Preinduction cervical ripening: basis and methods of current practice

Efficacy and safety of double balloon catheter and dinoprostone for labor induction in multipara at term

PURPOSE

The aim of this study was to comparatively assess the efficacy and safety of double balloon catheter (DBC) and dinoprostone as labor-inducing agents just for multipara at term.

METHODS

A retrospective cohort study was conducted among multipara at term with a Bishop score < 6 who needed planned labor induction from January 1, 2020, to December 30, 2020 in Maternal and Child Health Hospital of Hubei province, Tongji Medical College, Huazhong University of Science and Technology. They were divided into DBC group and dinoprostone group, respectively. Baseline maternal data, maternal and neonatal outcomes were recorded for statistical analysis. Total vaginal delivery rate, rate of vaginal delivery within 24 h, rate of uterine hyperstimulation combined with abnormal fetal heart rate(FHR) were regarded as the primary outcome variables. The difference between groups was considered statistically significant when p value < 0.05.

RESULTS

A total of 202 multiparas was included for analysis (95 women in DBC group vs 107 women in dinoprostone group). There were no significant differences in total vaginal delivery rate and rate of vaginal delivery within 24 h between groups. Uterine hyperstimulation combined with abnormal FHR occurred exclusively in dinoprostone group.

CONCLUSION

DBC and dinoprostone seem to be equally effective, while, DBC seems to be safer than dinoprostone.

Fetal heart rate patterns and the incidence of adverse events after oral misoprostol administration for cervical ripening among low-risk pregnancies

OBJECTIVE

Though misoprostol is commonly used for inpatient cervical ripening, its use in outpatient settings has been limited by safety concerns. This study was conducted to assess the association between early fetal heart tracing (FHT) and maternal tocodynamometry patterns and the incidence of adverse fetal and pregnancy outcomes after the administration of oral misoprostol for cervical ripening.

METHODS

We conducted a retrospective cohort study of 9908 low-risk patients at ≥37 weeks gestation who received oral misoprostol for cervical ripening prior to rupture of membranes between 01/01/2012 and 12/31/2017 at Kaiser Permanente Northern California hospitals as inpatients. We excluded patients who received a different agent for cervical ripening or had any need for additional inpatient monitoring, including hypertensive disorders of pregnancy, diabetes, or intrauterine growth restriction. Abnormal FHT, abnormal uterine activity, and adverse pregnancy or fetal-related events documented in the electronic health record in the four hours after administration of the first and second doses of misoprostol were assessed using descriptive statistics.

RESULTS

We found that 0.9% of patients experienced tachysystole after the first dose of misoprostol (0.6% without decelerations; 0.3% with decelerations). The incidence of variable decelerations only and other FHT abnormalities (i.e. bradycardia, late or prolonged decelerations, or absent or minimal variability) in the first hour after misoprostol administration were 7.1% and 6.7% respectively, and diminished over time. The need for tocolytic use was 0.2% in the first hour and declined over time to 0.03% in the fourth hour after the first dose. Urgent cesarean delivery occurred in 0.1% of patients after receiving the first dose of misoprostol. Patients who did not experience variable, prolonged, or late decelerations in the first hour after the initial misoprostol dose were less likely to have such FHT abnormalities in the subsequent three hours compared to patients who had other FHT abnormalities (11.8% among patients with no FHT abnormalities vs. 43.7% among patients with other FHT abnormalities; p <.001). The overall trends in outcomes over time were similar after the second dose of misoprostol.

CONCLUSION

The risk of short-term adverse outcomes associated with misoprostol is low among relatively low-risk patients. FHT abnormalities occurred in up to 32% of patients in the first four hours of monitoring post-misoprostol. Patients with no FHT abnormalities in the first hour after receiving misoprostol had a low risk of developing adverse outcomes and FHT abnormalities on continued monitoring, while patients with any type of deceleration in the first hour were at higher risk of adverse outcomes and FHT abnormalities. Our data may inform the development of protocols for cervical ripening that allow reduced monitoring for a subset of low-risk patients, however, more research is needed to validate findings and develop clinical protocols.

