Does the route of administration of misoprostol make a difference? The uterotonic effect and side effects of misoprostol given by different routes after vaginal delivery

Refractory uterine atony: still a problem after all these years

Postpartum hemorrhage is a leading cause of maternal morbidity and mortality, and uterine atony is the leading cause of postpartum hemorrhage. Risk factors for uterine atony include induced or augmented labor, preeclampsia, chorio-amnionitis, obesity, multiple gestation, polyhydramnios, and prolonged second stage of labor. Although a risk assessment is recommended for all parturients, many women with uterine atony do not have risk factors, making uterine atony difficult to predict. Oxytocin is the first-line drug for prevention and treatment of uterine atony. It is a routine component of the active management of the third stage of labor. An oxytocin bolus dose as low as 1 IU is sufficient to produce satisfactory uterine tone in almost all women undergoing elective cesarean delivery. However, a higher bolus dose (3 IU) or infusion rate is recommended for women undergoing intrapartum cesarean delivery. Carbetocin, available in many countries, is a synthetic oxytocin analog with a longer duration than oxytocin that allows bolus administration without an infusion. Second line uterotonic agents include ergot alkaloids (ergometrine and methylergonovine) and the prostaglandins, carboprost and misoprostol. These drugs work by a different mechanism to oxytocin and should be administered early for uterine atony refractory to oxytocin. Rigorous studies are lacking, but methylergonovine and carboprost are likely superior to misoprostol. Currently, the choice of second-line agent should be based on their adverse effect profile and patient comorbidities. Surgical and radiologic management of uterine atony includes uterine tamponade using balloon catheters and compression sutures, and percutaneous transcatheter arterial embolization.

Misoprostol for open myomectomy: a systematic review and meta-analysis of randomised control trials

BACKGROUND

Excessive blood loss is a significant risk of myomectomy with the potential need for hysterectomy.

OBJECTIVE

To study the effectiveness of preoperative misoprostol compared with placebo at open myomectomy on intra- and postoperative outcomes.

SEARCH STRATEGY

PubMed, Cochrane, Scopus, MEDLINE and EMBASE.

SELECTION CRITERIA

Randomised control studies of women undergoing open myomectomy for symptomatic fibroids who were given either misoprostol or placebo preoperatively.

DATA COLLECTION AND ANALYSIS

The revised Cochrane risk-of-bias tool for randomised trials was used to assess the risk of bias. Primary outcomes were blood loss, drop in haemoglobin and need for blood transfusion. Secondary outcomes were operative time, postoperative pyrexia and length of postoperative stay. Pooled effect sizes with corresponding 95% CI were calculated using random effects models. Data were analysed using two statistical models for statistical reliability.

RESULTS

Eight studies were included with a total of 385 patients, of which 192 received misoprostol. Preoperative misoprostol was significantly associated with lower blood loss by -170.32 ml (95% CI -201.53 to -139.10), lower drop in haemoglobin by -0.48 g/dl (95% CI -0.65 to -0.31), reduced need for blood transfusion (odds ratio [OR] -0.48, 95% CI -0.65 to -0.31), and a reduction in operative time by -11.64 minutes (95% CI -15.73 to -7.54). There was no difference in postoperative pyrexia or length of postoperative stay.

CONCLUSION

Moderate- to high-quality studies have established that misoprostol minimises blood loss and need for blood transfusion at open myomectomy. This low-cost and readily available drug should be routinely administered prior to open myomectomy to improve clinical outcomes.

TWEETABLE ABSTRACT

Use of misoprostol at open myomectomy reduces blood loss and need for blood transfusion with no impact on postoperative pyrexia.

A Relative Bioavailability Study of Two Misoprostol Formulations Following a Single Oral or Sublingual Administration

Introduction

Misoprostol (Cytotec) was primarily made for treating gastric ulcers. However today it is mostly used for abortion, treating postpartum hemorrhage, and for induction of labor. The tablet contains 200 µg of misoprostol, yet the dosages used for induction of labor are much smaller (25–50 µg), leading to uncertainty of dosage in daily use.

Aim

To evaluate and compare the relative bioavailability of two misoprostol products (Angusta 25 µg and Cytotec 200 µg tablets) administered orally or sublingually given in a daily clinical setting to women admitted for induction of labor at term.

