Forensic Toxicological Aspects of Misoprostol Use in Pharmacological Abortions

The aim of this study was establishment of an UHPLC-QqQ-MS/MS method for the deter-mination of misoprostol acid in biological specimens in cases of pharmacological abortions. Forensic toxicological examination was performed in three different biological samples (whole blood, placenta and fetal liver). The validation parameters of the method were as follows: limit of detection: 25 pg/mL; limit of quantification: 50 pg/mL, coefficient of determination: >0.999 (R2), intra- and interday accuracy and precision: not greater than 13.7%. The recovery and matrix effect were in the range of 88.3−95.1% and from −11.7 to −4.9%, respectively. Toxicological analysis of the mother’s blood (collected two days after pregnancy termination) did not reveal any abortifacients; however, misoprostol acid was found in the placenta (793 pg/g) and fetal liver (309 pg/g). The second case involved a fetus found near a garbage container. The concentration of misoprostol acid in the placenta was 2332 pg/g. In the presented study, an extensive literature review of misoprostol pharmacokinetics studies was performed. To our knowledge, the UHPLC-QqQ-MS/MS technique presented in this paper is the first quantitative method applied for forensic toxicological purposes. In addition, postmortem concentrations of misoprostol acid in miscarried fetuses due to illegal abortions were reported for the first time.

The impact of vaginal pH on induction of labour outcomes: a meta-analysis of observational studies

The present meta-analysis evaluates the impact of an acidic vaginal pH on the progress of labour induction with dinoprostone and misoprostol. We searched Medline, Scopus, EMBASE, Cochrane Central Register of Controlled Trials CENTRAL, Clinicaltrials.gov and Google Scholar databases for relevant studies. Meta-analysis was performed with Rstudio using the meta function and trial sequential analysis was used to evaluate the adequacy of sample size. Nine studies were retrieved that involved 809 patients. An acidic vaginal pH did not influence the efficacy of misoprostol or dinoprostone in terms of accomplishing a successful vaginal delivery (OR 0.62, 95% CI 0.29, 1.30). The interval to delivery was unaffected by the acidity of vaginal pH (Mean Difference 4.18 h, 95% CI -2.09, 10.45). In conclusion, vaginal pH does not seem to affect the potency of vaginally administered prostaglandins; therefore, moistening of vaginal tables with acetic acid does not seem reasonable until further evidence becomes available.

Medical methods for first trimester abortion

BACKGROUND

Medical abortion became an alternative method of pregnancy termination following the development of prostaglandins and antiprogesterone in the 1970s and 1980s. Recently, synthesis inhibitors of oestrogen (such as letrozole) have also been used to enhance efficacy. The most widely researched drugs are prostaglandins (such as misoprostol, which has a strong uterotonic effect), mifepristone, mifepristone with prostaglandins, and letrozole with prostaglandins. More evidence is needed to identify the best dosage, regimen, and route of administration to optimise patient outcomes. This is an update of a review last published in 2011.

OBJECTIVES

To compare the effectiveness and side effects of different medical methods for first trimester abortion.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, Global Health, and LILACs on 28 February 2021. We also searched Clinicaltrials.gov and the World Health Organization's (WHO) International Clinical Trials Registry Platform, and reference lists of retrieved papers.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) that compared different medical methods for abortion before the 12th week of gestation. The primary outcome is failure to achieve complete abortion. Secondary outcomes are mortality, surgical evacuation, ongoing pregnancy at follow-up, time until passing of conceptus, blood transfusion, side effects and women's dissatisfaction with the method.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected and evaluated studies for inclusion, and assessed the risk of bias. We processed data using Review Manager 5 software. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

We included 99 studies in the review (58 from the original review and 41 new studies). 1. Combined regimen mifepristone/prostaglandin Mifepristone dose: high-dose (600 mg) compared to low-dose (200 mg) mifepristone probably has similar effectiveness in achieving complete abortion (RR 1.07, 95% CI 0.87 to 1.33; I2 = 0%; 4 RCTs, 3494 women; moderate-certainty evidence). Prostaglandin dose: 800 µg misoprostol probably reduces abortion failure compared to 400 µg (RR 0.63, 95% CI 0.51 to 0.78; I2= 0%; 3 RCTs, 4424 women; moderate-certainty evidence). Prostaglandin timing: misoprostol administered on day one probably achieves more success on complete abortion than on day three (RR 1.94, 95% CI 1.05 to 3.58; 1489 women; 1 RCT; moderate-certainty evidence). Administration strategy: there may be no difference in failure of complete abortion with self-administration at home compared with hospital administration (RR 1.63, 95% CI 0.68 to 3.94; I2 = 84%; 2263 women; 4 RCTs; low-certainty evidence), but failure may be higher when administered by nurses in hospital compared to by doctors in hospital (RR 2.69, 95% CI 1.39 to 5.22; I2 = 66%; 3 RCTs, 3056 women; low-certainty evidence). Administration route: oral misoprostol probably leads to more failures than the vaginal route (RR 2.38, 95% CI 1.46 to 3.87; I2 = 39%; 3 RCTs, 1704 women; moderate-certainty evidence) and may be associated with more frequent side effects such as nausea (RR 1.14, 95% CI 1.03 to 1.26; I2 = 0%; 2 RCTs, 1380 women; low-certainty evidence) and diarrhoea (RR 1.80 95% CI 1.49 to 2.17; I2 = 0%; 2 RCTs, 1379 women). Compared with the vaginal route, complete abortion failure is probably lower with sublingual (RR 0.68, 95% CI 0.22 to 2.11; I2 = 59%; 2 RCTs, 3229 women; moderate-certainty evidence) and may be lower with buccal administration (RR 0.71, 95% CI 0.34 to 1.46; I2 = 0%; 2 RCTs, 479 women; low-certainty evidence), but sublingual or buccal routes may lead to more side effects. Women may experience more vomiting with sublingual compared to buccal administration (RR 1.33, 95% CI 1.01 to 1.77; low-certainty evidence). 2. Mifepristone alone versus combined regimen The efficacy of mifepristone alone in achieving complete abortion compared to combined mifepristone/prostaglandin up to 12 weeks is unclear (RR of failure 3.25, 95% CI 0.81 to 13.09; I2 = 83%; 3 RCTs, 273 women; very low-certainty evidence). 3. Prostaglandin alone versus combined regimen Nineteen studies compared prostaglandin alone to a combined regimen (prostaglandin combined with mifepristone, letrozole, estradiol valerate, tamoxifen, or methotrexate). Compared to any of the combination regimens, misoprostol alone may increase the risk for failure to achieve complete abortion (RR of failure 2.39, 95% CI 1.89 to 3.02; I2 = 64%; 18 RCTs, 3471 women; low-certainty evidence), and with more diarrhoea. 4. Prostaglandin alone (route of administration) Oral misoprostol alone may lead to more failures in complete abortion than the vaginal route (RR 3.68, 95% CI 1.56 to 8.71, 2 RCTs, 216 women; low-certainty evidence). Failure to achieve complete abortion may be slightly reduced with sublingual compared with vaginal (RR 0.69, 95% CI 0.37 to 1.28; I2 = 87%; 5 RCTs, 2705 women; low-certainty evidence) and oral administration (RR 0.58, 95% CI 0.11 to 2.99; I2 = 66%; 2 RCTs, 173 women). Failure to achieve complete abortion may be similar or slightly higher with sublingual administration compared to buccal administration (RR 1.11, 95% CI 0.71 to 1.74; 1 study, 401 women).

