A randomized trial of synthetic osmotic cervical dilator for induction of labor vs dinoprostone vaginal insert

Cervical Osmotic Dilators versus Dinoprostone for Cervical Ripening during Labor Induction: A Systematic Review and Meta-analysis of 14 Controlled Trials

OBJECTIVE

 This study aimed to conduct a systematic review and meta-analysis of all randomized and nonrandomized controlled trials (RCTs and NCTs, respectively) that explored the maternal-neonatal outcomes of cervical osmotic dilators versus dinoprostone in promoting cervical ripening during labor induction.

STUDY DESIGN

 Six major databases were screened until August 27, 2022. The quality of included studies was evaluated. The data were summarized as mean difference or risk ratio (RR) with 95% confidence interval (CI) in a random-effects model.

RESULTS

 Overall, 14 studies with 15 arms were analyzed (n = 2,380 patients). Ten and four studies were RCTs and NCTs, respectively. The overall quality for RCTs varied (low risk n = 2, unclear risk n = 7, and high risk n = 1), whereas all NCTs had good quality (n = 4). For the primary endpoints, there was no significant difference between both groups regarding the rate of normal vaginal delivery (RR = 1.04, 95% CI: 0.95-1.14, p = 0.41) and rate of cesarean delivery (RR = 1.04, 95% CI: 0.93-1.17, p = 0.51). Additionally, there was no significant difference between both groups regarding the mean change in Bishop score and mean time from intervention to delivery. The rate of uterine hyperstimulation was significantly lower in the cervical osmotic dilator group. For the neonatal outcomes, during cervical ripening, the rate of fetal distress was significantly lower in the cervical osmotic dilator group. There was no significant difference between both groups regarding the mean Apgar scores, rate of meconium-stained amniotic fluid, rate of umbilical cord metabolic acidosis, rate of neonatal infection, and rate of neonatal intensive care unit admission.

CONCLUSION

 During labor induction, cervical ripening with cervical osmotic dilators and dinoprostone had comparable maternal-neonatal outcomes. Cervical osmotic dilators had low risk of uterine hyperstimulation compared with dinoprostone. Overall, cervical osmotic dilators might be more preferred over dinoprostone in view of their analogous cervical ripening effects, comparable maternal-neonatal outcomes, and lack of drug-related adverse events.

KEY POINTS

· This is the first analysis of cervical osmotic dilators versus PGE2 for cervical ripening during labor.. · There was no difference between both arms regarding the rates of normal vaginal/cesarean deliveries.. · There was no difference between both arms regarding the rates of neonatal adverse events.. · Cervical osmotic dilators had significant lower risk of uterine hyperstimulation compared with PGE2.. · Cervical osmotic dilators may be superior to PGE2 in view of their similar efficacy and better safety..

Randomized control trial comparing hygroscopic cervical dilators to cervical ripening balloon for outpatient cervical ripening

BACKGROUND

Outpatient term preinduction cervical ripening with mechanical agents has been associated with reduced length of stay, decreased cesarean delivery rates, low maternal and neonatal complications, and increased incidence of vaginal delivery within 24 hours.

OBJECTIVE

This study aimed to demonstrate equivalent efficacy between synthetic hygroscopic dilators and the single-balloon catheter for outpatient cervical ripening.

STUDY DESIGN

This randomized control equivalence trial compared synthetic hygroscopic dilators with the 30-mL silicone single-balloon catheter in primiparous and multiparous patients undergoing labor induction. The primary outcome was time from admission to delivery, with a prespecified 3-hour margin of equivalence. The secondary objectives were patient outcomes and perspectives.

RESULTS

Between March 1, 2019, and May 31, 2021, 1605 patients met the screening criteria, and 174 patients completed the study. The mean admission-to-delivery time was equivalent at 18.01 hours for the dilator group vs 17.55 hours for the balloon group (P=.04). The cesarean delivery rate of primiparous patients was similar at 28.1% with dilators vs 29.7% with the balloon. The groups had similar median cervical dilation and pain scores on insertion and admission. Overall patient satisfaction was high, 92.8% with dilators vs 96.2% with the balloon. The balloon group had significantly higher rates of early admission and device expulsion.

CONCLUSION

Although the enrollment goal was not met, our study suggests that synthetic hygroscopic dilators and the single-balloon catheter for outpatient cervical ripening are both efficacious with similar time from admission to delivery, pain scores, and patient satisfaction with the procedure.