Methods

Women carrying a live, singleton fetus in a cephalic position and with a gestational age between 259 and 296 days were included. Blood samples were collected at 0, 5, 10, 20, 30, 40, 50, 75, 100, 120, 180, and 240 minutes. A serum analytical assay was performed and pharmacokinetic parameters were calculated. Patients were assigned to one of three groups.

Results

A total of 72 patients were included. No significant differences demographic characteristics were found. The ratios for AUC, AUC (_0−t), and C_max were similar in all three groups, but CI-values were outside the required 80–125%. Sublingual administration yielded a 20–30% higher bioavailability and a 50% higher C_max than compared to the oral route.

Conclusion

The relative bioavailability between Angusta and Cytotec could not be confirmed as being equal at the 25 µg or 50 µg level because the 90% CI-values when comparing the ratios for AUC, AUC_(0−t), and C_max were wider than accepted. The reason for this could be the real-life, non-standardized circumstances in which the study was conducted. Sublingual administration seems to have higher bioavailability than oral administration. More studies are needed to ascertain an optimal dosage regime balancing both safety and efficacy for mother and child.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier NCT02516631.

Comparison of rectal misoprostol's effect when used before and after a cesarean section on post-cesarean bleeding

OBJECTIVE

Cesarean section is a common surgery in women. Different drugs are used to control its bleeding. This study compared the effect of using rectal misoprostol before and after surgery on the amount of post-cesarean bleeding.

MATERIALS AND METHODS

A number of 120 women who were admitted to our hospital because of elective cesarean section entered this clinical trial. They were divided into two groups. The first (before surgery) group received 400μg of rectal misoprostol before the cesarean section and the second (after surgery) group after the surgery. The amount of bleeding was measured in both groups. The data were recorded and analyzed.

RESULTS

Their mean of age was 29.1±6.1 years old. The mean of blood loss volume was 283±147mL in the before-surgery group and 294±108mL in the after-surgery group (P=0.6). There was no significant difference in the level of post-operation hemoglobin between the two groups. However, the frequency of need for additional uterotonics was 47% in the first group and 85% in the second group (P<0.001).

CONCLUSION

There seems to be no significant difference in administering rectal misoprostol before or after the surgery, but the need for additional uterotonics is reduced if it is used before the surgery.

Individualized misoprostol dosing for labor induction or augmentation: A review

Cesarean birth rates are greater than 20% in many developed countries. The main diagnoses contributing to the high rate of cesarean births in nulliparous women are dystocia and prolonged labor. Traditionally, a policy of vaginal dinoprostone for the treatment of unripe cervix or early amniotomy with oxytocin administration for a ripened cervix has been associated with a modest reduction in the rate of cesarean births due to arrest disorders. However, the course of vaginal dinoprostone is tedious and oxytocin should be administered through an infusion pump, which may be inconvenient in certain settings. Because misoprostol has powerful uterotropic and uterotonic effects, and has become a common agent used in the practice of obstetrics and gynecology, the United States Food and Drug Administration removed the absolute contraindication of the drug during pregnancy from its label in April 2002. However, excessive uterine contractility resulting in tachysystole or fetal distress is always a concern with the oral or vaginal use of fixed-dosage misoprostol. Therefore, misoprostol should be administered with caution to ensure that fetal hypoxia does not occur. A pilot trial examining the use of very small, frequent, titrated oral misoprostol dosages administered every 2 h was first conducted by Hofmeyr et al in 2001. Given women’s different metabolisms and responses to misoprostol, another method of titrating individualized oral misoprostol with dosing administered every hour relative to uterine response was then developed by Cheng in 2006. Based on previous studies, this titration method is potentially an ideal alternative to traditional dinoprostone, oxytocin or the previously established misoprostol dosing method for labor induction or augmentation.

No reduction of manual removal after misoprostol for retained placenta: a double-blind, randomized trial

OBJECTIVE

To test the effect of 800 μg of misoprostol orally on the prevention of manual removal of retained placenta.

DESIGN

Multicenter, double-blinded, placebo-controlled, randomized trial.

SETTING

One university and one non-university teaching hospital in the Netherlands.

SAMPLE

99 women with retained placenta (longer than 60 min after childbirth) in the absence of postpartum hemorrhage.

