Induction of labor in patients with an unfavorable cervix after a cesarean using an osmotic dilator versus vaginal prostaglandin

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..

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.

Longitudinal Ultrasound Evaluation of Dilapan-S During Cervical Ripening

OBJECTIVE

To assess the diameter change of hygroscopic rod dilation during 12 hours of cervical ripening.

METHODS

This was an observational, prospective study of term women undergoing labor induction with a bishop score ≤ 6. Women were allocated into two groups (soaked gauze or no gauze) stratified by parity. Using transvaginal ultrasound, maximal rod diameters were obtained in a longitudinal plane. Measurements were taken at four pre-specified time points (3, 6, 8, and 12 hours). All rods were removed at 12 hours from insertion. Patient satisfaction scores between the groups were assessed. To evaluate if measures were significantly different among the four time points, a generalized linear model was used. Independent t-tests were used to compare mean rod diameter values and pain measures between the two groups. Fisher Exact tests were used to evaluate categorical satisfaction measures.

RESULTS

Forty-four women were recruited with a total of 178 hygroscopic rods placed. Mean rod diameters (mm) were significantly different among the four time periods (3 hour: 7.9 mm [SD 0.9]; 6 hour: 9.4 mm [SD 0.9]; 8 hour: 10.0 mm [SD 0.9]; 12 hour: 10.9 mm [SD 0.8]; P-value <.001). After stratifying by the use of gauze, there was no difference in rod diameters at 3, 6, 8, and 12 hours respectively. There was no difference in patient satisfaction scores between the two groups.

CONCLUSION

The majority of hygroscopic rod dilation occurs within the first 8 hours of cervical ripening. Placement of saturated gauze does not accelerate rod dilation.

Cervical ripening as an outpatient procedure in the pandemic - minimizing the inpatient days and lowering the socioeconomic costs

OBJECTIVES

With an increasing incidence of labor induction the socioeconomic costs are increasing and the burden on hospital capacities is rising. In addition, the worldwide SARS-CoV-2 pandemic asks for improvements in patient care during pregnancy and delivery while decreasing the patient-staff contact. Here, we are retrospectively analyzing and comparing a mechanical ripening device that is utilized as an outpatient procedure to misoprostol and dinoprostone as inpatient induction methods in a low risk cohort.

METHODS

This is a retrospective comparative analysis of obstetric data on patients who presented for cervical ripening and labor induction. Ninety-six patients received a mechanical ripening agent as an outpatient procedure. As a control group, we used 99 patients with oral misoprostol (PGE1) and 42 patients with vaginal dinoprostone (PGE2) for cervical ripening in an inpatient setting. Data from 2016 until 2020 were analysed.

RESULTS

Baseline characteristics showed no significant differences. Delivery modes were similar in all groups. The time period from patient admission to onset of labor was significantly shorter in the outpatient group (p<0.001): 10.9 h/0.5 days (±13.6/0.6) for osmotic dilator vs. 17.9 h/0.7 days (±13.1/0.5) for oral misoprostol vs. 21.8 h/0.8 days (±15.9/0.7) for vaginal dinoprostone. With 20.4 h/0.8 days (±14.3/0.6) the osmotic dilator group displayed significantly the shortest inpatient stay from admission to delivery (p=0.027). The patient subgroup of misoprostol had 25.7 h/1.1 days (±14.9/0.6) of inpatient stay from admission to delivery and the patient group of dinoprostone 27.5 h/1.1 days (±16.0/0.7). There were fewer hospital days in the outpatient group: 84.9 h/3.5 days vs. 88.9 h/3.7 days vs. 93.6 h/3.9 days (outpatient osmotic dilator vs. inpatient misoprostol and dinoprostone, respectively).

CONCLUSIONS

New approaches are required to decrease individual contacts between patients and staff while maintaining a high quality patient care in obstetrics. This analysis reveals that outpatient mechanical cervical ripening can be as safe and effective as inpatient cervical ripening with PGE1/PGE2, while lowering patient-staff contact and total hospital stays and therefore decreasing the socioeconomic costs.

