<0.001). No significant association was found in relation with patient age at the time of procedure or with the technique of excision.

CONCLUSIONS

Cervical length regeneration at 6 months from excisional treatments is negatively affected by an increasing cone length but not from the age of the patient or the technique of excision. While still achieving equal clinical efficacy, it is crucial to contain cone dimensions, in order to favour a greater length regeneration, reducing the cervical harm and the potential future obstetric complications.

Vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix: a meta-analysis of individual patient data

BACKGROUND

The efficacy of vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix has been questioned after publication of the OPPTIMUM study.

OBJECTIVE

To determine whether vaginal progesterone prevents preterm birth and improves perinatal outcomes in asymptomatic women with a singleton gestation and a midtrimester sonographic short cervix.

STUDY DESIGN

We searched MEDLINE, EMBASE, LILACS, and CINAHL (from their inception to September 2017); Cochrane databases; bibliographies; and conference proceedings for randomized controlled trials comparing vaginal progesterone vs placebo/no treatment in women with a singleton gestation and a midtrimester sonographic cervical length ≤25 mm. This was a systematic review and meta-analysis of individual patient data. The primary outcome was preterm birth <33 weeks of gestation. Secondary outcomes included adverse perinatal outcomes and neurodevelopmental and health outcomes at 2 years of age. Individual patient data were analyzed using a 2-stage approach. Pooled relative risks with 95% confidence intervals were calculated. Quality of evidence was assessed using the GRADE methodology.

RESULTS

Data were available from 974 women (498 allocated to vaginal progesterone, 476 allocated to placebo) with a cervical length ≤25 mm participating in 5 high-quality trials. Vaginal progesterone was associated with a significant reduction in the risk of preterm birth <33 weeks of gestation (relative risk, 0.62; 95% confidence interval, 0.47-0.81; P = .0006; high-quality evidence). Moreover, vaginal progesterone significantly decreased the risk of preterm birth <36, <35, <34, <32, <30, and <28 weeks of gestation; spontaneous preterm birth <33 and <34 weeks of gestation; respiratory distress syndrome; composite neonatal morbidity and mortality; birthweight <1500 and <2500 g; and admission to the neonatal intensive care unit (relative risks from 0.47-0.82; high-quality evidence for all). There were 7 (1.4%) neonatal deaths in the vaginal progesterone group and 15 (3.2%) in the placebo group (relative risk, 0.44; 95% confidence interval, 0.18-1.07; P = .07; low-quality evidence). Maternal adverse events, congenital anomalies, and adverse neurodevelopmental and health outcomes at 2 years of age did not differ between groups.

CONCLUSION

Vaginal progesterone decreases the risk of preterm birth and improves perinatal outcomes in singleton gestations with a midtrimester sonographic short cervix, without any demonstrable deleterious effects on childhood neurodevelopment.

Vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix: a meta-analysis of individual patient data

BACKGROUND

The efficacy of vaginal progesterone for preventing preterm birth and adverse perinatal outcomes in singleton gestations with a short cervix has been questioned after publication of the OPPTIMUM study.

OBJECTIVE

To determine whether vaginal progesterone prevents preterm birth and improves perinatal outcomes in asymptomatic women with a singleton gestation and a midtrimester sonographic short cervix.

STUDY DESIGN

We searched MEDLINE, EMBASE, LILACS, and CINAHL (from their inception to September 2017); Cochrane databases; bibliographies; and conference proceedings for randomized controlled trials comparing vaginal progesterone vs placebo/no treatment in women with a singleton gestation and a midtrimester sonographic cervical length ≤25 mm. This was a systematic review and meta-analysis of individual patient data. The primary outcome was preterm birth <33 weeks of gestation. Secondary outcomes included adverse perinatal outcomes and neurodevelopmental and health outcomes at 2 years of age. Individual patient data were analyzed using a 2-stage approach. Pooled relative risks with 95% confidence intervals were calculated. Quality of evidence was assessed using the GRADE methodology.

RESULTS

Data were available from 974 women (498 allocated to vaginal progesterone, 476 allocated to placebo) with a cervical length ≤25 mm participating in 5 high-quality trials. Vaginal progesterone was associated with a significant reduction in the risk of preterm birth <33 weeks of gestation (relative risk, 0.62; 95% confidence interval, 0.47-0.81; P = .0006; high-quality evidence). Moreover, vaginal progesterone significantly decreased the risk of preterm birth <36, <35, <34, <32, <30, and <28 weeks of gestation; spontaneous preterm birth <33 and <34 weeks of gestation; respiratory distress syndrome; composite neonatal morbidity and mortality; birthweight <1500 and <2500 g; and admission to the neonatal intensive care unit (relative risks from 0.47-0.82; high-quality evidence for all). There were 7 (1.4%) neonatal deaths in the vaginal progesterone group and 15 (3.2%) in the placebo group (relative risk, 0.44; 95% confidence interval, 0.18-1.07; P = .07; low-quality evidence). Maternal adverse events, congenital anomalies, and adverse neurodevelopmental and health outcomes at 2 years of age did not differ between groups.

CONCLUSION

Vaginal progesterone decreases the risk of preterm birth and improves perinatal outcomes in singleton gestations with a midtrimester sonographic short cervix, without any demonstrable deleterious effects on childhood neurodevelopment.

Decrease in the incidence of threatened preterm labor after implementation of transvaginal ultrasound cervical length universal screening

BACKGROUND

It is unknown if universal second-trimester transvaginal ultrasound (TVU) cervical length (CL) screening in asymptomatic women with singleton gestations and no prior spontaneous preterm birth (SPTB) affects the incidence of symptoms of preterm labor (PTL) later in pregnancy.

OBJECTIVE

To evaluate the incidence of threatened PTL before and after the implementation of universal second trimester TVU CL screening.

STUDY DESIGN

This was a retrospective cohort study of all consecutive singleton gestations without prior SPTB presenting to obstetric triage for threatened PTL between 23 0/7 and 33 6/7 week in 2011 (1 January-31 December), and in 2014 (1 January-31 December) at Thomas Jefferson University Hospital (TJU) (Philadelphia, PA). These 2 years were chosen as a new protocol for universal TVU CL screening was started on 1 January 2012. This protocol involved one measurement of TVU CL in all singleton gestations without a prior SPTB at 18 0/7 - 23 6/7 week, the time of the "anatomy" scan. Women with prior SPTB were excluded from this study. The primary outcome included the incidence of threatened PTL, defined as the number of women with singleton gestations without prior SPTB who presented with threatened PTL to our labor and delivery (L&D) triage unit annually, divided by the total number of annual deliveries of women with singleton gestation without prior SPTB. Secondary outcomes were the incidence of PTL, defined as the number of women with singleton gestations without prior SPTB admitted for PTL annually divided by the total number of annual deliveries of women with singleton gestation and without prior SPTB; and length of stay in the hospital. We aimed to compare primary and secondary outcome in the "2011" versus the "2014" group.

RESULTS

In 2011, there were a total of 1745 deliveries at TJU, of which 1550 (88.8%) were singletons without prior SPTB. In 2014, there were a total of 1924 deliveries at TJU, 1751 (91.0%) were singletons without prior SPTB who were offered universal TVU CL screening. One hundred and seventy-two women with singletons without prior SPTB presented in L&D triage unit in 2011; and 118 women with singletons without prior SPTB presented in L&D triage unit in 2014. There were significant decreases in the incidence of threatened PTL from 11.1% (172/1550) in 2011 to 6.7% (118/1751) in 2014 (p < .001), as well as in the rate of admission for PTL from 2.3% (35/1550) to 1.4% (24/1751), respectively (p = .04). Length of stay was not significantly different between the two groups.

CONCLUSION

The introduction of a universal TVU CL screening program in women with singleton gestations without a history of SPTB is associated with a reduction in the frequency of threatened PTL and admission for PTL. Key Message The introduction of a second trimester universal transvaginal ultrasound (TVU) cervical length (CL) screening program in women without a history of spontaneous preterm birth (SPTB) is associated with a reduction in the incidence of threatened preterm labor (PTL) and admission for PTL.

Predicting preterm birth: Cervical length and fetal fibronectin

Spontaneous preterm birth remains the leading cause of neonatal morbidity and mortality worldwide, and accounts for a significant global health burden. Several obstetric strategies to screen for spontaneous preterm delivery, such as cervical length and fetal fibronectin measurement, have emerged. However, the effectiveness of these strategies relies on their ability to accurately predict those pregnancies at increased risk for spontaneous preterm birth (SPTB). Transvaginal cervical shortening is predictive of preterm birth and when coupled with appropriate preterm birth prevention strategies, has been associated with reductions in SPTB in asymptomatic women with a singleton gestation. The use of qualitative fetal fibronectin may be useful in conjunction with cervical length assessment in women with acute preterm labor symptoms, but data supporting its clinical utility remain limited. As both cervical length and qualitative fetal fibronectin have limited capacity to predict preterm birth, further studies are needed to investigate other potential screening modalities.

Recent advances in the prevention of preterm birth

Preterm birth (PTB) remains a major obstetric healthcare problem and a significant contributor to perinatal morbidity, mortality, and long-term disability. Over the past few decades, the perinatal outcomes of preterm neonates have improved markedly through research and advances in neonatal care, whereas rates of spontaneous PTB have essentially remained static. However, research into causal pathways and new diagnostic and treatment modalities is now bearing fruit and translational initiatives are beginning to impact upon PTB rates. Successful PTB prevention requires a multifaceted approach, combining public health and educational programs, lifestyle modification, access to/optimisation of obstetric healthcare, effective prediction and diagnostic modalities, and the application of effective, targeted interventions. Progress has been made in some of these areas, although there remain areas of controversy and uncertainty. Attention is now being directed to areas where greater gains can be achieved. In this mini-review, we will briefly and selectively review a range of PTB prevention strategies and initiatives where progress has been made and where exciting opportunities await exploitation, evaluation, and implementation.