Different expressions of aquaporin water channels and macrophages infiltration in human cervix remodeling during pregnancy

Despite aquaporin water channels (AQPs) play a critical role in maintaining water homeostasis in female reproductive tract and prompt a gradual increase in water content in cervical edema as pregnancy progressed, their relationship with macrophage infiltration and collagen content in human cervical remodeling need to be further investigated. This is the first study to examine the expression and localization of AQP3, AQP4, AQP5, AQP8 and macrophages simultaneously in human cervical ripening. The immunoreactivity of these AQPs was 2.6 to 6-fold higher on gestational weeks 26 (GD26W) than that on GD6W and GD15W, but AQP4 expression on GD39W dropped a similar extent on GD15W, other AQPs continued to rise on GD39W. The AQP3, AQP4 and AQP5 intensity seemed more abundant in cervical stroma than in the perivascular area on GD26W; the distribution of AQP3, AQP5 and AQP8 in cervical stroma was equivalent to that in the perivascular area on GD39W. Macrophage numbers were 1.7-fold higher in subepithelium region and 3.0-fold higher in center area on GD26W than that on GD15W; such numbers remained elevated on GD39W. The electron micrographs showed that cervical extensibility increased significantly on GD26W and GD39W accompanied with increased macrophage infiltration, cervical water content and much more space among collagen fibers. These findings suggest that the upregulation of AQPs expression in human cervix is closely related to enhanced macrophage infiltration during pregnancy; there may be a positive feedback mechanism between them to lead the increase of water content and the degradation of collagen.

A randomized controlled trial of Dilapan-S vs Foley balloon for preinduction cervical ripening (DILAFOL trial)

OBJECTIVE

The objective of the study was to test the hypothesis that Dilapan-S is not inferior to the Foley balloon for preinduction cervical ripening at term.

STUDY DESIGN

Pregnant women ≥37 weeks scheduled for induction with unfavorable cervix (≤3 cm dilated and ≤60% effaced) were randomly assigned to 12 hours of either Foley balloon inflated with 60 mL saline or Dilapan-S for cervical ripening. If the cervix remained unfavorable, then 1 more round of the assigned dilator was used. Management following ripening was left up to the clinical providers. The primary outcome was vaginal delivery. A satisfaction survey was also obtained after the preinduction period. Sample size was based on a noninferiority margin of 10%, 90% power, and an estimated frequency of vaginal delivery of 71% in Foley balloon and 76% in Dilapan-S.

RESULTS

From November 2016 through February 2018, 419 women were randomized (209 to Foley balloon; 210 to Dilapan-S). In the intent-to-treat analysis, vaginal delivery was more common in Dilapan-S vs Foley balloon (81.3% vs 76.1%), with an absolute difference with respect to the Foley balloon of 5.2% (95% confidence interval, -2.7% to 13.0%) indicating noninferiority for the prespecified margin. The difference was not large enough to show superiority. Noninferiority was confirmed in the per-protocol population (n = 204 in the Foley balloon, n = 188 in Dilapan-S), supporting the robustness of the results. Secondary outcomes were not different between groups, except for a longer time the device remained in place in Dilapan-S compared with the Foley balloon. Maternal and neonatal adverse events were not significantly different between groups. A priori interaction analyses showed no difference in the effect on vaginal delivery by cervical dilation at randomization, parity, or body mass index >30 kg/m². Patients with Dilapan-S were more satisfied than patients with the Foley balloon as far as sleep (P = .01), relaxing time (P = .001), and performance of desired daily activities (P = .001).

CONCLUSION

Dilapan-S is not inferior to the Foley balloon for preinduction cervical ripening at term. Advantages of Dilapan-S over Foley include Food and Drug Administration approval, safe profile, no protrusion from the introitus, no need to keep under tension, and better patient satisfaction.

Intracervical Foley catheter balloon versus dinoprostone insert for induction cervical ripening: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Successful labor induction depends on the cervical status at the time of induction. Currently, both a Foley catheter and a dinoprostone insert are used for effective cervical ripening. This study compared the efficacy and safety of the intracervical Foley catheter and dinoprostone insert for cervical ripening to achieve successful labor induction.

METHODS

PubMed, Embase, and the Cochrane Library were searched from January 2000 to February 2017 for relevant articles. Only published randomized, controlled trials comparing the dinoprostone insert with the Foley catheter were included.

RESULTS

Eight trials including 1191 women who received the intracervical Foley catheter balloon and 1199 who received the dinoprostone insert were used for this study. There was no significant difference between the 2 groups regarding the induction-to-delivery (I-D) interval in a random effect model (mean difference, 0.71 hours; 95% confidence interval [CI], -2.50 to 3.91; P = .67). The highly significant heterogeneity (I = 97%) could be explained by the subgroup analysis of the type of Foley catheter and balloon volume. There was no significant difference between the 2 methods regarding the cesarean delivery rate (relative risk, 0.91; 95% CI, 0.78-1.07; P = .24), Apgar score, or side effects, including maternal infection rate, postpartum hemorrhage, and hyperstimulation. No obvious publication bias was found.

CONCLUSIONS

According to the cesarean delivery rate, the intracervical Foley catheter balloon was as efficient as the dinoprostone insert. A moderate balloon volume (30 mL) and higher dose of dinoprostone (≥6 mg) were related to shorter I-D intervals. Additionally, there was no significant difference between the two methods regarding maternal or neonatal safety.