METHODS

Eligible women were administered either 800 μg of misoprostol or placebo orally.

MAIN OUTCOME MEASURES

Number of manual removals of retained placenta and amount of blood loss.

RESULTS

Manual removal of retained placenta was performed in 50% of the women who received misoprostol and in 55% who received placebo (relative risk 0.91, 95% confidence interval 0.62-1.34). No difference in the amount of blood loss (970 vs. 1120 mL; p = 0.34) was observed between the two groups.

CONCLUSIONS

Administration of 800 μg of oral misoprostol, one hour after childbirth, does not seem to reduce the number of manual removals of retained placentas. The time elapsing results in the delivery of 50% of the retained placentas at the expense of an increased risk of postpartum hemorrhage.

Dose and side effects of sublingual misoprostol for treatment of postpartum hemorrhage: what difference do they make?

Background

Shivering and fever are common side effects of misoprostol. An unexpectedly high rate of fever above 40°C was documented among Ecuadorian women given treatment with 800mcg of sublingual misoprostol to manage postpartum hemorrhage (PPH) (36%). Much lower rates have been reported elsewhere (0-9%).

Methods

From February to July 2010, an open-label pilot study was conducted in Quito, Ecuador to determine whether a lower dose--600mcg sublingual misoprostol--would result in a lower incidence of high fever (≥40°C). Rates of shivering and fever with 600mcg sublingual regimen were compared to previously documented rates in Ecuador following PPH treatment with 800mcg sublingual misoprostol.

Results

The 600mcg dose resulted in a 55% lower rate of high fever compared with the 800mcg regimen (8/50; 16% vs. 58/163; 36%; relative risk 0.45 95% CI 0.23-0.88). Only one woman had severe shivering following the 600mcg dose compared with 19 women in the 800mcg cohort (2% vs. 12%; relative risk 0.17 (0.02-1.25)). No cases of delirium/altered sensorium were reported with the 600mcg dose and women’s assessment of severity/tolerability of shivering and fever was better with the lower dose.

Conclusions

600mcg sublingual misoprostol was found to decrease the occurrence of high fever among Ecuadorian women when given to treat PPH. This study however was not powered to examine the efficacy of this treatment regimen and cannot be recommended at this time. Future research is needed to confirm whether other populations, outside of Quito, Ecuador, experience unusually high rates of elevated body temperature following sublingual administration of misoprostol for treatment of PPH. If indeed similar trends are found elsewhere, larger trials to confirm the efficacy of lower dosages may be justified.

Trial Registration

Clinical trials.gov, Registry No. NCT01080846

Uterine activity during the third stage of labor

INTRODUCTION

The purpose of this study was to evaluate the use of intrauterine pressure catheters (IUPCs) to measure uterine activity during the third stage of labor.

METHODS

The study was conducted in a tertiary-care center. All births were attended by certified nurse-midwives. Low-risk pregnant women at term gestation had intrauterine monitoring attempted during the third stage of labor. Data were analyzed using descriptive statistics and analysis of variance.

RESULTS

Of the 36 women in the study, 19 had clear contractions recorded, 4 had unclear contractions, and 13 had flat tracings. The IUPC was useful for measuring uterine activity in a small number of women during the third stage of labor. When measured, uterine contractions were variable in strength and frequency.

DISCUSSION

Intrauterine pressure catheters can be used as a measurement of uterine activity during the third stage of labor and should be considered for future research about third-stage physiology. Further work is needed to determine the best procedure for placement, and IUPC use before expulsion of the placenta will not be useful in all women. Effective measurement of uterine activity may guide future research on interventions to reduce the risk of postpartum hemorrhage.

Comparison of labor induction with titrated oral misoprostol solution between nulliparous and multiparous women

AIM

To compare the outcomes of labor induction with oral misoprostol solution between nulliparous and multiparous women.

METHODS

We retrospectively reviewed the medical records of all patients between 37 and 42 weeks of gestation with a Bishop score <or=6 who underwent labor induction with titrated oral misoprostol solution. The women were allocated into two groups: nulliparous and multiparous. The women received one basal unit of misoprostol solution (20 mL, 1 microg/mL) every hour for four doses; additional doses were titrated against individual uterine response. The interval of latent and active phase and vaginal delivery within 12 h were the primary outcomes.