Mechanical Methods for the Induction of Labour After Previous Caesarean Section – An Updated, Evidence-based Review

There are currently no up-to-date evidence-based recommendations on the preferred method to induce labour after previous Caesarean section, especially for patients with unripe cervix, as randomised controlled studies are lacking. Intravenous oxytocin and misoprostol are contraindicated in these women because of the high risk of uterine rupture. In women with ripe cervix (Bishop Score > 6), intravenous administration of oxytocin is an effective procedure with comparable rates of uterine rupture to those with spontaneous onset of labour. Vaginal prostaglandin E ₂ (PGE ₂ ) and mechanical methods (balloon catheters, hygroscopic cervical dilators) are effective methods to induce labour in pregnant women with unripe cervix and previous Caesarean section. According to current guidelines, the administration of PGE ₂ is associated with a higher rate of uterine rupture compared to balloon catheters. Balloon catheters are therefore a suitable alternative to PGE ₂ to induce labour after previous Caesarean section, even though this is an off-label use. In addition to two meta-analyses published in 2016, 12 mostly retrospective cohort/observational studies with low to moderate levels of evidence have been published on mechanical methods of cervical ripening after previous Caesarean section. But because of the significant heterogeneity of the studies, substantial differences in study design, and insufficient numbers of pregnant women included in the studies, it is not possible to make any evidence-based recommendations based on these studies. According to a recent meta-analysis, the average rate using balloon catheters is approximately 53% and the average rate after spontaneous onset of labour is 72%. The uterine rupture rate was 0.2–0.9% for vaginal PGE ₂ and 0.56–0.94% for balloon catheters and is therefore comparable to the uterine rupture rate associated with spontaneous onset of labour. According to the product informations, hygroscopic cervical dilators (Dilapan-S) are currently the only method which is not contraindicated for cervical ripening/induction of labour in women with previous Caesarean section, although data are insufficient. Well-designed, randomised, controlled studies with sufficient case numbers comparing balloon catheters and hygroscopic cervical dilators with mechanical methods and vaginal prostaglandin E ₂ /oral misoprostol are therefore necessary to allow proper decision-making.

Cervical ripening after cesarean section: a prospective dual center study comparing a mechanical osmotic dilator vs. prostaglandin E2

OBJECTIVES

Worldwide, the overall cesarean section is rising. Trial of labor after cesarean (TOLAC) is an overall safe option with an immediate impact on neonatal and maternal short- and long-term health. Since the use of prostaglandins in cervical ripening is associated with an increased risk of uterine rupture, mechanical methods as balloon catheters or osmotic dilators have been suggested for cervical ripening prior to induction of labour. Here we are analyzing and comparing the VBAC rate, as well as maternal and fetal outcome in cervical ripening prior to TOLAC.

METHODS

This prospective dual center study analyses maternal and neonatal outcomes of TOLAC in women with an unfavorable cervix requiring cervical ripening agent. The prospective application of an osmotic dilator (Dilapan-S, n=104) was analysed in comparison to the retrospective application of off-label dinoprostone (n=102).

RESULTS

The overall fetal and neonatal outcome revealed no significant differences in both groups. Patients receiving cervical ripening with the osmotic dilator delivered vaginally/by ventouse in 52% of cases, compared to 53% when using dinoprostone (p=0.603). The interval between application to onset of labor was significantly higher in the osmotic dilator group (37.9 vs.20.7 h, p=<0.001). However, time from onset of labor to delivery was similar in both groups (7.93 vs. 7.44 h, p=0.758). There was one case of uterine rupture in the dinoprostone group.