Optimal cervical-ripening method for labor induction in Japan after the era of controlled-release dinoprostone vaginal insert

OBJECTIVE

To investigate the predictive value of obstetric findings when using dinoprostone (prostaglandin E2 [PGE2]) vaginal inserts for cervical ripening, and to assess the optimal cervical-ripening method between PGE2 vaginal insert and/or cervical dilators.

METHODS

This prospective observational study enrolled pregnant women who underwent cervical ripening for labor induction in 37-41 week' gestation in 2020. In evaluation 1, optimal obstetric findings predictive of rapid cervical ripening using PGE2 were assessed. In evaluation 2, the duration from PGE2 administration to labor onset and perinatal outcomes were compared between cases in which only PGE2 was used and cases that were treated with PGE2 after mechanical cervical dilators (Dilapan®) for extremely immature cervical ripening (uterine cervical os <2 cm).

RESULTS

In evaluation 1, uterine dilatation before the use of a PGE2 vaginal insert was mostly correlated with the time from PGE2 administration to labor onset (r = -0.428, p < 0.001). When the uterine cervical os dilatation was ≥2 cm, a shorter time-to-labor onset was found. In addition, os dilatation, effacement, and station at the time of PGE2 vaginal insert removal also significantly progressed. In evaluation 2, the median duration from PGE2 administration to labor onset was 1740 min in cases where only PGE2 was used, and 610 min in those where PGE2 was used after mechanical cervical dilators (p = 0.011).

CONCLUSION

PGE2 vaginal inserts are relatively effective when the uterine cervical os is ≥2 cm in diameter. However, in cases of extremely immature cervical-ripening, it was feasible to use PGE2 vaginal inserts before mechanical cervical dilatation.

Synthetic Osmotic Dilators for Pre-Induction Cervical Ripening - an Evidence-Based Review

Mechanical methods have gained growing interest for pre-induction cervical ripening in women with an unripe cervix, since they have a better safety profile compared to prostaglandins. Balloon catheters have been the gold standard method for decades, while there was a lack of data on synthetic osmotic cervical dilators. Not until 2015, when Dilapan-S was approved by the Food and Drug Administration (FDA) for induction of labor, numerous studies have been published on the use of Dilapan-S in this field. The rate of vaginal deliveries associated with the use of Dilapan-S ranges from 61.6 to 81.7%, and no serious complications needing further interventions have been reported to this date. Dilapan-S was shown to be as effective as the Foley balloon catheter as well as the 10 mg PGE 2 vaginal insert and orally applied misoprostol (25 µg every 2 hours) in achieving vaginal delivery, but patient's satisfaction during the cervical ripening process was significantly higher compared to the other methods and the rate of uterine hyperstimulation was significantly lower compared to prostaglandins (PGs). Minor complications (e.g. vaginal bleeding) associated with the use of Dilapan-S were < 2%, and maternal infectious morbidity was not higher compared to Foley balloon and vaginal PGE 2 or misoprostol. Due to these beneficial properties Dilapan-S might be an ideal option for outpatient cervical ripening, as shown in a recent randomized clinical trial comparing inpatient to outpatient cervical ripening. Furthermore, according to the manufacturers' product information, Dilapan-S is the only cervical ripening method that is not contraindicated for induction of labor in women with a previous cesarean section. Upcoming guidelines should consider synthetic osmotic cervical dilators as an effective and safe method for cervical ripening/induction of labor acknowledging that more evidence-based data are mandatory, particularly in patients with a previous cesarean section.

Using dinoprostone slow release vaginal insert for cervical ripening in term-pregnancy with oligohydramnios

AIMS

The study purposed to evaluate the success rate of cervical ripening using dinoprostone controlled-release vaginal insert and reveal some factors relating to successful cervical ripening.

METHODS

This cross-sectional study was conducted at Tu Du Hospital in Vietnam from December 2021 to August 2022. The study enrolled 200 pregnant women with gestational age ≥37 weeks diagnosed with oligohydramnios. These candidates underwent dinoprostone cervical ripening (DCR) according to the local protocol. The Bishop score ≥7 after 24 h was determined for the successful cervical ripening (SCR).

RESULTS

In total, the success rate of DCR achieved at 57.5% and the cesarean delivery rate was 46.5%. None of the severe side-effects and complications was present. Using multivariable logistic regression, the study found that the body mass index ≥25 kg/m² and oxytocin infusion drip related to SCR with adjusted odds ratio (aOR): 3.67 (95% confidence intervals [CI]: 1.78-7.57) and aOR: 4.68 (95% CI: 1.84-11.93), p < 0.001. Using the Kaplan-Meier curve, the present study revealed a significant difference between Bishop <3 and ≥3 following the duration time of cervical ripening, with hazard ratio: 1.38 (95% CI: 1.19-1.59), p < 0.001. The time duration of cervical ripening was not significantly different following amniotic fluid index from 3 to 5 cm.