Other mechanical methods for pre-induction cervical ripening

Pre-induction cervical ripening is an important part of the labor induction process in women with an unfavorable cervix. This can be achieved either by pharmacologic or mechanical methods of cervical ripening. While the Foley catheter is the most commonly used mechanical method for labor induction, other mechanical methods are also available. This article reviews the safety profiles of osmotic dilators, extra-amniotic saline infusion, double-balloon catheters, and also compares their efficacy to that of other mechanical and pharmacologic cervical ripening methods. While mechanical methods have been shown to be safe and effective for cervical ripening, none of these alternatives has been shown to be superior to the Foley catheter.

Effect of Acupressure on Cervical Ripening

BACKGROUND

Cervical ripening is one of the main stages of initiation labor. Acupressure in Chinese medicine is considered as an invasive technique, which through reliving oxytocin ripens the cervix. Acupoint Sanyinjiao (SP6) was selected in this study because it is the acupoint selected in gynecology and it is easy for women to locate and apply pressure without medical assistance.

OBJECTIVES

The aim of this study was to determine the effect of acupressure on cervical ripening.

PATIENTS AND METHODS

In this randomized clinical trial, 150 primigravida with term pregnancy who had referred to Deziani hospital in Gorgan were chosen and divided to three groups: in the first group acupressure was done by the researcher while in the second groups this was performed by the mother her self, and the third group served as a control and only received routine care. For both intervention groups the pressure was applied on Sp6 for about 20 minutes during one to five days. Elements were checked from cervical ripening at 48 and 96 hours after intervention and at the time of hospitalization. The tools for gathering information included demographic characteristics and midwifery history questionnaire, daily records and follow up forms. Content validity was used for validity of tools. Reliability of the observation check-list and physical examination was confirmed by inter-rater scores (inter observer), and daily records by test-re-test. Data was analyzed by analysis of variance (ANOVA), Kruskal-Wallis and Chi-squared tests (P ≤ 0.05).

RESULTS

There was a significant difference between mothers' educations in the three groups. Most of the mothers (59.5%) in the researcher-performed acupressure group had secondary education. Cervical ripening was significantly different between the three groups after 48 hours (P ≤ 0.05), yet there was no significant difference after 96 hours and at the time of admission. Mean Bishop score was enhanced after 48 hours in the researcher-performed acupressure group (P ≤ 0.021) and the self-performed acupressure group (P ≤ 0.007) in comparison to the control group.

CONCLUSIONS

The results showed that acupressure is a safe technique and leads to cervical ripening. Thus, regarding the desired results that were achieved when mothers applied acupressure themselves, it could be suggested that it is beneficial for mothers to be trained to apply this method at home.

Foley catheter or prostaglandin E2 inserts for induction of labour at term: an open-label randomized controlled trial (PROBAAT-P trial) and systematic review of literature

OBJECTIVE

To assess the safety and effectiveness of a transcervical Foley catheter compared to vaginal prostaglandin E2 inserts for term induction of labour.

STUDY DESIGN

We conducted an open-label randomized controlled trial in five hospitals in the Netherlands. Women with a singleton term pregnancy in cephalic presentation, intact membranes, unfavourable cervix, and no prior caesarean section were enrolled. Participants were randomly allocated by a web-based randomization system to induction of labour with a 30 ml Foley catheter or 10mg slow-release vaginal prostaglandin E2 inserts in a 1:1 ratio. Due to the nature of the intervention this study was not blinded. The primary outcome was the caesarean section rate. Secondary outcomes were maternal and neonatal morbidity and time from intervention to birth. Additionally, we carried out a systematic review and meta-analysis of similar studies.

RESULTS

We analyzed 226 women: 107 received a Foley catheter and 119 inserts. Caesarean section rates were comparable (20% versus 22%, RR 0.90, 95% CI 0.54-1.50). Secondary outcomes showed no differences. We observed no serious maternal or neonatal morbidity. Meta-analysis showed comparable caesarean section rates, but significantly fewer cases of hyperstimulation during the ripening phase when a Foley catheter was used.

CONCLUSIONS

We found, in this relatively small study, no differences in effectiveness and safety of induction of labour with a Foley catheter and 10mg slow release vaginal prostaglandin E2 inserts. Meta-analysis confirmed a comparable caesarean section rate, and showed fewer cases of hyperstimulation when a Foley catheter was used.

Cost-effectiveness of induction of labour at term with a Foley catheter compared to vaginal prostaglandin E₂ gel (PROBAAT trial)

OBJECTIVE

To assess the economic consequences of labour induction with Foley catheter compared to prostaglandin E2 gel.

DESIGN

Economic evaluation alongside a randomised controlled trial.

SETTING

Obstetric departments of one university and 11 teaching hospitals in the Netherlands.

POPULATION

Women scheduled for labour induction with a singleton pregnancy in cephalic presentation at term, intact membranes and an unfavourable cervix; and without previous caesarean section.

METHODS

Cost-effectiveness analysis from a hospital perspective.

MAIN OUTCOME MEASURES

We estimated direct medical costs associated with healthcare utilisation from randomisation to 6 weeks postpartum. For caesarean section rate, and maternal and neonatal morbidity we calculated the incremental cost-effectiveness ratios, which represent the costs to prevent one of these adverse outcomes.

RESULTS

Mean costs per woman in the Foley catheter group (n = 411) and in the prostaglandin E₂ gel group (n = 408), were €3297 versus €3075, respectively, with an average difference of €222 (95% confidence interval -€157 to €633). In the Foley catheter group we observed higher costs due to longer labour ward occupation and less cost related to induction material and neonatal admissions. Foley catheter induction showed a comparable caesarean section rate compared with prostaglandin induction, therefore the incremental cost-effectiveness ratio was not informative. Foley induction resulted in fewer neonatal admissions (incremental cost-effectiveness ratio €2708) and asphyxia/postpartum haemorrhage (incremental cost-effectiveness ratios €5257) compared with prostaglandin induction.

CONCLUSIONS

Foley catheter and prostaglandin E2 labour induction generate comparable costs.

Current pharmacotherapy options for labor induction

INTRODUCTION

Labor induction is now reported to occur in up to 30 - 40% of obstetrical patients. There are a number of pharmacological options available to facilitate labor induction, including oxytocin and analogues of prostaglandins E1 and E2, which have particular utility when labor induction necessitates cervical ripening, as when labor induction occurs in the context of an unfavorable cervix.

AREAS COVERED

This paper reviews acceptable pharmacological options for labor induction, especially when cervical ripening is required. These options include oxytocin and a number of prostaglandin formulations using dinoprostone and misoprostol. It also covers several analyses of published clinical trials (Phase-III) describing evidence of effectiveness.

EXPERT OPINION

Oxytocin is best used when labor needs to be induced in the context of a favorable cervix. When the cervix is not favorable, cervical ripening using prostaglandins should precede labor induction. Either dinoprostone or misoprostol are superior to oxytocin alone for cervical ripening. However, judicious, careful considerations need to be made at the outset of labor induction so as to balance maternal and fetal risks, and these should be guided by institutional policies that reflect the evidence-base.

Effect of hyoscine butylbromide first stage of labour in multiparus women

BACKGROUND

Prolonged labor is one of the most important risk factors for perinatal compromise and, if caused by obstructed labor, it carries the risk of uterine rupture, postpartum hemorrhage (PPH), puerperal sepsis, and maternal death.

OBJECTIVE

To determine whether or not hyoscine butylbromide shortens the stages of labor, without an increase in maternal or neonatal complications.

METHOD

In single-blinded randomized clinical trial study, 188 multiparas women in active phase of labor who were admitted to Shahid Sadoughi Hospital from October 2006 to April 2007 in Yazd - Iran, were evaluated. They were divided hyoscine group (n = 94) received 20mg (1ml) of hyoscine and control group (n = 94) received 1 ml of normal saline was given as placebo, intravenously. The effects of hyoscine in shortening labor time; and neonatal Apgar score was compared.

RESULTS

Duration of the first (mean± SD: 186.8 ± 125.6 minutes vs. 260.4 ± 120.9 minutes, p= 0.00 1) and second stage of labor (mean± SD: 20.0 ± 8.1minutes vs. 25.8 ± 9.4 minutes, p= 0.03) was shorter in hyoscine group. Frequency of cesarean section and mean of neonatal Apgar score at minutes of one and 5 were not different in both groups. No serious adverse events were seen in the two groups.

CONCLUSION

Injection of hyoscine in active phase of labor can be effective in shortening of labor without any adverse effect on mother and fetus.

Foley catheter versus vaginal prostaglandin E2 gel for induction of labour at term (PROBAAT trial): an open-label, randomised controlled trial

BACKGROUND

Induction of labour is a common obstetric procedure. Both mechanical (eg, Foley catheters) and pharmacological methods (eg, prostaglandins) are used for induction of labour in women with an unfavourable cervix. We aimed to compare the effectiveness and safety of induction of labour with a Foley catheter with induction with vaginal prostaglandin E2 gel.