CONCLUSIONS

Our data shows that the application of the osmotic dilator leads to similar outcomes in VBAC rate and time from onset of labor to delivery as well as safety in both groups compared to off-label use dinoprostone. Cervical ripening using the mechanical dilator is a viable and effective option, without the risk of uterine hyperstimulation.

Out-of-Hospital Cervical Ripening With a Synthetic Hygroscopic Cervical Dilator May Reduce Hospital Costs and Cesarean Sections in the United States-A Cost-Consequence Analysis

Objective: Out-of-hospital (outpatient) cervical ripening prior to induction of labor (IOL) is discussed for its potential to decrease the burden on hospital resources. We assessed the cost and clinical outcomes of adopting an outpatient strategy with a synthetic hygroscopic cervical dilator, which is indicated for use in preinduction cervical ripening.

Methods: We developed a cost-consequence model from the hospital perspective with a time period from IOL to post-delivery discharge. A hypothetical cohort of women to undergo IOL at term with an unfavorable cervix (all risk levels) were assessed. As the standard of care (referred to as IP-only) all women were ripened as inpatients using the vaginal PGE2 insert or the single-balloon catheter. In the comparison (OP-select), 50.9% of low-risk women (41.4% of the study population) received outpatient cervical ripening using a synthetic hygroscopic cervical dilator and the remaining women were ripened as inpatients as in the standard of care. Model inputs were sourced from a structured literature review of peer-reviewed articles in PubMed. Testing of 2,000 feasible scenarios (probabilistic multivariate sensitivity analysis) ascertained the robustness of results. Outcomes are reported as the average over all women assessed, comparing OP-select to IP-only.

Results: Implementing OP-select resulted in hospital savings of US$689 per delivery, with women spending 1.48 h less time in the labor and delivery unit and 0.91 h less in the postpartum recovery unit. The cesarean-section rate was decreased by 3.78 percentage points (23.28% decreased to 19.50%). In sensitivity testing, hospital costs and cesarean-section rate were reduced in 91% of all instances.

Conclusion: Our model analysis projects that outpatient cervical ripening has the potential to reduce hospital costs, hospital stay, and the cesarean section rate. It may potentially allow for better infection-prevention control during the ongoing COVID-19 pandemic and to free up resources such that more women might be offered elective IOL at 39 weeks.

Prediction of successful vaginal birth after cesarean in women with diabetic disorders and no prior vaginal delivery

OBJECTIVE

To study the factors associated with successful trial of labor after cesarean (TOLAC) among women with diabetes and no prior vaginal delivery and compare with TOLAC in nondiabetic women.

METHODS

A retrospective study including all women undergoing TOLAC who had no prior vaginal delivery between March 2011 and June 2020 at Sheba Medical Center. Women with diabetic disorders were compared with those without. Multivariate regression analysis was performed to identify factors independently associated with TOLAC success.

RESULTS

Of 2144 deliveries with TOLAC, 163 (7.6%) were to women with a diabetic disorder. TOLAC success rate was comparable between diabetic and nondiabetic women (124 [76.1%] vs 1513 [76.4%], respectively; P = 0.931). Uterine rupture rate was 1.1% (23 out of 2144). Among women with diabetes the uterine rupture rate was 0.6% (1 out of 163) and did not differ between the success or fail TOLAC groups. Multivariate logistic regression showed that epidural anesthesia and cervical effacement were the only independent factors associated with TOLAC success in women with diabetes (adjusted OR 3.32; 95% CI, 1.31-8.69, P = 0.011 and aOR 1.04; 95% CI, 1.01-1.07, P = 0.007, respectively).

CONCLUSION

TOLAC in women with diabetes with no prior vaginal delivery has a high success rate. Epidural analgesia is the only modifiable independent predictor of TOLAC success.

Comparing the efficacy of dilapan with extra-amniotic saline infusion and oral misoprostol for cervical ripening in term pregnancies

INTRODUCTION

Labor induction is an important issue in modern obstetrics. One of the important factors for the success of induction of labor is the Bishop score of cervix.

