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

Estimates of avoided costs attributed to a short cervix screening program to prevent preterm birth from the perspective of the Unified Health System (SUS)

OBJECTIVE

To perform an economic cost analysis of the implementation of a short cervix screening program to reduce preterm birth in singleton pregnancies in a short-term time horizon.

METHODS

We performed a cost-benefit economic analysis using the P5 trial database, a randomized multicenter clinical trial for prevention of preterm birth. Data collection was conducted from July 2015 to March 2019 in 17 different Brazilian hospitals. We conducted a cost analysis for universal cervical screening in singleton pregnancies between 18 weeks and 22 weeks plus 6 days. In subjects with a cervical length ≤ 25 mm, the analysis incorporated the costs of administering 200 mg/day of vaginal progesterone prophylactically until 36 weeks gestation. These findings were subsequently compared with the economic implications of forgoing cervical screening. The time horizon comprised from birth to 10 weeks postpartum. The outcome was measured monetarily in Brazilian real (R$) from the perspective of the Unified Health System.

RESULTS

Among 7,844 women, 6.67% (523) had a cervix ≤ 25 mm. The cost of screening with transvaginal ultrasound and vaginal progesterone for prevention of births with < 34 weeks was estimated at R$ 383,711.36, while non-screening generated an estimated additional cost of R$ 446,501.69 (related to the 29 non-screened preterm deliveries). Thus, screening and prophylaxis would generate a final cost reduction of R$ 62,790.33, constituting a possible cost-benefit strategy.

CONCLUSION

Universal short cervix screening for preterm birth has lower costs compared to non-screening within a short-term time horizon, which suggests an interesting benefit-cost ratio. Future studies should consider the cost-effectiveness of prophylactic treatment using sensitivity analyses in different scenarios within the Brazilian health system, as well as analyses that consider the long-term costs associated with preterm births, to robustly justify the implementation of a short cervix screening program.

Association between cervical length and gestational age at birth in singleton pregnancies: a multicentric prospective cohort study in the Brazilian population

BACKGROUND

Short cervical length measured during the second trimester of pregnancy is an important risk factor for spontaneous preterm birth (sPTB). The aim of this study is to identify the association between mid-pregnancy cervical length (CL) and gestational age at birth in asymptomatic singleton pregnant women.

METHODS

This is a prospective cohort study involving singleton pregnant women who participated in the screening phase of a Brazilian multicenter randomized controlled trial (P5 trial) between July 2015 and March 2019. Transvaginal ultrasound to measure CL was performed from 18 to 22 + 6 weeks. Women with CL ≤ 30 mm received vaginal progesterone (200 mg/day) until 36 weeks' gestation. For this analysis we considered all women with CL ≤ 30 mm receiving progesterone and a random selection of women with CL > 30 mm, keeping the populational distribution of CL. We obtained prognostic effectiveness data (area under receive operating characteristic curve (AUC), sensitivity and specificity and estimated Kaplan-Meier curves for preterm birth using different CL cutoff points.

RESULTS

We report on 3139 women and identified a negative association between cervical length and sPTB. CL ≤ 25 mm was associated with sPTB < 28, sPTB < 34 and sPTB < 37 weeks, whereas a CL 25-30 mm was directly associated with late sPTB. CL by transvaginal ultrasound presented an AUC of 0.82 to predict sPTB < 28 weeks and 0.67 for sPTB < 34 weeks. Almost half of the sPTB occurred in nulliparous women and CL ≤ 30 mm was associated with sPTB at < 37 weeks (OR = 7.84; 95%CI = 5.5-11.1). The number needed to screen to detect one sPTB < 34 weeks in women with CL ≤ 25 mm is 121 and we estimated that 248 screening tests are necessary to prevent one sPTB < 34 weeks using progesterone prophylaxis.

CONCLUSIONS

CL measured by transvaginal ultrasound should be used to predict sPTB < 34 weeks. Women with CL ≤ 30 mm are at increased risk for late sPTB.

Evaluation of the effectiveness of foetal fibronectin as a predictor of preterm birth in symptomatic preterm labour women

BACKGROUND

The prediction of preterm birth (PTB) is important in the management of symptomatic preterm labour women. We evaluated the effectiveness of the foetal fibronectin (fFN) test for predicting PTB in symptomatic preterm labour women with consideration of physiologic changes in cervical length (CL) during pregnancy.

METHODS

This prospective study included 85 women with symptomatic preterm labour of a singleton pregnancy. Positive fFN was defined as a fFN level of > 50 ng/mL in cervicovaginal secretion, while a short CL was defined as that below 25th percentile at the corresponding gestational age. We evaluated effectiveness of the fFN test, CL, and the combination of these two tests, including sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), positive likelihood ratio (LR⁺), negative likelihood ratio (LR^-) to predict the PTB within 7 and 14 days of testing and PTB at < 34 and 37 weeks of gestation. We also present the odds ratios (ORs) of the test results, defining the women with both negative results as the reference group.