METHODS

We did an open-label, randomised controlled trial in 12 hospitals in the Netherlands between Feb 10, 2009, and May 17, 2010. We enrolled women with a term singleton pregnancy in cephalic presentation, intact membranes, an unfavourable cervix, an indication for induction of labour, and no prior caesarean section. Participants were randomly allocated by an online randomisation system to induction of labour with a 30 mL Foley catheter or vaginal prostaglandin E2 gel (1:1 ratio). Because of the nature of the intervention this study was not blinded. The primary outcome was caesarean section rate. Secondary outcomes were maternal and neonatal morbidity and time from intervention to birth. All analyses were done on an intention-to-treat basis. We also did a meta-analysis that included our trial. The trial was registered with the Dutch trial registry, number NTR 1646.

FINDINGS

824 women were allocated to induction of labour with a Foley catheter (n=412) or vaginal prostaglandin E2 gel (n=412). Caesarean section rates were much the same between the two groups (23%vs 20%, risk ratio [RR] 1·13, 95% CI 0·87-1·47). A meta-analysis including our trial data confirmed that a Foley catheter did not reduce caesarean section rates. We recorded two serious maternal adverse events, both in the prostaglandin group: one uterine perforation and one uterine rupture.

INTERPRETATION

In women with an unfavourable cervix at term, induction of labour with a Foley catheter is similar to induction of labour with prostaglandin E2 gel, with fewer maternal and neonatal side-effects.

FUNDING

None.

Is transcervical Foley catheter actually slower than prostaglandins in ripening the cervix? A randomized study

OBJECTIVE

The purpose of this study was to determine whether the maximum time for cervical ripening (from 24-12 hours) would influence the efficacy of a transcervical Foley catheter and to compare efficacy to that of a prostaglandin E(2) vaginal insert.

STUDY DESIGN

Three hundred ninety-seven women were assigned randomly to (1) Foley catheter left in place for a maximum of 24 hours, (2) Foley catheter left in place for a maximum of 12 hours, or (3) prostaglandin E(2) controlled-release vaginal insert. Primary outcome was vaginal delivery within 24 hours.

RESULTS

There were no differences in vaginal delivery rates. The proportion of women who achieved vaginal delivery in 24 hours was lower in the 24-hour Foley catheter group than in the other 2 groups (24-hour Foley catheter, 21.0%; 12-hour Foley catheter, 59.8%; vaginal prostaglandin E(2), 48.5%; P < .0001).

CONCLUSION

Cutting the ripening time with a Foley catheter by one-half increases the proportion of women who deliver vaginally within 24 hours and yields efficacy similar to that of prostaglandin E(2) vaginal insert.

Intrauterine Resuscitation During Labor: Review of Current Methods and Supportive Evidence

When the fetal heart rate pattern is suggestive of fetal compromise during labor, various methods to promote fetal well-being are traditionally initiated. They include maternal repositioning, reduction of uterine activity, an intravenous fluid bolus, oxygen administration, correction of maternal hypotension, amnioinfusion, and alteration of second-stage labor pushing efforts. Although these intrauterine resuscitation techniques are commonly used, and in some cases considered standard care, supportive data could be more robust. Nevertheless, there is enough evidence to suggest they are beneficial to the fetus and there is minimal risk of harm when used with clinical common sense. Until more data are available, it seems reasonable to err on the side of fetal safety by using these techniques when appropriate, based on the specific fetal heart rate pattern.

Foley catheter balloon vs locally applied prostaglandins for cervical ripening and labor induction: a systematic review and metaanalysis

We performed a metaanalysis of publications comparing the efficacy and safety of cervical ripening and labor induction by Foley catheter balloon (FCB) vs locally applied prostaglandins (LAPG) in the third trimester of pregnancy. Twenty-seven randomized controlled trials (1966-2008; 3532 participants) were selected from MEDLINE, EMBASE, and CENTRAL searches. There was no significant difference between FCB and LAPG in cesarean delivery rates. LAPG had a significantly increased risk of excessive uterine activity (P = .001). FCB had a significantly higher risk of oxytocin induction/augmentation during labor (P = .0002). Cervical prostaglandin-E2 was less effective (P = .04), and vaginal prostaglandin-E1 bore a significantly higher risk of excessive uterine activity (P < .0001) and meconium staining (P = .04). We concluded that FCB and LAPG result in similar cesarean delivery rates, that FCB bears a higher risk of oxytocin use for labor induction and/or augmentation, and that LAPG carries a higher risk of contraction abnormalities.

Is misoprostol safe for labor induction in twin gestations?

OBJECTIVE

To compare the safety and efficacy of intravaginal misoprostol to oxytocin for the induction of labor in twin gestations.

