In vitro response of prostaglandin E2 receptor (EP3) in the term pregnant rat uterus and cervix to misoprostol

A new trick for an old dog? Myocardial-specific roles for prostaglandins as mediators of ischemic injury and repair

The small lipid-derived paracrine signaling molecules known as prostaglandins have been recognized for their ability to modulate many facets of cardiovascular physiology since their initial discovery more than 85 years ago. Although the role of prostaglandins in the vasculature has gained significant attention across time, a handful of historical studies have also directly implicated the cardiomyocyte in both prostaglandin synthesis and release. Recently, our understanding of how prostaglandin receptor modulation impacts and contributes to myocardial structure and function has gained attention while leaving most other components of myocardial prostaglandin metabolism and signaling unexplored. This mini-review highlights both the key historical studies that underpin modern prostaglandin research in the heart, while concurrently presenting the latest findings related to how prostaglandin metabolism and signaling impact myocardial injury and repair.

Clinical Insights for Cervical Ripening and Labor Induction Using Prostaglandins

Cervical ripening is often the first component of labor induction and is used to facilitate the softening and thinning of the cervix in preparation for labor. Common methods used for cervical ripening include both mechanical (e.g., Foley or Cook catheters) and pharmacologic (e.g., prostaglandins) methods. The choice of method(s) for ripening should take into account the patient's medical and obstetric history, clinical characteristics, and risk of adverse effects if uterine tachysystole were to occur. In this narrative review, we highlight the differences between the prostaglandins dinoprostone and misoprostol with respect to pharmacology and pharmacokinetics, efficacy, and potential safety concerns. Practical guidance on choosing an appropriate prostaglandin agent for cervical ripening and labor induction is provided via the use of clinical vignettes. Considering the advantages and disadvantages of each preparation allows clinicians to individualize treatment, depending on the indications for induction and unique characteristics of each patient.

Is low dose vaginal misoprostol better than dinoprostone gel for induction of labor: a randomized controlled trial

OBJECTIVE

To compare the efficacy and safety profile of low dose vaginal misoprostol with dinoprostone gel for induction of labor in term pregnancies.

METHODS

The study was conducted at Lady Hardinge Medical College and Smt Sucheta Kriplani Hospital on 100 pregnant women with term pregnancy after application of inclusion and exclusion criteria. The women were randomized in 2 groups of 50 women each. Group I received misoprostol 25μg at every six hour vaginally for a maximum of five doses for induction of labor; while group II received dinoprostone gel 0.5 mg every six hourly for a maximum of three doses. Maternal outcomes such as mode of delivery and induction delivery interval; and fetal outcomes such as APGAR score and incidence of NICU admission were assessed in both the groups. Statistical analysis was done using student t-test and chi-square test.

RESULTS

There was no significant difference in the mean induction to delivery interval in both the groups (14.32±0.13 hours in Group I and 14.92±0.18 hours in Group II, p=0.75), mode of delivery, indication of cesarean section and perinatal outcome. However, significant difference was observed in requirement of oxytocin augmentation in both the groups (32% in Group I and 68% in Group II, p=0.005).

CONCLUSION

Vaginal misoprostol in low doses is similar in efficacy and safety to dinoprostone gel for cervical ripening and labor induction in term pregnancy.

Shortening the induction delivery interval with prostaglandins: a randomized controlled trial of solo or in combination

OBJECTIVE

To compare the efficacy and safety of misoprostol alone with dinoprostone followed by misoprostol, all inserted intravaginally in induction of labor at term and the obstetrical outcome.