RESULTS

Of the 112 women included in the study, 49 (43.8%) mulliparae and 63 (56.2%) multiparae underwent labor induction with titrated oral misoprostol solution. Complete vaginal delivery occurred within 12 h in 21 (42.9%) nulliparae and 54 (85.7%) multiparae (RR, 0.54; 95% CI, 0.39-0.76). All induction intervals, including the latent and active phases, were significantly shorter in the multiparous group (P < 0.01). Induction failure did not occur in any patient in either of the groups. There were no instances of hyperstimulation, which was defined as tachysystole or hypertonus with nonreassuring fetal heart rate pattern, although tachysystole, defined as the presence of at least six contractions in 10 min over at least two 10-min windows, occurred in four (8.2%) nulliparous women and in four (6.3%) multiparous women. Hypertonus, defined as a single contraction lasting more than 2 min, did not occur in either group. None of the neonates in either group had an Apgar score of <7 at 1 min.

CONCLUSION

Titrated oral misoprostol solution is a promising method of labor induction for both nulliparous and multiparous women.

Misoprostol as an adjunct to standard uterotonics for treatment of post-partum haemorrhage: a multicentre, double-blind randomised trial

BACKGROUND

Post-partum haemorrhage is a leading cause of global maternal morbidity and mortality. Misoprostol, a prostaglandin analogue with uterotonic activity, is an attractive option for treatment because it is stable, active orally, and inexpensive. We aimed to assess the effectiveness of misoprostol as an adjunct to standard uterotonics compared with standard uterotonics alone for treatment of post-partum haemorrhage.

METHODS

Women delivering vaginally who had clinically diagnosed post-partum haemorrhage due to uterine atony were enrolled from participating hospitals in Argentina, Egypt, South Africa, Thailand, and Vietnam between July, 2005, and August, 2008. Computer-generated randomisation was used to assign women to receive 600 microg misoprostol or matching placebo sublingually; both groups were also given routine injectable uterotonics. Allocation was concealed by distribution of sealed and sequentially numbered treatment packs in the order that women were enrolled. Providers and women were masked to treatment assignment. The primary outcome was blood loss of 500 mL or more within 60 min after randomisation. Analysis was by intention to treat. This study is registered, number ISRCTN34455240.

FINDINGS

1422 women were assigned to receive misoprostol (n=705) or placebo (n=717). The proportion of women with blood loss of 500 mL or more within 60 min was similar between the misoprostol group (100 [14%]) and the placebo group (100 [14%]; relative risk 1.02, 95% CI 0.79-1.32). In the first 60 min, an increased proportion of women on misoprostol versus placebo, had shivering (455/704 [65%] vs 230/717 [32%]; 2.01, 1.79-2.27) and body temperature of 38 degrees C or higher (303/704 [43%] vs 107/717 [15%]; 2.88, 2.37-2.50).

INTERPRETATION

Findings from this study do not support clinical use of 600 microg sublingual misoprostol in addition to standard injectable uterotonics for treatment of post-partum haemorrhage.

FUNDING

Bill & Melinda Gates Foundation, and UNDP/UNFPA/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction.

Titrated oral compared with vaginal misoprostol for labor induction: a randomized controlled trial

OBJECTIVE

To compare the efficacy and safety of titrated oral misoprostol and vaginal misoprostol for labor induction.

METHODS

Women between 34 and 42 weeks of gestation with an unfavorable cervix (Bishop score less than or equal to 6) and an indication for labor induction were randomLy assigned to receive titrated oral or vaginal misoprostol. The titrated oral misoprostol group received a basal unit of 20 mL misoprostol solution (1 mcg/mL) every 1 hour for four doses and then were titrated against individual uterine response. The vaginal group received 25 mcg every 4 hours until attaining a more favorable cervix. Vaginal delivery within 12 hours was the primary outcome. The data were analyzed by intention-to-treat.

