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

Different interventions to prevent preterm birth in pregnant women with cervical shortening during pregnancy: a protocol for a network meta-analysis

INTRODUCTION

Premature birth is the leading cause of neonatal mortality. Cervical length shortening during pregnancy serves as the gold standard for predicting preterm birth. Although several interventions have been applied to reduce the incidence of preterm birth in short cervix pregnant women, the optimal intervention in clinical practice remains controversial. The aim of this study is to conduct a network meta-analysis to explore the optimal intervention for preventing preterm birth among pregnant women with a short cervix.

METHODS AND ANALYSIS

We will search electronic information databases including PubMed, Embase Ovid, Cochrane Library Ovid, Wanfang Data, China Science and Technology Journal Database(VIP) and clinical trial registry websites (US Clinical Trials Registry and China Clinical Trials Registry) until 1 January 2024. Randomised controlled trials (RCTs) comparing two or more interventions to prevent preterm birth in short cervix pregnant women will be included. The primary outcomes are preterm birth rate at <37 weeks and the composite neonatal adverse outcome, secondary outcomes include spontaneous preterm birth rate at <37 weeks, preterm birth rate at <34 weeks, spontaneous preterm birth rate at <34 weeks, week of gestation, birth weight of the newborn, perinatal mortality and neonatal admission rate. Risk of bias 2.0 (ROB 2.0） will be used to assess the risk of bias in the RCT, and the Confidence in Network Meta-Analysis software will be used to assess the certainty of the generated evidence. The network meta-analysis will be conducted using the gemtc package in R 4.2.2. Two investigators independently performed article screening, data extraction and quality assessment. In addition, subgroup analyses and sensitivity analyses will be used to assess the robustness of the findings.

ETHICS AND DISSEMINATION

Ethical considerations will not be required. Results will be published in a peer-review journal.

PROSPERO REGISTRATION NUMBER

CRD42022315200.

Uterocervical angle in predicting spontaneous preterm birth: a systematic review and meta-analysis

OBJECTIVE

This study aimed to compare the uterocervical angles in term and spontaneous preterm birth cohorts and to compare the test characteristics of the uterocervical angle and cervical length in the prediction of spontaneous preterm birth.

DATA SOURCES

A systematic search of published literature from January 1, 1945, to May 15, 2022, was performed using the following databases: PubMed, Cochrane Central Register of Controlled Trials, Embase, World Health Organization International Clinical Trials Registry Platform, Web of Science, and ClinicalTrials.gov. The search was not restricted. The references of all relevant articles were reviewed.

STUDY ELIGIBILITY CRITERIA

Randomized control trials, nonrandomized control trials, and observational studies were evaluated for primary comparisons. Included studies compared the uterocervical angles in term and spontaneous preterm birth cohorts and compared the uterocervical angle with cervical length in the prediction of spontaneous preterm birth.

METHODS

Of note, 2 researchers independently selected studies and evaluated the risk of bias with the Newcastle-Ottawa Scale for cohort and case-control studies. Mean differences and odds ratios were calculated using a random effects model for inclusion and methodological quality. The primary outcomes were uterocervical angle and successful prediction of spontaneous preterm birth. Moreover, posthoc analysis comparing the uterocervical angle and cervical length together was performed.

RESULTS

A total of 15 cohort studies with 6218 patients were included. The uterocervical angle was larger in the spontaneous preterm birth cohorts (mean difference, 13.76; 95% confidence interval, 10.61-16.91; P<.00001; I²=90%). Sensitivity and specificity analyses demonstrated lower sensitivities with cervical length alone and uterocervical angle plus cervical length than with uterocervical angle alone. Pooled sensitivities for uterocervical angle and cervical length alone were 0.70 (95% confidence interval, 0.66-0.73; I²=90%) and 0.46 (95% confidence interval, 0.42-0.49; I²=96%), respectively. Pooled specificities for uterocervical angle and cervical length were 0.67 (95% confidence interval, 0.66-0.68; I²=97%) and 0.90 (95% confidence interval, 0.89-0.91; I²=99%), respectively. The areas under the curve for uterocervical angle and cervical length were 0.77 and 0.82, respectively.

CONCLUSION

Uterocervical angle alone or with cervical length was not superior to cervical length alone in predicting spontaneous preterm birth.

A nomogram to optimize the timing of antenatal corticosteroids in threatened preterm delivery

BACKGROUND

Recent observational studies reported a high rate of suboptimal use of antenatal corticosteroids (too anticipated or retrospectively not indicated) for women at risk of preterm delivery despite a recommended use within 7 days before delivery.

OBJECTIVE

This study aimed to elaborate a nomogram aiming at optimizing the timing of administration of antenatal corticosteroids in case of threatened preterm labor, asymptomatic short cervix, or uterine contractions.

STUDY DESIGN

This was an observational retrospective study conducted in a tertiary hospital. All women between 24 and 34 weeks of gestation who received corticosteroids during hospitalization for threatened preterm delivery, asymptomatic short cervix, or uterine contractions requiring tocolysis between 2015 and 2019 were included. Clinical, biological, and sonographic data of women were used to construct logistic regression models for predicting delivery within 7 days. The model was validated on an independent series of women hospitalized in 2020.

RESULTS

Among the 1343 women included in this study, the risk factors independently associated with a delivery within 7 days in multivariate analysis were vaginal bleeding (odds ratio, 14.47; 95% confidence interval, 7.81-26.81; P<.001); need for a second-line tocolysis, such as atosiban (odds ratio, 5.66; 95% confidence interval, 3.39-9.45; P<.001); C-reactive protein level (per 1 mg/L increase; odds ratio, 1.03; 95% confidence interval, 1.02-1.04; P<.001); cervical length (per 1 mm increase; odds ratio, 0.84; 95% confidence interval, 0.82-0.87; P<.001); uterine scar (odds ratio, 2.98; 95% confidence interval, 1.33-6.65; P=.008), and gestational age at admission (per week of amenorrhea increase; odds ratio, 1.10; 95% confidence interval, 1.00-1.20; P=.041). Based on these results, a nomogram was developed that, in retrospect, would have allowed physicians to avoid or delay antenatal corticosteroids in 57% of cases in our population. The discrimination of the predictive model was good when applied to the validation set of 232 women hospitalized in 2020. It would have enabled physicians to avoid or delay antenatal corticosteroids in 52% of cases.

CONCLUSION

This study developed a simple use, accurate prognostic score to identify women at risk of delivery within 7 days in cases of threatened preterm delivery, asymptomatic short cervix, or uterine contractions and thereby optimized the use of antenatal corticosteroids.