MATERIAL AND METHODS

A pilot study comprising 111 primigravidae, >37 gestational weeks with singleton pregnancy in cephalic presentation having an unfavorable Bishop score admitted for labor induction, were considered and randomly allocated into two groups. In group I (n=55) with intravaginal 25mcg misoprostol 4 hourly (six doses at the most) and and group II (n=56), with dinoprostone 0.5mg followed eight hours later by 25mcg misoprostol induction to vaginal delivery time was found to be significantly different, being 14.8 h in group-I and shorter in group-II with a mean of 11.6 h. Vaginal delivery rates within 12 h (groups-I and -II: 47.2%, as compared to 60.7%, respectively) were found to be higher with dinoprostone-misoprostol induction, as well as vaginal delivery rates in 24 h, 80.0% and 91.1%. The need for oxytocin augmentation was more frequent in the misoprostol than in the dinoprostone-misoprostol group, (61.8%, and 39.3%), and all these observations were statistically significant. Abnormal foetal heart rate pattern occurred more frequently (18.2%) in group-I in contrast to 5.3% in group-II, as was the incidence rate of (18.2%) who had passage of meconium in group-I, this rate being significantly different from group-II having meconium passage in 3 cases, a rate of 5.3%.

CONCLUSION

Using dinoprostone followed by vaginal misoprostol is safe and effective for induction of labor with less need for oxytocin augmentation and shorter induction delivery interval.

Efficacy and safety of six hourly vaginal misoprostol versus intracervical dinoprostone: a randomized controlled trial

OBJECTIVE

To compare the efficacy and safety of intravaginal misoprostol versus dinoprostone cervical gel for cervical ripening and labour induction.

METHODS

We carried out an experimental clinical trial in which we enrolled 130 cervical consecutive patients with cervical ripening, randomly assigned to one of the following two treatment groups: (1) intravaginal misoprostol and (2) intracervical dinoprostone gel. A total of 50 microm of misoprostol was placed in the posterior vaginal fornix every 6 h for a maximum period of 24 h and 0.5 mg of dinoprostone was administrated in the uterine cervix every 6 h, for a maximum period of 24 h. The primary outcome measure was the number (rate) of women who went to vaginally deliver within 24 h of the protocol initiation.

RESULTS

Among 130 patients evaluated, 65 were allocated to the misoprostol group and 65 to the dinoprostone group. The proportion of vaginal delivery within 24 h was significantly higher in the misoprostol group (75%) than in the dinoprostone group (53.8%) (RR = 1.40, 95% CI [1.07-1.45], P = 0.02). There was no significant difference between the mean time interval of delivery in the misoprostol group and the dinoprostone group (14.9 vs.15.8 h) (P = 0.51). The Bishop score was significantly higher in the misoprostol group, 6 h after the onset of the study (1.38; relative risk, 95% CI [1.02-1.85], P = 0.03). The Caesarean delivery rate for fetal distress was higher in the dinoprostone group (21 vs. 10.8%, P = 0.15). The tachysystole (Misoprostol 6.1% vs. dinoprostone 4.6%, relative risk 1.15, 95% CI [0.6-2.24]) and hyperstimulation syndrome rates (Misoprostol 7.6% vs. dinoprostone 4.6%, relative risk 1.26, 95% CI [0.72-2.24]) were slightly increased in the misoprostol group than in the dinoprostone group without reaching the level of statistical signification.

CONCLUSION

Misoprostol as used in this protocol is more effective than cervical dinoprostone gel application in the cervical ripening and labour induction. There is a tendency for an increase in the rate of tachysystole and hyperstimulation syndrome.

Misoprostol induces cervical nitric oxide release in pregnant, but not in nonpregnant, women

OBJECTIVE

The cells of the human uterine cervix synthesize nitric oxide, which may be a factor in cervical ripening. We studied the effect of misoprostol on cervical nitric oxide release in nonpregnant and pregnant women.

STUDY DESIGN

Seventy-two nonpregnant (n=15) and pregnant (n=57; 26 in early pregnancy, 31 in late pregnancy) women were treated with either vaginal misoprostol (n=54) or vaginal placebo (n=18). The dose of misoprostol was 400 mug in nonpregnant and early pregnancy group, and 25 mug in late pregnancy group. Serial cervical fluid samples, collected before and up to 3 hours after misoprostol/placebo, were assessed for the concentration of nitric oxide metabolites by means of the Griess reaction.

RESULTS

Placebo had no effect on cervical fluid nitric oxide metabolite level. In 1 to 3 hours, misoprostol induced 4.3- to 5.2-fold elevations in cervical fluid Nox concentrations in early pregnancy (P < .01), and 4.4- to 18.2-fold elevations in late pregnancy (P < .01), but these responses did not differ significantly from each other. Misoprostol had no effect on cervical fluid nitric oxide metabolites in nonpregnant women. There was a trend towards a relationship between cervical nitric oxide stimulation after misoprostol and cervical ripening.