CONCLUSIONS

Cervical ripening using a dinoprostone vaginal insert is a potentially acceptable method in term pregnancy accompanying with oligohydramnios. The probability of SCR can be predicted on a careful assessment of relative factors by obstetricians. Further studies are required to strengthen these findings.

Experience of induction of labour: a cross-sectional postnatal survey of women at UK maternity units

OBJECTIVES

This study explored women's views and experiences of key elements of the induction of labour (IOL) process, including at home or in hospital cervical ripening (CR).

DESIGN

A questionnaire-based postnatal survey undertaken as part of the CHOICE Study process evaluation. The questionnaire was administered online and included fixed response and free-text options.

SETTING

National Health Service maternity units in the UK.

PARTICIPANTS

309 women who had an IOL.

OUTCOME MEASURES

The primary outcome measure was experience of IOL. Few women returned home during CR, meaning that statistical comparison between those who experienced home-based and hospital-based CR was not possible. Findings are reported as descriptive statistics with content analysis of women's comments providing context.

RESULTS

Information to support choice and understand what to expect about IOL is often inadequate or unavailable. Having IOL can create anxiety and remove options for birth that women had hoped would enhance their experience. Although it can provide a more comfortable environment, home CR is not always an acceptable solution. Women described maternity care negatively impacted by staffing shortages; delays to care sometimes led to unsafe situations. Women who had a positive experience of IOL described supportive interaction with staff as a significant contribution to that.

CONCLUSIONS

Women do not experience IOL as a benign and consequence free intervention. There is urgent need for research to better target IOL and optimise safety and experience for women and their babies. Relatively few women were offered CR at home and further research is needed on this experience.

Clinicians' perspectives and experiences of providing cervical ripening at home or in-hospital in the United Kingdom

Induction of labour, or starting labour artificially, is offered when the risks of continuing pregnancy are believed to outweigh the risks of the baby being born. In the United Kingdom, cervical ripening is recommended as the first stage of induction. Increasingly, maternity services are offering this outpatient or 'at home', despite limited evidence on its acceptability and how different approaches to cervical ripening work in practice. There is also a paucity of literature on clinicians' experiences of providing induction care in general, despite their central role in developing local guidelines and delivering this care. This paper explores induction, specifically cervical ripening and the option to return home during that process, from the perspective of midwives, obstetricians and other maternity staff. As part of a process evaluation involving five case studies undertaken in British maternity services, interviews and focus groups were conducted with clinicians who provide induction of labour care. The thematic findings were generated through in-depth analysis and are grouped to reflect key points within the process of cervical ripening care: 'Implementing home cervical ripening', 'Putting local policy into practice', 'Giving information about induction' and 'Providing cervical ripening'. A range of practices and views regarding induction were recorded, showing how the integration of home cervical ripening is not always straightforward. Findings demonstrate that providing induction of labour care is complex and represents a significant workload. Home cervical ripening was seen as a solution to managing this workload; however, findings highlighted ways in which this expectation might not be borne out in practice. More comprehensive research is needed on workload impacts and possible lateral effects within other areas of maternity services.

Outpatient Compared With Inpatient Preinduction Cervical Ripening Using a Synthetic Osmotic Dilator: A Randomized Clinical Trial

OBJECTIVE

To assess whether outpatient cervical ripening with a synthetic osmotic dilator shortens the length of hospital stay in term pregnancies undergoing labor induction.

METHODS

Pregnant participants scheduled for labor induction at term with unfavorable cervix (less than 3-cm dilated and less than 60% effaced) and not requiring inpatient maternal or fetal monitoring were consented, and synthetic osmotic dilator rods were inserted on the day of scheduled induction. After reassuring fetal heart tracing, patients randomized to the outpatient group were asked to return 12 hours after insertion or sooner if needed. Those randomized to the inpatient group remained in the hospital. After the first round of ripening, additional ripening, oxytocin, and labor management were left up to the clinical health care professionals. The primary outcome was the proportion of participants with hospital stays longer than 48 hours. We estimated that a sample size of 338 would provide 85% power to detect a 30% difference between groups.

