A stepwise approach for the management of short cervix: time to evolve beyond progesterone treatment in the presence of progressive cervical shortening

Cervical elastography in predicting spontaneous preterm birth in singleton pregnancy with a short cervix receiving progesterone treatment at 18 to 24 weeks' gestation

BACKGROUND

A short cervix in the second trimester is known to increase the risk of preterm birth, which can be reduced with the administration of vaginal progesterone. However, some studies have suggested that a significant number of cases still experience preterm birth despite progesterone treatment.

OBJECTIVE

This study was aimed to investigate the potential value of transvaginal cervical elasticity measured by E-Cervix as a predictor for spontaneous preterm birth (sPTB) in singleton pregnancies receiving progesterone treatment for a short cervix (CL ≤ 2.5 cm) diagnosed at 18 to 24 weeks' gestation.

STUDY DESIGN

This prospective study was conducted at a single center premature high-risk clinic from January 2020 to July 2022. Singleton pregnancies with a short cervix at 18 to 24 weeks' gestation were enrolled. Cervical elastography using E-Cervix was performed, and maternal and neonatal demographic characteristics, cervical length (CL), elasticity contrast index (ECI), cervical hardness ratio, mean internal os strain (IOS), and mean external os strain (EOS) were compared before and after progesterone treatment in sPTB and term birth groups. Multivariate logistic regression was used to analyze the association between elasticity parameters and spontaneous preterm birth. The screening performance of CL and optimal cervical elasticity parameters in predicting sPTB was evaluated using receiver-operating characteristic (ROC) curve analysis.

RESULTS

A total of 228 singleton pregnant women were included in the study, among which 26 (11.4%) had sPTB. There were no significant differences in maternal characteristics and gestational age at enrollment between women with and without sPTB. At the start of progesterone treatment, there were no significant differences in cervical elasticity parameters between the two groups. After two weeks of progesterone treatment, women who had sPTB showed significantly higher levels of ECI, IOS, EOS (p = 0.0108, 0.0001, 0.016), and lower hardness ratio (p = 0.011) compared to those who had a full-term birth. Cervical length did not show significant differences between the two groups, regardless of whether progesterone treatment was administered before or after. Among the post-treatment cervical elasticity parameters, IOS and EOS were associated with a 3.38-fold and 2.29-fold increase in the risk of sPTB before 37 weeks (p = 0.032, 0.047, respectively). The AUROC of the combined model including CL, IOS, and EOS (0.761, 95% CI0.589-0.833) was significantly higher than the AUROC of CL alone (0.618, 95% CI 0.359-0.876). At a fixed false-positive of 13%, the addition of IOS and EOS in the CL model increased sensitivity from 34.6% to 57.6%, PPV from 25.7% to 36.5%, and NPV from 91.1% to 94.1%.

CONCLUSION

When assessing the risk of sPTB in singleton pregnancies with a short cervix receiving progesterone therapy, relying solely on cervical length is insufficient. It is crucial to also evaluate cervical stiffness, particularly the strain of the internal and external os, using cervical elastography.

Reduction in cervical length after vaginal progesterone in women with short cervix is significantly associated with preterm delivery at ≤ 34 weeks and < 37 weeks of gestation

OBJECTIVE

To evaluate the association between changes in cervical length (CL) after vaginal progesterone treatment and preterm delivery (PTD).

METHODS

This was a retrospective cohort study that included 197 singleton pregnancies without (n = 178) and with (n = 19) a history of PTD which were found to have a short cervix (≤ 25 mm) between 18 + 0 and 23 + 6 weeks' gestation with a follow-up transvaginal CL measurement taken at least 1 week after vaginal progesterone treatment started. Receiver-operating-characteristics (ROC)-curve analysis was performed and three CL shortening patterns were evaluated: (1) ≥ 10% reduction; (2) ≥ 20% reduction; and (3) ≥ 5 mm reduction relative to the first CL measurement. The predictive performance of each CL reduction cut-off and its association with PTD ≤ 34 weeks and PTD < 37 weeks were evaluated.