CONCLUSION

Vaginal misoprostol stimulates cervical nitric oxide release in pregnancy. This suggests a joint action of nitric oxide and prostaglandins in cervical ripening.

Expression of prostaglandin transporter in the bovine uterus and fetal membranes during pregnancy

Uteroplacental prostaglandins (PGs) play pivotal roles in the maintenance and termination of pregnancy in mammals. In the present study, we have characterized the expression of prostaglandin transporter (PGT) in placentome caruncles, intercaruncular tissues, fetal membranes, and utero-ovarian plexus during pregnancy in cattle. Pregnant bovine uteri were collected and classified into six groups covering the entire gestational length. In caruncles and intercaruncular tissues, PGT mRNA (also known as SLC02A1) and PGT protein were highly expressed at the late stage of pregnancy compared to the early and mid stages, whereas the level of expression is constant and low in fetal membranes throughout pregnancy. PGT mRNA and PGT protein were expressed at a constant level in the utero-ovarian plexus both ipsilateral and contralateral to corpus luteum throughout the course of pregnancy. Overall, the relative expression of PGT mRNA and PGT protein were higher in caruncles than in intercaruncular tissue and fetal membranes, whereas no differences were detected between intercaruncular tissues and fetal membranes at any stage of gestation. Immunohistochemistry indicated that PGT was preferentially expressed in caruncular epithelial cells of placentomes and endometrial luminal epithelial and myometrial smooth muscle cells of the intercaruncular regions. The level of PGT expression was comparatively higher in maternal components than in fetal components. In conclusion, differential spatiotemporal tissue-specific expression of PGT in uterine and intrauterine tissues suggests a role for this transporter in the exchange of PGs between the maternal and the fetal compartments, as well as for intrauterine metabolism of PGs during pregnancy.

Comparison of misoprostol and dinoprostone for elective induction of labour in nulliparous women at full term: a randomized prospective study

BACKGROUND

The objective of this randomized prospective study was to compare the efficacy of 50 mcg vaginal misoprostol and 3 mg dinoprostone, administered every nine hours for a maximum of three doses, for elective induction of labor in a specific cohort of nulliparous women with an unfavorable cervix and more than 40 weeks of gestation.

MATERIAL AND METHODS

One hundred and sixty-three pregnant women with more than 285 days of gestation were recruited and analyzed. The main outcome measures were time from induction to delivery and incidence of vaginal delivery within 12 and 24 hours. Admission rate to the neonatal intensive care unit within 24 hours post delivery was a secondary outcome.

RESULTS

The induction-delivery interval was significantly lower in the misoprostol group than in the dinoprostone group (11.9 h vs. 15.5 h, p < 0.001). With misoprostol, more women delivered within 12 hours (57.5% vs. 32.5%, p < 0.01) and 24 hours (98.7% vs. 91.4%, p < 0.05), spontaneous rupture of the membranes occurred more frequently (38.8% vs. 20.5%, p < 0.05), there was less need for oxytocin augmentation (65.8% vs. 81.5%, p < 0.05) and fewer additional doses were required (7.5% vs. 22%, p < 0.05). Although not statistically significant, a lower Caesarean section (CS) rate was observed with misoprostol (7.5% vs. 13.3%, p > 0.05) but with the disadvantage of higher abnormal fetal heart rate (FHR) tracings (22.5% vs. 12%, p > 0.05). From the misoprostol group more neonates were admitted to the intensive neonatal unit, than from the dinoprostone group (13.5% vs. 4.8%, p > 0.05). One woman had an unexplained stillbirth following the administration of one dose of dinoprostone.

CONCLUSIONS

Vaginal misoprostol, compared with dinoprostone in the regimens used, is more effective in elective inductions of labor beyond 40 weeks of gestation. Nevertheless, this is at the expense of more abnormal FHR tracings and more admissions to the neonatal unit, indicating that the faster approach is not necessarily the better approach to childbirth.