RESULTS

From November 2018 to November 2021, 339 participants were randomized (171 inpatient, 167 outpatient, one withdrawal). Four patients in the outpatient group were admitted before12 hours for suspected labor and rupture of membranes, and 19 in the inpatient group had the device removed before 12 hours. The proportion of participants with hospital stays longer than 48 hours was lower in the outpatient group compared with the inpatient group (89 [53%] vs 152 [89%], relative risk [RR] 0.60, 95% CI 0.52-0.70). Patients in the outpatient group had a shorter total length of stay and time from admission to active labor. They were more likely to have a vaginal delivery within 24 hours of admission and were less likely to receive analgesics during ripening. Route of delivery and other maternal and neonatal outcomes were not significantly different between groups.

CONCLUSION

Outpatient cervical ripening with a cervical osmotic dilator decreased hospital stay compared with inpatient ripening, without significant adverse outcomes.

FUNDING SOURCE

Medicem Technology s.r.o., Czech Republic.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT03665688.

Synthetic osmotic dilators (Dilapan-S) or dinoprostone vaginal inserts (Propess) for inpatient induction of labour: A UK cost-consequence model

OBJECTIVE

To estimate the costs of synthetic osmotic dilators (Dilapan-S) compared to dinoprostone vaginal inserts (Propess) for inpatient induction of labour (IOL).

STUDY DESIGN

A population-level, Markov model-based cost-consequence analysis was developed to compare the impact of using Dilapan-S versus Propess. The time horizon was modelled from admission to birth. The target population was women requiring inpatient IOL from 37 weeks with an unfavourable cervix in the UK. Mean population characteristics reflected those of the SOLVE (NCT03001661) trial. No patient data were included in this analysis. The care pathways and staff workload were modelled using data from the SOLVE trial and clinical experience. Cost and clinical inputs were sourced from the SOLVE trial and peer-reviewed literature. Costs were inflated to 2020 British pounds (GBP, £). Outcomes were reported as an average per woman for total costs and required staff time (minutes) from admission for IOL until birth. The model robustness was assessed using a probabilistic, multivariate sensitivity analysis of 2,000 simulations with results presented as the median (interquartile range, IQR).

RESULTS

Dilapan-S was cost neutral compared to Propess. Midwife and obstetrician times were decreased by 146 min (-11%) and 11 min (-54%), respectively. Sensitivity analysis showed that in 78% of simulations, use of Dilapan-S reduced midwife time with a median of -160 min (IQR -277 to -24 min). Costs were reduced in 54% of simulations (median -£33, IQR -£319 to £282).

CONCLUSIONS

The model indicates that adoption of Dilapan-S is likely to be cost-neutral and reduce staff workload in comparison to Propess. Results require support from real-world data and further exploration of Dilapan-S is to be encouraged.

Moving preinduction cervical ripening to a lower acuity inpatient setting using the synthetic hygroscopic cervical dilator: a cost-consequence analysis for the United States

BACKGROUND

Leveraging the safety profile of the synthetic hygroscopic cervical dilator (SHCD), one potential way to reduce the burden-of-care provision in the labor-and-delivery unit without compromising safety is to introduce a low-acuity care room (ripening room) for patients undergoing cervical ripening as a part of labor induction at term.

METHODS

Implementing a ripening room using SHCDs was compared to scenarios using prostaglandins including a dinoprostone insert (PGE2 insert) or gel (PGE2 gel) and misoprostol given orally (oral PGE1) or vaginally (vaginal PGE1). A theoretical, cost-consequence model was developed to assess costs, staff time, and selected clinical outcomes related to cervical ripening. The model assessed a hypothetical cohort where patients remained in hospital from admission for induction of labor (IOL) to delivery, taking the US labor-and-delivery unit perspective. Model inputs were taken from structured searches of PubMed and ClinicalTrials.gov, published US guidance, and clinical practice. Results are presented as mean (95% credible interval [CrI]).

RESULTS

The ripening room using SHCDs cost US$3,210 and required 10.22 hours (h) of nurse time on average per patient. The cost difference to prostaglandins ranged from -$894 (-$2,269 to $398) for PGE2 gel to +$460 (-$1,467 to $1,539) for vaginal PGE1. Mean nurse time was shorter than all prostaglandins, with time savings ranging from -7.05 (-24.55 to 5.73) h for PGE2 insert to -0.97 (-14.69 to 9.59) h for vaginal PGE1. When outcomes of the probabilistic sensitivity analysis were ranked from 1 (best) to 5 (worst), the ripening room using SHCDs ranked 1.94 for costs and 1.97 for nurse time. In a nulliparous population, results improved for the ripening room using SHCDs relative to all prostaglandins.

CONCLUSION

In this theoretical study, implementing a ripening room using SHCDs resulted in the lowest time burden and the second lowest costs. The cheapest option for preinduction cervical ripening was vaginal misoprostol.