Second trimester cervical length measurement for prediction spontaneous preterm birth in an unselected risk population

OBJECTIVE

To assess the predictive capacity of cervical length (CL) measurement underwent during the second trimester ultrasound for prediction preterm birth <32, 34, and 37 weeks of gestation in an unselected risk population.

METHODS

A retrospective cohort study was performed with 751 singleton pregnancies between 20 and 24+6 weeks of gestation. The CL measurement (mm) using the transvaginal route was obtained in a sagittal view and the calipers positioned to measure the linear distance between the triangular area of echodensity at the external os and the internal os. To compare the preterm (<37 weeks) and term births (≥37 weeks), we used unpaired t test. We assessed whether the CL measurement was dependent of gestational age by performing a linear regression and assessing the coefficient of determination (R2). We additionally assessed the accuracy of CL measurement to predict preterm birth by assessing the area under receiver operating characteristics curves with its respective confidence intervals (CIs) 95%.

RESULTS

Preterm birth <37 weeks was found in 13.6% (102/751) of pregnant women. Short cervix (≤25 mm) was found in 2.7% (20/751) of pregnancies. Only 30% (6/20) of pregnant women with short cervix have used progesterone to prevent preterm birth. There was a weak correlation between CL measurement and gestational age at delivery (R2=0.01, P=0.002). Receiver operating characteristics curve analysis of the ability of CL measurement to predict preterm birth <32, 34, and 37 weeks, showed an area under the curve of 0.693 (95% CI, 0.512 to 0.874), 0.472 (95% CI, 0.353 to 0.591), 0.490 (95% CI, 0.426 to 0.555), respectively.

CONCLUSION

There was a weak correlation between CL measurement and gestational age at delivery. In an unselected population, CL measurement screening at 20 to 24+6 weeks of gestation does not seem to be a good predictor of preterm birth.

Assessment of Transvaginal Ultrasound Cervical Length Image Quality

OBJECTIVE

To use data from the Cervical Length Education and Review program to evaluate the quality of transvaginal cervical length ultrasonography by trained imagers (ie, ultrasonographers, radiologists, perinatologists).

METHODS

This is a retrospective observational study of data from the Cervical Length Education and Review program. Candidates underwent an online lecture series, examination, and submitted a batch of images for review. For a candidate's batch of images to pass, all images must meet at least seven of the nine criteria assessed, the overall batch score needs to be 80% or greater, correct caliper placement must be met for all images, and the same criterion cannot be consistently missed. We also examined a subset of these criteria-appropriate image acquisitions, defined as an image that demonstrated both internal and external os and visualization of the entire endocervical canal. Primary outcome was the overall initial candidate pass rate; secondary outcomes included distribution of criteria missed in images and percentage of images that was inadequately acquired.

RESULTS

Six hundred eighty-seven candidates submitted 3,748 images between June 10, 2012, and August 18, 2016. Eighty-five percent of candidates were ultrasonographers. Of the 687 initial batches submitted, 105 (15%) did not pass. Eight hundred thirty-seven images (22%) of all images failed at least one criterion; the most common image deficiencies were in "anterior width of cervix equals the posterior width" (33%), "failure to visualize" the internal or external os (29%), "cervix occupies 75% of image and bladder area visible" (33%), and incorrect caliper placement (24%). Two hundred fifty-six (7%) of all images failed to meet our criteria for adequate image acquisition.

CONCLUSION

Fifteen percent of trained imagers failed to obtain appropriate cervical length imaging. This highlights the importance of a standardized cervical length training and certification program.

Reducing preterm birth by a statewide multifaceted program: an implementation study

BACKGROUND

A comprehensive preterm birth prevention program was introduced in the state of Western Australia encompassing new clinical guidelines, an outreach program for health care practitioners, a public health program for women and their families based on print and social media, and a new clinic at the state's sole tertiary level perinatal center for referral of those pregnant women at highest risk. The initiative had the single aim of safely lowering the rate of preterm birth.

OBJECTIVE

The objective of the study was to evaluate the outcomes of the initiative on the rates of preterm birth both statewide and in the single tertiary level perinatal referral center.

STUDY DESIGN

This was a prospective population-based cohort study of perinatal outcomes before and after 1 full year of implementation of the preterm birth prevention program.

RESULTS

In the state overall, the rate of singleton preterm birth was reduced by 7.6% and was lower than in any of the preceding 6 years. This reduction amounted to 196 cases relative to the year before the introduction of the initiative and the effect extended from the 28-31 week gestational age group onward. Within the tertiary level center, the rate of preterm birth in 2015 was also significantly lower than in the preceding years.

CONCLUSION

A comprehensive and multifaceted preterm birth prevention program aimed at both health care practitioners and the general public, operating within the environment of a government-funded universal health care system can significantly lower the rate of early birth. Further research is now required to increase the effect and to determine the relative contributions of each of the interventions.