RESULTS

Titrated oral misoprostol was given to 101 (48.8%) women and vaginal misoprostol to 106 (51.2%) women. Completed vaginal delivery occurred within 12 hours in 75 (74.3%) women in the titrated oral group and 27 (25.5%) women in the vaginal group (relative risk [RR] 8.44, 95% confidence interval [CI] 4.52-15.76). The incidence of hyperstimulation was 0.0% in the titrated oral group compared with 11.3% in the vaginal group (RR 0.08, 95% CI 0.01-0.61). Although more women experienced nausea (10.9%) in the titrated oral group (RR 27.07, 95% CI 1.57-465.70), fewer infants had Apgar scores of less than 7 at 1 minute in the titrated oral group than in the vaginal group (RR 0.10, 95% CI 0.01-0.76).

CONCLUSION

Titrated oral misoprostol is associated with a lower incidence of uterine hyperstimulation and a lower cesarean delivery rate than vaginal misoprostol for labor induction in patients with unfavorable cervix.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00529295

LEVEL OF EVIDENCE

I.

[Misoprostol for treating postpartum hemorrhages]

Postpartum hemorrhage is defined by bleeding > 500 mL through the vagina. It is one of the obstetrical complications that obstetricians fear most. It is the leading cause of maternal mortality in the world, especially in developing countries. The reference treatments in France are parenteral oxytocin and sulprostone. Sulprostone involves sometimes fatal side effects, and must be administered only in appropriate health care facilities. It also has the major disadvantage of requiring refrigeration. Misoprostol has uterotonic properties that have led to its occasional off-label use in the treatment of postpartum hemorrhage, by rectal or sublingual administration, as an alternative to sulprostone. A careful review of the literature on this particular use of misoprostol is essential.

Misoprostol versus oxytocin for the reduction of postpartum blood loss

OBJECTIVE

To compare the effect of 400 mug of oral misoprostol with 5 U of intravenous oxytocin in the reduction of postpartum blood loss and prevention of postpartum hemorrhage.

METHODS

In a prospective, double-blind, randomized controlled trial conducted in a tertiary maternity hospital 622 women received either 400 mug of oral misoprostol or 5 U of intravenous oxytocin after delivery of the anterior shoulder or within 1 min of delivery. The primary outcome was a hematocrit drop of 10% or greater 24 h postpartum. The secondary outcomes were a hemoglobin drop of 30 mg/L or greater, the use of additional oxytocin, an estimated blood loss greater than 1000 mL, manual removal of the placenta, a blood transfusion, and shivering and fever (>or=38 degrees C) as adverse effects of misoprostol.

RESULTS

There was no difference between the 2 groups regarding the primary outcome (a >or=10% hematocrit drop occurred in 3.4% and 3.7% of the participants in the oxytocin and misoprostol groups, P=0.98). The rate of use of additional oxytocin was higher in the misoprostol group (51% versus 40.5%, P=0.01). Shivering was confined to the misoprostol group (6.8%), and fever occurred in 12.5% of the women in the misoprostol group and 0.3% of the women in the oxytocin group.

CONCLUSION

The routine use of 400 microg of oral misoprostol was no less effective than 5 U of intravenous oxytocin in reducing blood loss after delivery, as assessed by change in postpartum hematocrit. The adverse effects of misoprostol were mild and self-limiting.

Pilot study of labor induction with titrated oral misoprostol

OBJECTIVE

To evaluate the safety and efficacy of titrated oral misoprostol for labor induction at term.

MATERIALS AND METHODS

Seventy-seven pregnant women (37 nullipara and 40 multipara), with medical or obstetric indications for labor induction after 37 weeks of gestation and unfavorable cervices (Bishop's score < 7), were induced according to the principles of titrated oral doses of misoprostol against uterine response. Our primary outcome measurements were the percentage of patients who had a vaginal delivery within 24 hours of induction and the interval from induction to vaginal delivery. Secondary measurements included oxytocin requirement, total misoprostol dosage, number of cesarean deliveries, induction failure, uterine hyperstimulation rates and neonatal outcomes.

RESULTS

Seventy-five women (97.4%) experienced active labor within 24 hours, with 72 (93.5%) completing vaginal delivery within 24 hours. The mean interval from induction to vaginal delivery for all the women was 9.7 hours, with a 2.3-hour active phase. The mean misoprostol dosage was 206 microg, with eight women (10.4%) requiring oxytocin augmentation. There was no uterine hyperstimulation or induction failure, except for seven cases of uterine tachysystole (9.1%).

