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

Preinduction cervical ripening in an outpatient setting: a prospective pilot study of a synthetic osmotic dilator compared with a double-balloon catheter

OBJECTIVES

To compare the effectiveness, safety and patient satisfaction of a double balloon catheter (DB) with a synthetic osmotic cervical dilator (OD) for pre-induction cervical ripening in an outpatient setting.

METHODS

This is a prospective, dual-center pilot study including 94 patients with an unripe cervix (Bishop Score <6) near term; 50 patients received the DB and 44 patients the OD. The primary outcomes were the difference in Bishop Score (BS) and cervical shortening. Pain perception at insertion and during the cervical ripening period was evaluated by a visual analogue scale and patient satisfaction by a predefined questionnaire.

RESULTS

The use of DB was associated with a significantly higher increase in BS (median 3) compared to OD (median 2; p=0.002) and resulted in significantly greater cervical shortening (median -14 mm vs. -9 mm; p=0.003). There were no serious adverse events at placement of devices or during the cervical ripening. There were no significant differences in perinatal outcomes. Pain perception during cervical ripening was significantly higher (p<0.001), and patient satisfaction regarding sleep, relaxing time and performing desired daily activities were significantly lower in patients with DB compared to patients with OD (p<0.001).

CONCLUSIONS

DB was superior to OD regarding cervical ripening based on BS and on sonographic measurement of the cervical length. Patients with OD experienced less pain during cervical ripening and were more satisfied with the method compared to patients with DB.

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.

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.