METHODS

All twin gestations that underwent induction of labor with misoprostol or oxytocin during a 4-year period were identified from the Mount Sinai obstetrical database. Only twins > or = 34 weeks with a vertex presenting twin A were included. Labor and delivery characteristics, maternal complications and neonatal outcomes were compared between the two groups.

RESULTS

Of 134 patients with twins, 57 initially received misoprostol and 77 received oxytocin. These groups had similar demographics, but women who received misoprostol had less cervical dilation (0.8 vs. 2.2 cm, p < 0.0001) and were less likely to be multiparous (19% vs. 44%, p = 0.003). There was a shorter length of induction to delivery (7.8 hours vs. 15.1 hours, p = 0.001) and a trend toward a lower cesarean section rate (16.9% vs. 31.6%, p = 0.06) in the oxytocin-only group. There were no cases of uterine rupture or maternal mortality in this series. There were no significant differences in neonatal outcomes between the two groups, but the sample size was underpowered to detect significant differences between the groups.

CONCLUSIONS

Misoprostol and oxytocin both appear to be safe and efficacious for use in inductions of labor in twins in this limited retrospective investigation. The safety of these agents with regard to neonatal outcomes should be confirmed by larger studies.

The context & clinical evidence for common nursing practices during labor

The purpose of this article is to review the context and current evidence for common nursing care practices during labor and birth. Although many nursing interventions during labor and birth are based on physician orders, there are a number of care processes that are mainly within the realm of nursing practice. In many cases, particularly in community hospitals, routine physician orders for intrapartum care provide wide latitude for nurses in how they ultimately carry out those orders. An important consideration of common nursing practices during labor is the context or practice model in which those practices occur. Nursing practice is not the same in all clinical environments. Intrapartum nursing practice consists of an assortment of different roles depending on the circumstances, hospital setting, and context in which it takes place. A variety of intrapartum nursing practice models have evolved as a result and in response to the range of sizes, locations, and provider practice styles found in hospitals providing obstetric services. A summary of intrapartum nursing models is presented. The evidence is reviewed for the three most common clinical practices for which nurses have primary responsibility in most settings and that comprise the majority of their time in caring for women during labor: (1) maternal-fetal assessment, (2) management of oxytocin infusions, and (3) second-stage care. Evidence exists for these nursing interventions that can be used to promote maternal-fetal well-being, minimize risk, and enhance patient safety.

Clinical Use of Relaxin to Facilitate Birth: Reasons for Investigating the Premise

In the United States, both medical and nonmedical factors have driven the cesarean section rate to over 26% of all deliveries. In addition to questions of increased cost associated with operative delivery, some have questioned the ethics of performing cesarean section for nonmedical reasons. Reduction of both the duration and the pain associated with vaginal delivery would likely bring about a decline in the rate of both medical and nonmedical cesarean sections. This chapter summarizes recent findings that support the premise that through its growth-promoting and softening effects on the cervix, short-term subcutaneous administration of pharmacologic amounts of relaxin to women at term holds promise as a means of reducing the duration and discomfort associated with delivery. Two recent studies conducted in pregnant rats demonstrated that the cervix is highly responsive to relaxin during the antepartum period and that short-term subcutaneous administration of the hormone to relaxin-deficient animals not only promotes growth and softening of the cervix, but also reduces the duration of labor and delivery. Moreover, recent human clinical trials examining the influence of 24 weeks of continuous subcutaneous administration of recombinant human relaxin for the treatment of scleroderma provided evidence not only that the human reproductive tract is responsive to relaxin, but also that the administration of the hormone does not cause serious adverse side effects. It is concluded that recent findings provide an impetus for an investigation into relaxin's potential for cervical remodeling and facilitating birth in women.

Evaluation of glyceryl trinitrate, misoprostol, and prostaglandin E2 gel for preinduction cervical ripening in term pregnancy

AIM

To compare the efficacy of glyceryl trinitrate (GTN), dinoprostone and misoprostol for preinduction cervical ripening in primigravida at term.

METHODS

Sixty-five term primigravida, each with an unfavorable cervix (Bishop score </=5), were randomized to receive GTN (0.5 mg perivaginally, n = 21), dinoprostone gel (0.5 mg intracervically, n = 21) and misoprostol (50 microg perivaginally, n = 23) for a maximum of two doses, 6 h apart. Statistical analysis included paired t-tests to compare pre- and post-treatment Bishop scores, one-way analysis of variance (anova) tests to compare quantitative variables and chi-squared tests to compare the proportion of subjects achieving favorable Bishop scores.