RESULTS

Overall, the rate of PTD ≤ 34 weeks was 16.8% (33/197) and that of PTD < 37 weeks was 36.5% (72/197). The area under the ROC curve of cervical shortening expressed in % for predicting PTD ≤ 34 weeks and PTD < 37 weeks was 0.703 and 0.608, respectively. Cervical shortening was observed in 60/197 (30.5%) patients, with 49/60 (81.7%) women showing ≥ 10% reduction, 32/60 (53.3%) ≥ 20% reduction and 27/60 (45.0%) ≥ 5 mm reduction in CL. Sensitivity and specificity for PTD ≤ 34 weeks were, respectively, 48.5% and 79.9% for ≥ 10% reduction; 36.4% and 87.8% for ≥ 20% reduction; and 27.3% and 89.0% for ≥ 5 mm reduction in CL. For PTD < 37 weeks, sensitivity and specificity were, respectively, 36.1% and 81.6% for ≥ 10% reduction; 27.8% and 90.4% for ≥ 20% reduction; and 20.8% and 90.4% for ≥ 5 mm reduction in CL. The highest positive likelihood ratios for PTD ≤ 34 and < 37 weeks were for ≥ 20% CL reduction (2.98 (95% CI, 1.62-5.49) and 2.89 (95% CI, 1.52-5.57), respectively). Despite significant differences in sensitivity among the different cut-offs for cervical shortening, favoring the ≥ 10% reduction cut-off, a reduction of ≥ 20% in CL showed the strongest association with PTD ≤ 34 weeks (odds ratio (OR), 4.11 (95% CI, 1.75-9.62)) and < 37 weeks (OR, 3.62 (95% CI, 1.65-7.96)), as compared with a less pronounced reduction in CL.

CONCLUSIONS

In women with a short cervix treated with vaginal progesterone, a reduction in CL on a subsequent ultrasound scan can predict PTD ≤ 34 and < 37 weeks. A ≥ 20% reduction in CL had the highest positive likelihood ratio and strongest association with PTD ≤ 34 and < 37 weeks compared with ≥ 10% or ≥ 5 mm reduction. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Cervical Cerclage vs. Pessary in Women with a Short Cervix on Ultrasound

PURPOSE

In the present study we sought to compare the efficacy of cervical pessary to that of cerclage in terms of reducing preterm birth rates among women with a short (<25 mm) or ultra-short (<15 and <10 mm) cervix during the ultrasonographic second-trimester assessment.

METHOD

We retrospectively searched the hospital records for singleton pregnancies diagnosed with cervical insufficiency during the second trimester of pregnancy. The McDonald cerclage using a 5mm Mersilene tape was used in all women. An Arabin pessary was used uniformly. In all cases 80 mg of vaginal progesterone gel were administered daily until 37 weeks of gestation.

RESULTS

Overall, 294 women (124 (42.2%) with a McDonald cerclage and 170 (57.8%) with placement of an Arabin pessary) were selected for analysis. Preterm birth rates <37 weeks were similar in both groups (C: 30/122 vs. P: 35:165, p=.581) as well as PTB <34 weeks (C: 16/122 vs. 15/150, p=.278). Admission to the NICU and need for CPAP were more prevalent in the cerclage group (p<.001). Analysis of cases with a cervix <15 mm and <10 mm indicated that preterm birth rates remained equal among the groups, while an increased risk of NICU admission was seen in cases with a cervical length <10 mm that were treated with cerclage.

DISCUSSION AND CONCLUSION

Cervical pessary may be an alternative to cervical cerclage for women with second-trimester cervical shortening and its effect may persist even among cases with an ultra-short cervix. Future randomized trials are needed to ascertain these findings.

Combined vaginal progesterone and cervical cerclage in the prevention of preterm birth: a systematic review and meta-analysis

OBJECTIVE

Vaginal progesterone and cervical cerclage are both effective interventions for reducing preterm birth. It is currently unclear whether combined therapy offers superior effectiveness than single therapy. This study aimed to determine the efficacy of combining cervical cerclage and vaginal progesterone in the prevention of preterm birth.

DATA SOURCES

We searched Medline (Ovid), EMBASE (Ovid), PsycINFO (Ovid), CINAHL (EBSCOhost), Cochrane Library (Wiley), and Scopus (from their inception to 2020).

STUDY ELIGIBILITY CRITERIA

The review accepted randomized and pseudorandomized control trials, nonrandomized experimental control trials, and cohort studies. High risk patients (shortened cervical length <25mm or previous preterm birth) who were assigned cervical cerclage, vaginal progesterone, or both for the prevention of preterm birth were included. Only singleton pregnancies were assessed.

METHODS

The primary outcome was birth <37 weeks. Secondary outcomes included birth <28 weeks, <32 weeks and <34 weeks, gestational age at delivery, days between intervention and delivery, preterm premature rupture of membranes, cesarean delivery, neonatal mortality, neonatal intensive care unit admission, intubation, and birthweight. Following title and full-text screening, 11 studies were included in the final analysis. Risk of bias was assessed using the Cochrane Collaboration tool for assessing the risk of bias (ROBINS-I and RoB-2). Quality of evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluations) tool.

RESULTS

Combined therapy was associated with lower risk of preterm birth at <37 weeks than cerclage alone (risk ratio, 0.51; 95% confidence interval, 0.37-0.79) or progesterone alone (risk ratio, 0.75; 95% confidence interval, 0.58-0.96). Compared with cerclage only, combined therapy was associated with preterm birth at <34 weeks, <32 weeks, or <28 weeks, decreased neonatal mortality, increased birthweight, increased gestational age, and a longer interval between intervention and delivery. Compared with progesterone alone, combined therapy was associated with preterm birth at <32 weeks, <28 weeks, decreased neonatal mortality, increased birthweight, and increased gestational age. There were no differences in any other secondary outcomes.

CONCLUSION

Combined treatment of cervical cerclage and vaginal progesterone could potentially result in a greater reduction in preterm birth than in single therapy. Further, well-conducted and adequately powered randomized controlled trials are needed to assess these promising findings.

The clinical utility of ongoing sonographic cervix length surveillance in pregnancies prescribed vaginal progesterone therapy

BACKGROUND

Vaginal progesterone therapy significantly reduces preterm birth (PTB) rates in those high-risk pregnancies with a sonographic short cervix (≤25 mm) and/or a history of spontaneous PTB. Cervical length (CL) is routinely measured at the midtrimester morphology scan; however, CL surveillance thereafter is not currently recommended. Progesterone's precise mechanism of action remains unknown, though if it indeed influences CL, shortening after treatment initiation could indicate therapeutic failure and risk of PTB.

AIMS

The aim was to explore the utility of serial transvaginal ultrasound (TVU) measurement of CL at 16, 19 and 22 weeks for predicting PTB in high-risk pregnancies prescribed progesterone therapy.

METHODS

A retrospective cohort study was conducted involving women who attended the King Edward Memorial Hospital PTB Prevention Clinic from 2015 to 2019 and were prescribed progesterone therapy. CL was measured at 16, 19 and 22 weeks by TVU. CL change across three time points was assessed using linear mixed models; then relationships between CL change between 16-19 and 19-22 weeks and PTB were analysed using logistic regression models.

RESULTS

Term birth was most likely when CL did not decrease across both time periods. The addition of 16-19 week decrease in CL to a model, including CL at 19 weeks alone, for predicting PTB increased sensitivity from 43.2 to 56.3%, specificity from 73.2 to 77.4%, and overall accuracy from 61.7 to 70.2%.

CONCLUSION

For high-risk women prescribed vaginal progesterone therapy, serial measurement of the cervix at 16 and 19 weeks improves clinical ability to predict PTB from current recommendations of 19-week measurement alone.

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.

Progestogens for the prevention of preterm birth and risk of developing gestational diabetes mellitus: a meta-analysis

BACKGROUND

Several articles have implied that progestogen supplementation during pregnancy to reduce the risk of preterm birth may increase the risk for developing gestational diabetes mellitus.

OBJECTIVE

The purpose of the present meta-analysis was to accumulate existing evidence concerning this correlation.

DATA SOURCES

We searched Medline (1966-2019), Scopus (2004-2019), Clinicaltrials.gov (2008-2019), EMBASE (1980-2019), Cochrane Central Register of Controlled Trials CENTRAL (1999-2019), and Google Scholar (2004-2019) databases.

STUDY ELIGIBILITY CRITERIA

Randomized trials and observational studies were considered eligible for inclusion in the present meta-analysis. To minimize the possibility of article losses, we avoided language, country, and date restrictions.

STUDY APPRAISAL AND SYNTHESIS METHODS

The methodological quality of included studies was evaluated with the Cochrane risk of bias and the Risk Of Bias In Non-Randomized Studies of Interventions (ROBINS-I) tool. Meta-analysis was performed with the RevMan 5.3 and secondary analysis with the Open Meta-Analyst software. Trial sequential analysis was conducted with the trial sequential analysis program.

RESULTS

Overall, 11 studies were included in the present meta-analysis that recruited 8085 women. The meta-analysis revealed that women who received 17-alpha hydroxyprogesterone caproate had increased the risk of developing gestational diabetes mellitus (risk ratio, 1.73, 95% confidence interval, 1.32-2.28), whereas women who received vaginal progesterone had a decreased risk, although the effect did not reach statistical significance because of the unstable estimate of confidence intervals (risk ratio, 0.82, 95% confidence interval, 0.50-1.12). Meta-regression analysis indicated that neither the methodological rationale for investigating the prevalence of gestational diabetes mellitus (incidence investigated as primary or secondary outcome) (coefficient of covariance, -0.36, 95% confidence interval, -0.85 to 0.13, P = .154) nor the type of investigated study (randomized controlled trial/observational) (coefficient of covariance -0.361, 95% confidence interval, -1.049 to 0.327, P = .304) significantly altered the results of the primary analysis. Trial sequential analysis suggested that the meta-analysis concerning the correlation of 17-alpha hydroxyprogesterone caproate was of adequate power to reach firm conclusions, whereas this was not confirmed in the case of vaginal progesterone.

CONCLUSION

The results of the present meta-analysis clearly indicate that women who receive supplemental 17-alpha hydroxyprogesterone caproate for the prevention of preterm birth have an increased risk of developing gestational diabetes mellitus. On the other hand, evidence concerning women treated with vaginal progesterone remains inconclusive.