AUTHORS' CONCLUSIONS

Safe and effective medical abortion methods are available. Combined regimens (prostaglandin combined with mifepristone, letrozole, estradiol valerate, tamoxifen, or methotrexate) may be more effective than single agents (prostaglandin alone or mifepristone alone). In the combined regimen, the dose of mifepristone can probably be lowered to 200 mg without significantly decreasing effectiveness. Vaginal misoprostol is probably more effective than oral administration, and may have fewer side effects than sublingual or buccal. Some results are limited by the small numbers of participants on which they are based. Almost all studies were conducted in settings with good access to emergency services, which may limit the generalisability of these results.

Pharmacokinetics of Vaginal vs Buccal Misoprostol for Labor Induction at Term

The IMPROVE study (NCT02408315) compared the efficacy and safety of vaginal and buccal administration of misoprostol for full‐term, uncomplicated labor induction. This report compares the pharmacokinetics of misoprostol between vaginal and buccal routes. Women greater than or equal to 14 years of age undergoing induction of labor greater than or equal to 37 weeks gestation without significant complications were randomized to vaginal or buccal misoprostol 25 μg followed by 50 μg doses every 4 h. Misoprostol acid concentrations were determined using liquid chromatography‐tandem mass spectrometry for the first 8 h in a subgroup of participants. A population pharmacokinetic model was developed using NONMEM. Plasma concentrations (n = 469) from 47 women were fit to a one‐compartment nonlinear clearance model. The absorption rate constant (k_a) was dependent on both route and dose of administration: buccal 25 μg 0.724 (95% confidence interval, 0.54–0.92) h⁻¹; 50 μg 0.531 (0.37–0.63) h⁻¹; vaginal 25 μg 0.507 (0. 2–1. 4) h⁻¹; and 50 μg 0.246 (0.103–0.453) h⁻¹. Relative bioavailability for vaginal compared to buccal route was 2.4 (1.63–4.77). There was no effect of body mass index or age on apparent clearance 705 (431–1099) L/h or apparent volume of distribution 632 (343–1008) L. The area under the concentration–time curve to 4 h following the first 25 μg dose of misoprostol was 16.5 (15.4–17.5) pg h/ml for buccal and 34.3 (32.5–36.1) pg h/ml for vaginal administration. The rate of buccal absorption was two times faster than that of vaginal, whereas bioavailability of vaginal administration was 2.4 times higher than that of buccal. Decreased time to delivery observed with vaginal dosing may be due to higher exposure to misoprostol acid compared to buccal.

Determination of misoprostol acid in plasma samples by UPLC-MS/MS with application in a maternal-fetal pharmacokinetic study following a low misoprostol dose vaginally to induce labor

Misoprostol is a prostaglandin E1 synthetic analogous used for elective interruptions of early pregnancy, treatment of incomplete abortion, postpartum hemorrhage and induction of full-term labor. Its a lipophilic drug, passing by extensive and rapid pre-systemic metabolism into the active metabolite, misoprostol acid (MA). The objective of this study was to develop and validate a highly sensitive method for MA determination in plasma using UPLC-MSMS, with application in a study of maternal-fetal pharmacokinetics in healthy parturients women (n = 10) after administration of 25 μg misoprostol vaginally. The method presented linearity of 2-10 pg/mL and acceptable precision, accuracy, plasma and solution stability. The parturients women presented median (interquartile range) values of AUC^0-6 of 68.0 (40.8-84.7) pg.h/mL, C_max of 21.9 (11.9-30.1) pg/mL and T_max of 2.25 (0.69-5.00) h. The placental transfer of MA was assessed from the umbilical vein/maternal blood ratios of 1.40 (0.91-2.13) and intervillous space/maternal blood ratios of 0.49 (0.15-3.41). In conclusion, this method presented high sensitivity, being able to quantify MA in plasma samples following a low 25 μg misoprostol administered vaginally aimed to induce labor in parturients women. Additionally, this is the first description of the placental transfer of MA after a vaginal administration of misoprostol.