RESULTS

Baseline Bishop scores were similar in the GTN (3.4 +/- 0.9), dinoprostone (3.4 +/- 1.0) and misoprostol groups (3.2 +/- 1.2). The final outcome was favorable (Bishop score >6) in a greater proportion of subjects in the misoprostol (n = 18, 81.8%) and dinoprostone (n = 14, 66.7%) groups compared with the GTN group (n = 11, 55%). In subjects with a severely unfavorable cervix (Bishop score </=3), treatment with misoprostol led to a favorable response in 61.6% of patients compared with 45.6% in the misoprostol group and 33.3% in the GTN group. A significant improvement was noted in the Bishop score of all three groups (P < 0.001) but the increase in Bishop score was greater in misoprostol (3.5 +/- 2.1) and dinoprostone groups (2.8 +/- 1.5), compared with the GTN group (2.0 +/- 1.0, ANOVA F = 4.8, P = 0.01). Hyperstimulation and tachysystole were observed only in the misoprostol (9% and 4.3%) and dinoprostone groups (4.7% and 16.2%). The most common adverse effect in the GTN group was headache, which was observed in 47.6% of this group's subjects.

CONCLUSION

The findings of the present study suggest that GTN is safer, but less efficacious, compared with prostaglandins for preinduction cervical ripening at term.

Second trimester abortion using isosorbide mononitrate in addition to gemeprost compared with gemeprost alone: a double-blind randomized, placebo-controlled multicenter trial

OBJECTIVE

We aimed to determine whether second-trimester abortion using isosorbide mononitrate (IMN) in addition to gemeprost is more effective and reduces side effects compared with gemeprost alone.

STUDY DESIGN

Eighty women who were age 13 to 23 weeks' gestation were randomly assigned to receive per vaginam either IMN 40 mg (group 1, 40 women) or placebo (group 2, 40 women) in addition to gemeprost 1 mg up to 3 times daily 3 hours apart for 2 days. Analysis of variance, a chi 2 test, and a multivariate analysis were performed.

RESULTS

Of the 72 women analyzed, 68% (group 1) and 38% (group 2) underwent abortion within day 1 (P < .05). However, group 1 was associated with more headache (18% of women) 3 hours after induction compared to group 2 (0% of women, P = .038).

CONCLUSION

IMN in addition to gemeprost is effective for second-trimester abortion, but is associated with more headache compared with gemeprost alone.

Obstetric implications of antepartum corticosteroid therapy for HELLP syndrome

OBJECTIVE

We reviewed the impact of intravenous high-dose corticosteroid administration for preterm hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome on vaginal delivery rate and degree of clinically significant thrombocytopenia.

METHODS

Retrospective analysis of 1991-2000 HELLP syndrome (platelets < 100,000/uL, lactate dehydrogenase > 600 IU/L, aspartate aminotransferase and/or alanine aminotransferase > 70 IU/L) data focusing on labor inductions for gestations of less than 34 weeks and increase in platelet count sufficient to permit regional anesthetic techniques.

RESULTS

Antepartum high-dose corticosteroid use increased from 32% (1991-1995) to 67% (1996-2000) for 350 patients studied (n = 199, < 34 weeks; n = 151, > 34 weeks). Corresponding vaginal delivery rates were 32% for gestations of less than 30 weeks, 61% at 30-31 weeks, and 62% at 32-33 weeks. Similarly, 27% of patients with a platelet count of less than 75,000/uL and 52% with a platelet count of less than 100,000/uL who received high-dose corticosteroids during the study interval subsequently achieved a 100,000/uL threshold in time to perform regional anesthesia for delivery.

CONCLUSION

Administration of intravenous high-dose corticosteroids for preterm HELLP syndrome increases probability of successful labor induction and candidacy for regional anesthesia.

LEVEL OF EVIDENCE

II-3.

Labor induction in women with an unfavorable Bishop score: randomized controlled trial of intrauterine Foley catheter with concurrent oxytocin infusion versus Foley catheter with extra-amniotic saline infusion with concurrent oxytocin infusion

OBJECTIVES

This study was undertaken to determine whether the addition of extra-amniotic saline infusion improves the efficacy of the Foley catheter in women undergoing cervical ripening and induction of labor with an unfavorable cervical examination.

STUDY DESIGN

One hundred consenting women with a Bishop score less than 5 with singleton gestation, intact membranes, vertex presentation, who required induction of labor were randomly assigned to 2 groups: Foley alone (Foley, n=49) or to the Foley catheter with extra-amniotic saline infusion (EASI, 30 mL of NS per hour infused through the distal port of the Foley, n=51). All women received concurrent dilute oxytocin infusion per protocol. The primary analysis was intent to treat. Nonparametric tests were used as indicated.