RESULTS

Of the 85 women, 31 (36.5%) showed a positive fFN and 44 (51.8%) had a short CL. PTB occurred within 7 and 14 days of testing and before 34 and 37 weeks of gestation in 17.6, 20.0, 23.5 and 49.4% of the women, respectively. The fFN and CL results showed low predictive effectiveness for the studied outcomes with LR⁺ (fFN, 1.5-1.9; CL, 1.0-1.5) and LR^- (fFN, 0.7; CL, 0.7-0.9). The combined use of fFN and CL could not improve these results (LR⁺, 1.4-2.3; LR^-, 0.7-0.9). However, the risk of PTB before 37 weeks was increased in women with positive fFN but not CL shortening compared to the reference group (odds ratio [OR], 3.8; 95% confidence interval [CI], 1.1-1.3). The risk of PTB before 34 weeks was increased in both positive fFN and CL compared to the reference group (OR, 8.1; 95% CI, 1.9-34.5).

CONCLUSION

Although, our approach could not improve the ability to predict PTB, it could identify women at risk for delivery before 34 or 37 weeks of gestation. Therefore, it could be used to manage women with symptomatic preterm labour.

Cervical cerclage, pessary, or vaginal progesterone in high-risk pregnant women with short cervix: a randomized feasibility study

Objective: To assess feasibility for a definitive randomized controlled trial (RCT) comparing three treatments for short cervix in a population at high risk for spontaneous preterm birth (sPTB) over a 1-year period.Design: Three arm, open label feasibility randomized clinical study.Methods: Women with singleton pregnancy with risk factors for sPTB (history of sPTB or prelabor premature rupture of membranes (PPROM) <34 weeks or significant cervical surgery), and short cervix on transvaginal ultrasound scan detected between 16⁺⁰ and 24⁺⁶ weeks gestation were randomized to receive either cervical cerclage, vaginal pessary, or vaginal progesterone 200 mg nocte. Pregnancy outcomes and treatment costs were collected from hospital records, NHS Reference costs, and British National Formulary costs.Main outcome measures: Feasibility targets were defined as (i) at least 55% of eligible women randomized; (ii) maximum 5% failure to adhere to the protocol per arm; (iii) maximum 5% loss to short-term follow-up.Results: Of 417 women screened between October 2015 and 2016, 25 (6%) were eligible for trial inclusion, of whom 18 (72%) agreed to participate at the rate 0.75 participants/site/month. Adherence to protocol was 100% in pessary and cerclage arms and 80% in vaginal progesterone arm (95% CI 24-100%). No participants were lost to follow up. Cost of interventions accounted for 6% (95% CI 2-10%) of overall health care expenditure.Conclusions: A definitive clinical trial comparing treatments for prevention of sPTB in high-risk women with short cervix is feasible but will be challenging due to small numbers of eligible participants.

Predicting the target genes of miRNAs in preterm via targetscore algorithm

Compared with normal neonates, preterm infants have an immature immune system which causes them to have a higher morbidity rate and even death. In order to reduce the mortality of newborns, we need to find the target genes which affect the preterm and understand their mechanism. It has been verified that microRNA (miRNA)-200 and miRNA-182 are closely related to the incidence of preterm. Therefore, it is significant to predict the target genes which are regulated by them for further understanding the mechanism of preterm. We chose the targetscore method for calculating the variational Bayesian-Gaussian mixture model (VB-GMM) as the target genes prediction method. It is designed for condition-specific target predictions and not limited to predict conserved genes, so the results are more accurate than previous sequence-based target prediction algorithms. In this study, our major contribution is to predict the target mRNAs of the chosen miRNAs with the gene expression profiles and a new method, which can effectively improve the accuracy of the prediction.

Associations of temporal changes in cervical length and lower uterine segment length with spontaneous preterm delivery risk: a prospective study of 727 Japanese women

PURPOSE

A prospective assessment of the risk of spontaneous preterm delivery (sPTD) by evaluating temporal changes in cervical measurements.

METHODS

We analyzed clinical variables, focusing on cervical length (CL) and lower uterine segment (LUS) length (LUSL) as measured by transvaginal ultrasonography in 727 pregnant Japanese women.

RESULTS

In women undergoing term deliveries, CL increased from gestational week (GW) 8-25. In contrast, the combination of CL and LUSL (ComL for "combined length") gradually decreased and sole LUSL became almost 0 mm by GW 25. Univariate logistic regression analysis suggested that a history of PTD was a risk factor for sPTD. CL, LUSL, and ComL were not significant predictors of sPTD.

CONCLUSION

To assess the risk of sPTD in the second trimester, it is not necessary to distinguish the cervix from the LUS.