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Comparison of rates of adverse events in adolescent and adult women undergoing medical abortion: population register based study

BMJ 2011; 342 doi: (Published 20 April 2011) Cite this as: BMJ 2011;342:d2111
  1. Maarit Niinimäki, consultant gynaecologist1,
  2. Satu Suhonen, chief physician2,
  3. Maarit Mentula, consultant gynaecologist3,
  4. Elina Hemminki, research professor4,
  5. Oskari Heikinheimo, chief physician3,
  6. Mika Gissler, research professor45
  1. 1Department of Obstetrics and Gynecology, University Hospital of Oulu, Finland
  2. 2City of Helsinki Health Centre, Unit for Maternal and Child Health Care and Health Promotion, Helsinki, Finland
  3. 3Department of Obstetrics and Gynaecology/Kätilöopisto Hospital, Helsinki University Central Hospital, PO Box 610, 00029 HUS, Helsinki, Finland
  4. 4National Institute for Health and Welfare, Helsinki, Finland
  5. 5Nordic School of Public Health, Gothenburg, Sweden
  1. Correspondence to: O Heikinheimo oskari.heikinheimo{at}
  • Accepted 20 February 2011


Objective To determine the risks of short term adverse events in adolescent and older women undergoing medical abortion.

Design Population based retrospective cohort study.

Setting Finnish abortion register 2000-6.

Participants All women (n=27 030) undergoing medical abortion during 2000-6, with only the first induced abortion analysed for each woman.

Main outcome measures 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 and genital Chlamydia trachomatis infections detected concomitantly with abortion and linked with data from the abortion register for 2004-6.

Results During 2000-6, 3024 adolescents and 24 006 adults underwent at least one medical abortion. The rate of chlamydia infections was higher in the adolescent cohort (5.7% v 3.7%, P<0.001). The incidence of adverse events among adolescents was similar or lower than that among the adults. The risks of haemorrhage (adjusted odds ratio 0.87, 95% confidence interval 0.77 to 0.99), incomplete abortion (0.69, 0.59 to 0.82), and surgical evacuation (0.78, 0.67 to 0.90) were lower in the adolescent cohort. In subgroup analysis of primigravid women, the risks of incomplete abortion (0.68, 0.56 to 0.81) and surgical evacuation (0.75, 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 surgical evacuation.

Conclusions The incidence of adverse events after medical abortion was similar or lower among adolescents than among older women. Thus, medical abortion seems to be at least as safe in adolescents as it is in adults.


  • The preliminary results of this study were presented at the International Federation of Obstetrics and Gynecology (FIGO) meeting in Cape Town, South Africa October 2009, and in the International Federation of Professional Abortion and Contraception Associates (FIAPAC) meeting in Seville Spain, October 2010 (MN). We thank Aini Bloigu (National institute for Health and Welfare, Oulu, Finland) for her professional help with the statistics.

  • Contributors: All authors participated in the design of the study. MN carried out the data analysis, wrote the first draft of the manuscript, and is a guarantor of the study. All authors contributed to the subsequent writing of the paper and gave substantial input into the study. OH obtained funding for the study. MG is in charge of the Finnish reproductive registries (including the abortion register).

  • Funding: This study was funded by Finnish Cultural Foundation (MN), Helsinki University Central Hospital Research Funds (OH, MN), and University Hospital of Oulu Research Funds (MN).

  • Competing interests: All authors have completed the Unified Competing Interest form at (available on request from the corresponding author) and declare: OH has lectured at an educational event organised by Nordic Drugs and has been principal investigator in clinical studies sponsored by the Concept Foundation; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: This study was approved by the ethics committee of the Northern Ostrobothnia Hospital District in October 2005 (No 46/2005). The Ministry of Social Affairs and Health, and Statistics Finland gave permission for the use of confidential personal level data from the registries. The data protection ombudsman was notified about the data linkage before the analyses, as required by national data protection legislation.

  • Data sharing: No additional data available.

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