RESULTS

At randomization, the groups were well balanced for potential confounders including: parity, gestational age, prior cesarean delivery, preeclampsia, mean dilation, effacement, and Bishop score. There were no differences between the groups for time to delivery (Foley 17.7 +/- 10.5 hours vs EASI 17.4 +/- 11.7 hours, P=.9), the proportion of women delivered before 24 hours (Foley 41/49 [84%] vs EASI 39/51 [77%], P=.37) or cesarean rates (Foley 9/49 [17.7%] vs EASI 9/51 [18.4%], P=.92). There were also no differences in complications, including chorioamnionitis, endometritis, and neonatal morbidity.

CONCLUSION

EASI does not increase the efficacy of cervical ripening and induction of labor with a Foley catheter and concurrent oxytocin infusion.

Randomized trial between two active labor management protocols in the presence of an unfavorable cervix

OBJECTIVE

The purpose of this study was to compare the efficacy of two protocols for active management of labor at term in the presence of an unfavorable cervix.

STUDY DESIGN

Pregnancies that underwent labor induction at > or =37 weeks of gestation with an unfavorable cervix (Bishop score, < or =6) were randomly assigned to receive vaginally either a single dose of sustained-release dinoprostone (Cervidil) with concurrent low-dose oxytocin or multidosing of misoprostol (25 microg every 4 hours) followed by high-dose oxytocin. The primary outcome was the time interval from induction to vaginal delivery. Other parameters included excess uterine activity and cesarean delivery rates.

RESULTS

A total of 151 patients (dinoprostone, 74 patients; misoprostol, 77 patients) were enrolled. The mean time from the initiation of induction to vaginal delivery was the same in the dinoprostone and misoprostol groups (15.7 hours; 95% CI, 13.7-17.7 hours vs 16.0 hours; 95% CI, 14.1-17.8 hours; P=.34), regardless of parity. The dinoprostone and misoprostol groups did not differ statistically in the percent of patients who were delivered vaginally by 12 hours (36.2% vs 29.7%), 18 hours (63.8% vs 56.3%), and 24 hours (81.0% vs 81.3%). Excess uterine activity was not more common in either group, and hyperstimulation syndrome was absent in all cases. Primary cesarean delivery rates were similar (dinoprostone, 21.6%; misoprostol, 16.9%; relative risk, 1.3; 95% CI, 0.7-2.5), with a failed induction that occurred in one case in each group.

CONCLUSION

Sustained-release dinoprostone with concurrent low-dose oxytocin and intermittent misoprostol with delayed high-dose oxytocin are effective alternatives for active management of labor with an unfavorable cervix.

Trends and Issues in Labor Induction in the United States: Implications for Clinical Practice

The labor induction rate is at an all-time high in the United States. Although induction of labor is recommended as a therapeutic option only when the benefits of expeditious birth outweigh the risks of continuing the pregnancy, a "psychosocial indication" has become a common rationale for elective induction in the United States. It is unlikely that all women are provided with a complete discussion of the cascade of interventions that frequently accompany labor induction and the risks of cesarean birth. Although at first glance elective labor induction may seem more convenient, an appreciation of the inconvenience of the greater rates of interventions, the longer labor and overall hospital stay, the higher costs, the additional attention required by the primary health care provider when complications occur, and the risk of an adverse outcome for a mother or baby after an elective procedure with subsequent litigation should cause everyone to exercise caution and reevaluate current practice. Professional organizations should take proactive steps to advocate for pregnant women so they are fully aware of the risks and benefits. A public campaign to discourage elective labor induction for nulliparous women is worth serious consideration.

Induction of labour with an unfavourable cervix

Labour induction is undertaken when the advantages for the mother and/or the baby are considered to outweigh the disadvantages. When the uterine cervix is unfavourable, oxytocin, with or without amniotomy, is frequently ineffective. Vaginal prostaglandin E(2) is most commonly used if it is affordable. Evidence regarding many alternative methods is discussed in this chapter. Of particular interest are misoprostol and extra-amniotic saline infusion.Misoprostol, an orally active prostaglandin E(1) analogue, has been used widely by the vaginal and oral routes for labour induction at or near term. Several recent trials have confirmed that it is highly effective. Overall Caesarean section rates appear to be reduced, despite a relative increase in Caesarean sections for fetal heart rate abnormalities. Concern remains regarding increased rates of uterine hyperstimulation and meconium-stained amniotic fluid, although data on perinatal outcome have been reassuring. Postpartum haemorrhage may be increased following labour induction with misoprostol, and isolated reports of uterine rupture, with or without previous Caesarean section, have appeared. Using small dosages appears to reduce adverse outcomes. Very large trials are needed to evaluate rare adverse outcomes.Extra-amniotic saline infusion is an effective method which appears to reduce the risk of uterine hyperstimulation that occurs with the use of exogenous uterotonics.