CONCLUSION

Titrated oral misoprostol is a safe and effective method of labor induction because the dosage can be adjusted according to individual response.

Misoprostol Administered by Epithelial Routes

OBJECTIVE

To quantify and compare serum levels and uterine effects following vaginal (dry), vaginal (moistened), buccal, and rectal misoprostol administration.

METHODS

Forty women seeking elective abortion between 6 and 12 6/7 weeks were randomly assigned to receive 400 mug of misoprostol by one of four routes. A 2.5-mm pressure monitoring catheter was placed through the cervix to the uterine fundus to record uterine tone and activity during the 5-hour observation period. Serum levels of misoprostol acid were measured at 15 and 30 minutes, then every 30 minutes.

RESULTS

The four groups were similar in age, race or ethnicity, body mass index, parity, and gestation. Serum levels after vaginal, vaginal moistened and buccal administration rose gradually, peaked between 15 and 120 minutes and fell slowly. Vaginal and vaginal moistened routes produced higher peak serum levels than buccal and rectal (445.9 and 427.1 compared with 264.8 and 202.2 pg/mL; P = .03) and higher serum concentration area under the curve at 5 hours (1,025.0 and 1279.4 compared with 519.6 and 312.5 pg-hr/mL; P < .001). Uterine tone and activity, however, were similar for buccal and the two vaginal routes. After rectal administration, serum levels peaked earlier (P < .001) then dropped more abruptly, and peak uterine tone (P < .001) and total activity (P = .04) were lower than after the other routes.

CONCLUSION

Although serum levels were lower for buccal compared with the vaginal routes, the three routes produced similar uterine tone and activity. Rectal administration produced lower uterine tone and activity. Vaginal serum levels were two to three and a half times higher than those observed in prior misoprostol pharmacokinetic studies.

Oral misoprostol vs. intravenous oxytocin in reducing blood loss after emergency cesarean delivery

OBJECTIVE

To compare the effectiveness of oral misoprostol and intravenous oxytocin in reducing blood loss in women undergoing indicated or elective cesarean delivery (CD) under spinal anesthesia.

METHODS

In this prospective, double-blind pilot study, 56 parturients who received 5 IU of intravenous oxytocin after cord clamping were randomized to further receive either misoprostol orally and a placebo infusion intravenously or placebo orally and an oxytocin infusion intravenously.

RESULTS

After adjustment was made for the sonographically estimated amniotic fluid volume, there was no statistical difference in blood loss between the 2 groups (mean+/-S.D., 1083+/-920 mL in the oxytocin group vs. 970+/-560 mL in the misoprostol group; P=.59).

CONCLUSION

Oxytocin followed by oral misoprostol is as effective as an oxytocin injection followed by an oxytocin infusion in reducing postoperative blood loss after CD, and the protocol may be a safe, valuable, and cost-effective alternative to oxytocin alone. Visual estimation of intraoperative blood loss undervalues the effective value of misoprostol use by 30%.

Placebo-controlled randomized comparison of vaginal with rectal misoprostol in the prevention of postpartum hemorrhage

AIM

To compare vaginally administered misoprostol to rectally administered misoprostol and placebo in a prospective randomized placebo-controlled study.

METHODS

One hundred and fifty women with singleton vaginal deliveries were randomized (50 women in each arm) to receive 400-microg misoprostol tablets (crushed and suspended in a microenema) intravaginally, or 400-microg misoprostol tablets rectally, or two placebo lactose tablets rectally. The medication was administered immediately after delivery of the placenta. Women with profuse hemorrhage and delayed placental separation (>30 min) were excluded. Our outcome measures were postpartum blood loss 1 h after administration, and change in hemoglobin and hematocrit values from baseline to postpartum day 1. Analysis of variance and chi-squared tests were used to compare the outcome variables between groups.

RESULTS

One hundred and twenty-six women were available for analysis. Baseline characteristics were similar across the groups. The number of excluded subjects, the estimated blood loss, and the drop in hemoglobin and hematocrit values did not differ between the three groups (P > 0.05).

CONCLUSIONS

Misoprostol administered vaginally or rectally at a dosage of 400 microg following placental separation was not effective for decreasing postpartum bleeding in women without excessive hemorrhage.