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Prognosis
30 Evidence-Based Medicine February 2012 | volume 17 | number 1 |
10.1136/ebm.2011.100064
Family Practice, The University
of British Columbia (UBC),
Vancouver, British Columbia,
Canada
Correspondence to:
Ellen R Wiebe
Family Practice, The University of
British Columbia (UBC),
1013-750 West Broadway,
Vancouver, BC V5Z-1H9,
Canada;
ellenwiebe@gmail.com
Cohort study
Adolescent girls undergoing medical abortion have lower
risk of haemorrhage, incomplete evacuation or surgical
evacuation than women above 18 years old
Ellen R Wiebe
Context
Medical abortions induced with mifepristone and
misoprostol are common, and yet there have been only
a few small studies in patients below 18 years. This study
was done to determine the short-term adverse effects of
medical abortion in younger and older women.
Methods
This was a population-based retrospective cohort
study using the Finnish abortion register from 2000
to 2006. The only exclusions were abortions over 20
weeks, and only the rst-induced abortion was anal-
ysed for each woman. The main outcome measures
were the incidence of adverse events (haemorrhage,
infection, incomplete abortion, surgical evacuation,
psychiatric morbidity, injury, thromboembolic disease
and death) among adolescent (<18 years) and older
(≥18 years) women through record linkage of Finnish
registries. The data from the abortion were linked
to data from inpatient and outpatient visits for
42 days postprocedure. Diagnoses of adverse events
were based on the 1985 report by the Royal College of
General Practicioners/Royal College of Obstetritions
and Gynaecologists (RCGP/RCOG).1
Findings
Data from 3024 adolescents and 24 006 adults were
analysed. The rate of chlamydia infections was higher in
the adolescent cohort (5.7% vs 3.7%, p<0.001). The rates
of adverse events for adolescents and adults, respec-
tively, were 12.8% and 15.4% (haemorrhage), 2% and 2%
(infection), 7% and 10.2% (incomplete abortion), 11%
and 13% (surgical evacuation) and 0.1% and 0% (psy-
chiatric morbidity). There were two deaths in the adult
group. The risks of haemorrhage (adjusted OR (AOR)
0.87, 95% CI 0.77 to 0.99), incomplete abortion (AOR
0.69, 95% CI 0.59 to 0.82) and surgical evacuation (AOR
0.78, 95% CI 0.67 to 0.90) were lower in the adolescent
cohort. In subgroup analyses of primigravid women, the
risks of incomplete abortion (AOR 0.68, 95% CI 0.56 to
0.81) and surgical evacuation (AOR 0.75, 95% CI 0.64
to 0.88) were lower in the adolescent cohort. In logistic
regression, duration of gestation was the most important
risk factor for infection, incomplete abortion and surgi-
cal evacuation.
Commentary on: Niinimäki M, Suhonen S, Mentula M, et al. Comparison of rates of adverse events
in adolescent and adult women undergoing medical abortion: population register based study. BMJ
2011;342:d2111.
Commentary
This study credibly answers the research question and
reassures us that medical abortions are as safe for
adolescents as they are for adults. The subgroup analy-
sis of the primigravid women is the most important, as
we know that primigravid patients have fewer incom-
plete abortions.2 These nding are consistent with the
ndings from previous studies with smaller numbers of
adolescents.3 4
We are indebted to the researchers of countries like
Finland who have access to national registers that can
yield such rich data. In North America and many other
countries, it would not be possible to do this study, where
population-based data are much more limited, and sam-
ples may not be representative of populations and may
miss complications because of lack of follow-up when
doing clinical trials.
The main problem with extrapolating from the
results of this study to other settings comes from under-
standing the demographics of the patients, the medi-
cal protocols used and the de nitions of adverse events
in Finland. North America is much more ethnically
diverse than Finland. In addition, different protocols
are used elsewhere; a survey of the National Abortion
Federation,5 whose members provide about half of all
abortions in the USA and Canada, indicated that most
medical abortions were performed with 200 mg of
mifepristone followed 1–2 days later by home admin-
istration of 800 μg misoprostol vaginally in 2001. In
Finland, the protocol was mifepristone 600 mg followed
by clinic-administered 200 μg misoprostol orally. Most
importantly, the de nitions of adverse events can dif-
fer. For example, in this study, infection was de ned
as a hospital/clinic visit with a diagnosis of infection
compared with the Planned Parenthood de nition of
“fever accompanied by pelvic pain and was treated with
intravenous antibiotics either in an emergency depart-
ment or inpatient unit.”3
As these very important population-based studies
coming from countries with excellent registries cannot be
replicated in countries without such registries, we need to
have a more complete understanding of the implications
of differing demographics, protocols and de nitions of
adverse events in order to apply the results of registry
studies such as this one widely.
Competing interests None.
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Prognosis
31
Evidence-Based Medicine February 2012 | volume 17 | number 1 |
References
1. Induced abortion operations and their early sequelae. Joint study
of the Royal College of General Practitioners and the Royal
College of Obstetricians and Gynaecologists. J R Coll Gen Pract
1985;35:175–80.
2. Bartley J, Tong S, Everington D, et al. Parity is a major
determinant of success rate in medical abortion: a retrospective
analysis of 3161 consecutive cases of early medical abortion
treated with reduced doses of mifepristone and vaginal
gemeprost. Contraception 2000;62:297–303.
3. Fjerstad M, Trussell J, Sivin I, et al. Rates of serious infection
after changes in regimens for medical abortion. N Engl J Med
2009;361:145–51.
4. Ngo TD, Park MH, Shakur H, et al. Comparative effectiveness,
safety and acceptability of medical abortion at home and
in a clinic: a systematic review. Bull World Health Organ
2011;89:360–70.
5. Wiegerinck MM, Jones HE, O’Connell K, et al. Medical abortion
practices: a survey of National Abortion Federation members in
the United States. Contraception 2008;78:486–91.
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