Efficacy of Misoprostol Alone for First-Trimester Medical Abortion: A Systematic Review

OBJECTIVE

To summarize available data on the effectiveness and safety of single-agent misoprostol for medical abortion in the first trimester.

DATA SOURCES

We searched MEDLINE, CABI, Cochrane, EMBASE, LILACS, the Web of Science, and ClinicalTrials.gov for English-language studies that evaluated misoprostol alone for abortion of a viable pregnancy in the first trimester.

METHODS OF STUDY SELECTION

Our search yielded 1,562 citations, of which 38 included data from 53 trial groups that met our inclusion and exclusion criteria.

TABULATION, INTEGRATION, AND RESULTS

We abstracted data about each trial group, including study characteristics, treatment regimen, clinical protocol, number of women treated and followed, and numbers with outcomes of interest. We used meta-analytic methods and logistic regression to examine factors associated with surgical intervention after treatment. Among all 12,829 evaluable women, 2,536 (meta-analytic estimate 22.0%, 95% CI 18.8-25.5%) had surgical uterine evacuation. Multiple factors were significantly associated with this proportion, including misoprostol amount per dose and route of administration, loss to follow-up rate, publication date, geographic region, number of misoprostol doses, duration of dosing, and time between dosing and evaluation. Of 6,359 evaluable women, 384 (meta-analytic estimate 6.8%, 95% CI 5.3-8.5%) had ongoing pregnancies. At most 26 of 12,184 evaluable women (meta-analytic estimate 0.7%, 95% CI 0.4-1.0%) were transfused or hospitalized for abortion-related reasons. In trials that provided satisfaction data, most women were satisfied or very satisfied with the treatment (meta-analytic estimate 78%, 95% CI 71-85%).

CONCLUSIONS

Misoprostol alone is effective and safe and is a reasonable option for women seeking abortion in the first trimester. Research is indicated to further refine the regimen and to establish efficacy in the late first trimester.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO, CRD42018083589.

Moistening the new vaginal misoprostol tablets: does it increase the efficacy of cervical priming before manual vacuum aspiration in first-trimester miscarriage? A randomised clinical trial

OBJECTIVES

The primary objective of our study was to ascertain whether moistening the Brazilian formulation of vaginal misoprostol tablets increases cervical dilation before manual vacuum aspiration (MVA), compared with use of dry misoprostol, in first-trimester miscarriage. The secondary objective was to ascertain whether there was any correlation between vaginal pH and the degree of cervical dilation using a moistened or dry misoprostol tablet.

METHODS

In a single-centre, double-blind, randomised trial, 46 patients with first-trimester miscarriage were randomly allocated to treatment with dry or moistened (with 200 µl distilled water) 2 × 200 μg misoprostol tablets.

RESULTS

The median (range) cervical dilation in the wet and dry groups was 8 mm (6-12 mm) and 7 mm (5-10 mm), respectively (p = .06). The median time between misoprostol insertion and carrying out the procedure did not differ between the dry (406 min, range 180-550 min) and wet (448 min, range 180-526 min) groups (p = .1). No correlation was found between vaginal pH and cervical dilation using continuous data (p = .57; r= 0.08; 95% confidence interval -0.02, 0.3) or dichotomous data (pH ≤5/>5; cervical dilation ≥8 mm or <8 mm; p = .8).

CONCLUSION

No difference was observed in cervical dilation between moistened and non-moistened misoprostol use prior to MVA.

[Pharmacology of misoprostol (pharmacokinetic data, adverse effects and teratogenic effects)]

Misoprostol is a synthetic analogue of prostaglandin E1. It is used in gynaecology because of its properties of myometrium smooth muscle cells contraction and its effects on the cervix. Misoprostol oral bioavailability is low and several authors have assessed whether the administration by other routes increased its pharmacodynamic effects. This paper summarizes the pharmacokinetic studies after other routes of administration: vaginal, sublingual, buccal or rectal. It also provides an update on its adverse effects and teratogenic effects.