OBJECTIVE

The purpose of the present study was to evaluate and compare the efficacy of dilapan with extra-amniotic saline infusion and oral misoprostol for cervical ripening in term pregnancies.

METHODS

This clinical trial study was performed on 120 nulliparous pregnant women with the Bishop score of less than 5. Group one, group two and group three received dilapan, extra amniotic saline infusion (EASI) and misoprostol respectively. All three groups were compared for duration from beginning of the intervention up to cervical ripening and Bishop Score of ≥7, duration of active phase and the second stage of labor, number of deliveries in the first 24 h, duration from beginning of the intervention up to delivery, rout of delivery as well as neonatal weight, neonatal Apgar score; hyper- stimulation, and need for oxytocin and oxytocin doses administered after 12 h of intervention.

RESULTS

The number of deliveries in the first 24 h after intervention were not significantly different between the three groups. There was no significant difference between the three groups according to duration from beginning of the intervention up to cervical ripening and Bishop Score of ≥7, duration of active phase and the second stage of labor, duration from beginning of the intervention up to delivery, rout of delivery as well as neonatal weight, neonatal Apgar score; and hyperstimulation. The Bishop Score was higher in the misoprostol group 6 h after intervention [dilapan: 4.32 ± 1.38, EASI: 5.47 ± 1.28, and misoprostol: 6.72 ± 1.61 (p = .000)], Oxytocin requirement [dilapan: 38 (95%) women, EASI: 37 (92.50%) and misoprostol: 30 (75%) women, p = .013], and required dose [dilapan: 7543 ± 2465 miu/ml, EASI: 5758 ± 1615miu/ml and misoprostol: 4930 ± 2589miu/ml, p = .000] were lower in misoprostol group.

CONCLUSION

Dilapan is an effective and safe method for cervical ripening in full term gestations. In cases where misoprostol and EASI cannot be used or are not desirable, dilapan can be used as an alternative.Trial registration number and registry website: IRCT20091023002624N25.

A comparison between labor induction with only Dilapan-S and a combination of mifepristone and Dilapan-S in nulliparous women: a prospective pilot study

OBJECTIVE

The aim of our study was to determine whether the combination of mifepristone and the osmotic dilator Dilapan-S improves the labor induction outcomes as compared to Dilapan-S alone.

METHODS

This prospective comparative study included 127 eligible women, of whom 58 underwent cervical ripening with Dilapan-S (12-h exposure, the control group) and 69 with Dilapan-S, with a concurrent pretreatment of 200 mg oral mifepristone (the study group), 8 h before Dilapan-S insertion.

RESULTS

The vaginal delivery rate in the control group and the study group was 60.3 and 76.8% (p = .045), respectively; the induction to delivery interval was 22.74 ± 3.01 h and 19,890 ± 2.42 h (p < .001), respectively; and the number of births within 24 h was 43.1 and 73.9% (p < .001), respectively. There was no difference in the rate of failed labor induction (6.9 versus 8.7%, p = .939). The Bishop's score improved significantly after the combined treatment as compared to with Dilapan alone (3.10 ± 0.58 versus 4.03 ± 1.35, p < .001). Moreover, in the study group, labor started earlier and proceeded faster with a lower additional oxytocin usage for labor induction or augmentation. There were no differences in the operative delivery rate and the perinatal outcomes. There were no adverse side effects of both mifepristone and Dilapan-S.

CONCLUSION

Our study is the first one to show that in comparison to labor induction using only osmotic dilators Dilapan-S, the combination of mifepristone and Dilapan-S is more efficient in terms of improving cervical ripening and vaginal delivery rate and reducing labor duration and frequency of oxytocin augmentation. The results revealed that this combined method is safe and has no immediate adverse effects on newborns. More studies are needed to evaluate what clinical cases are the most appropriate for the application of this combined method, considering the parity, degree of cervical ripening, and indication for labor induction.