1st trimester induced abortion
(also known as termination of pregnancy)
The full guidance on 1st trimester induced abortion has been published in the International Journal of Gynecology and Obstetrics 2007;99(supp 2):S172-7, and is available as a read-only pfd file here.
Alternative guidelines on 1st trimester induced abortion are available here.
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Recommended Dosage: 800 mcg vaginally 12-hourly x3 |
REGIMEN
Dose/ Route of administration
The first choice should be 800 mcg administered by the vaginal route every 6, 12 or 24 hours for a maximum of three doses. Three doses of 800 mcg at 3-hourly intervals can also be used sublingually. Moistening the tablets appears to slightly increase plasma levels, but no improvement in the clinical effects has been demonstrated. Doses higher than 800 mcg are not recommended due to increased side effects.
Course of Treatment
Several studies carried out in developed and developing countries have shown that home administration of misoprostol is effective and safe up to 9 weeks LMP. Most of those studies have been done using the combination of mifepristone and misoprostol and only a few with misoprostol alone.
Prerequisites:
1. Voluntary termination of the pregnancy and informed consent of the woman about her choices and the nature of the procedure.
2. Backup arrangements for surgical abortion.
3. Dating gestational age and ruling out ectopic pregnancy according to local standards.
4. If required by national guidelines, blood group and Rhesus factor should be determined and in cases where women are Rhesus negative, a dose of anti-D serum should be administered prior to treatment. However, there is currently little evidence to support that Rhesus factor iso-immunization occurs for pregnancies up to 63 days gestation.
5. Where resources are available, and depending on the clinical situation, hemoglobin, haematocrit and screening for STDs may also be provided depending on local prevalence and guidelines. In addition, serological tests to diagnose for syphilis, HIV and hepatitis B and C surface antigen may also be used.
EFFECTIVENESS
Despite the wide range of results from different studies and different regimens, the success rate, defined as the complete abortion is around 90% during the first trimester of pregnancy. Success depends on the length of the time interval between treatment and the assessment of the outcome.
Depending on the regimen used, pregnancy continues in 4 to 8 % of women with gestational age of up to 63 days when vaginal misoprostol is used alone)
Time to achieve effect
In the majority of cases, expulsion of the product of conception occurs hours after administration: close to 70% within the first 12 hours, around 80% during the first 24 hours, 95% within 48 hours and further increases until at least 72 hours after the initial dose. However there may be a large variability depending on route, dose and time interval between misoprostol doses.
These recommendations are produced by an expert group on misoprostol brought together by WHO in Bellagio, Italy in Feb 2007. These recommendations do not reflect official WHO guidelines, but have been released early so as to provide guidance to clinicians worldwide. The excerpt above is taken from: