Misoprostol for labour induction

Comparison of two labor induction regimens with intravaginal misoprostol 25 μg and adverse perinatal outcomes

OBJECTIVE

The aim of the study was to compare two labor induction regimens (4 and 6 h), to determine predictors of successful labor induction with intravaginal misoprostol 25 μg tablets, and to evaluate the association with adverse perinatal outcomes.

METHODS

This was a retrospective cohort study that included singleton pregnancies undergoing induction of labor with an intravaginal misoprostol 25 μg tablet between 37 and 42 weeks of gestation. The pregnant women were divided into two groups: Group 1-intravaginal misoprostol 25 μg every 4 h and Group 2-intravaginal misoprostol 25 μg every 6 h.

RESULTS

Pregnant women were divided into Group 1 (n=289) and Group 2 (n=278). Group 1 had a higher median number of intravaginal misoprostol 25 μg tablets (3.0 vs. 2.0 tablets, p<0.001), a lower prevalence of postpartum hemorrhage (7.6 vs. 32.7%, p<0.001), and a higher need for oxytocin (odds ratio [OR]: 2.1, 95%CI: 1.47-2.98, p<0.001) than Group 2. Models including intravaginal misoprostol 25 μg tablets every 4 and 6 h [x2(1)=23.7, OR: 4.35, p<0.0001], parity [x2(3)=39.4, OR: 0.59, p=0.031], and Bishop's score [x2(4)=10.8, OR: 0.77, p=0.019] were the best predictors of failure of labor induction. A statistically significant difference between groups was observed between the use of the first intravaginal misoprostol 25 μg tablet at the beginning (Breslow p<0.001) and the end of the active labor phase (Long Hank p=0.002).

CONCLUSION

Pregnant women who used intravaginal misoprostol 25 μg every 4 h had a longer time from the labor induction to the beginning of the active phase of labor and higher rates of adverse perinatal outcomes than women who used intravaginal misoprostol 25 μg every 6 h.

The Efficacy of Misoprostol Vaginal Inserts for Induction of Labor in Women with Very Unfavorable Cervices

BACKGROUND

The purpose of the present study was to evaluate the effectiveness of a misoprostol vaginal insert as an induction-of-labor (IOL) agent in women with an unfavorable cervix (Bishop score < 2) in achieving vaginal delivery (VD) within 48 h, depending on the gestational week, with particular emphasis on the cesarean section (CS) percentage, intrapartum analgesia application and possible side effects, such as tachysystole ratio.

METHODS

In this retrospective observational study involving 6000 screened pregnant patients, 190 women (3%) fulfilled the study inclusion criteria and underwent vaginal misoprostol IOL. The pregnant women were collected into three groups: patients who delivered at up to 37 weeks of gestation (<37 Group)-42 patients; patients who delivered between 37 and 41 weeks of gestation (37-41 Group)-76 patients; and patients who delivered after 41 weeks of gestation (41+ Group)-72 patients. The outcomes included time to delivery and mode of delivery, rate of tachysystole, need for intrapartum analgesia, and need for oxytocin augmentation.

RESULTS

Most of the patients delivered vaginally (54.8% in <37 Group vs. 57.9% in 37-41 Group vs. 61.1% in 41+ Group). A total of 89.5% (170/190) of patients delivered within 48 h (<37 Group-78.6% vs. 37-41 Group-89.5% vs. 41+ Group-95.8%). Statistical significance was demonstrated for the increased rate of vaginal deliveries and shortened time to delivery in the 41+ weeks group (p = 0.0026 and p = 0.0038). The indications for cesarean section were as follows: abnormal CTG pattern vs. lack of labor progression: 42.1% vs. 57.9% in <37 Group, 59.4% vs. 40.6% in 37-41 Group and 71.4% vs. 28.6% in 41+ Group. Statistical significance was demonstrated for the increased rate of abnormal CTG patterns as cesarean section indications in the 41+ Group (p = 0.0019). The need for oxytocin augmentation in each group was: 35.7% in <37 Group vs. 19.7% in 37-41 Group vs. 11.1% in 41+ Group. Statistical significance was shown for decreased need for oxytocin augmentation in +41 Group (p = 0.0016). The need for intrapartum anesthesia, depending on the group, was: 78.6% in <37 Group vs. 82.9% in 37-41 Group vs. 83.3% in 41+ Group. Statistical significance was demonstrated for increased need for intrapartum anesthesia application during labor in +41 Group (p = 0.0018). The prevalence of hyperstimulation was similar in all three groups (4.8% vs. 7.9% vs. 5.6% p > 0.05).

CONCLUSIONS

The misoprostol vaginal regimen for IOL used in our study is effective in achieving vaginal delivery within 48 h. In post-term women, the use of this regimen is characterized by an increased rate of vaginal deliveries, a shorter time to delivery and a lower need for oxytocin.

Pharmacokinetics and Bioequivalence of Misoprostol Tablets: An Open-Label, Randomized, Single-dose, Crossover Study With Healthy Chinese Volunteers

Misoprostol is a synthetic prostaglandin E1 derivative that has been used to treat duodenal and gastric ulcers, and to prevent ulcers caused by nonsteroidal anti-inflammatory drugs in many countries. Misoprostol can also be used for medical abortion. This study aimed to investigate the pharmacokinetic profiles of misoprostol tablets (test product) by comparing them with Cytotec (200 μg) (reference product). To assess the bioequivalence between test and reference products, a two-sequence, two-period crossover study was conducted with 48 healthy Chinese subjects enrolled under fasting conditions. A validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) assay was used to determine the concentration of misoprostol acid in plasma. A mixed model analysis of variance was used to calculate the bioequivalence of pharmacokinetic (PK) parameters. The point estimate of geometric mean ratios with 90% confidence intervals for the maximum observed concentration (C_max ) and the area under the concentration-time curve (AUC_0-t ) for misoprostol acid in reference and test products were 107.8% and 106.5%, respectively (range 80%-125%). Additionally, none of the secondary PK parameters presented significant differences. No severe or more than moderate adverse events were detected in the 48 subjects. However, one subject discontinued the treatment due to drug-related gastrointestinal reactions. All adverse events were mild with rates of 19.2% and 22.9% after the administration test and reference products, respectively. Overall, the bioequivalence between the two misoprostol products was demonstrated in fasting conditions, and all subjects tolerated both treatments.

Cervical ripening and labour induction: A critical review of the available methods

Induction of labour is one of the most common interventions experienced by pregnant women. There are two overlapping components to labour induction, which include cervical ripening and the initiation of regular contractions. A large number of clinical studies have been conducted for evaluating the methods used for induction of labour, their effectiveness and safety, and pregnancy outcomes. Randomised controlled trials (RCTs) provide the strongest form of evidence for clinical practice. These data are brought together in systematic reviews and have been incorporated into national and international guidelines. Despite this, there is considerable variation in the recommendations between guidelines. Heterogeneity between studies, inconsistency in the definitions of trial outcomes, and underpowered sample size contribute to the difficulty in making robust recommendations. There are pharmacological and non-pharmacological approaches that can be compared with each other and with placebo or no treatment. There are also complementary therapies that may appeal to women but lack evidence of their effectiveness. These issues have been addressed in the current chapter, with a critical review of the research evidence presented in clinical trials and systematic reviews.