Reproductive outcomes following induced abortion: a national register-based cohort study in Scotland
- Siladitya Bhattacharya1,
- Alison Lowit1,
- Sohinee Bhattacharya1,
- Edwin Amalraj Raja1,
- Amanda Jane Lee1,
- Tahir Mahmood2,
- Allan Templeton1
- 1Division of Applied Health Sciences, University of Aberdeen, Aberdeen, UK
- 2Department of Obstetrics and Gynaecology, Victoria Hospital, Kirkcaldy, UK
- Correspondence to Dr Sohinee Bhattacharya;
- Received 20 January 2012
- Accepted 27 June 2012
- Published 6 August 2012
Objective To investigate reproductive outcomes in women following induced abortion (IA).
Design Retrospective cohort study.
Setting Hospital admissions between 1981 and 2007 in Scotland.
Participants Data were extracted on all women who had an IA, a miscarriage or a live birth from the Scottish Morbidity Records. A total of 120 033, 457 477 and 47 355 women with a documented second pregnancy following an IA, live birth and miscarriage, respectively, were identified.
Outcomes Obstetric and perinatal outcomes, especially preterm delivery in a second ongoing pregnancy following an IA, were compared with those in primigravidae, as well as those who had a miscarriage or live birth in their first pregnancy. Outcomes after surgical and medical termination as well as after one or more consecutive IAs were compared.
Results IA in a first pregnancy increased the risk of spontaneous preterm birth compared with that in primigravidae (adjusted RR (adj. RR) 1.37, 95% CI 1.32 to 1.42) or women with an initial live birth (adj. RR 1.66, 95% CI 1.58 to 1.74) but not in comparison with women with a previous miscarriage (adj. RR 0.85, 95% CI 0.79 to 0.91). Surgical abortion increased the risk of spontaneous preterm birth compared with medical abortion (adj. RR 1.25, 95% CI 1.07 to 1.45). The adjusted RRs (95% CI) for spontaneous preterm delivery following two, three and four consecutive IAs were 0.94 (0.81 to 1.10), 1.06 (0.76 to 1.47) and 0.92 (0.53 to 1.61), respectively.
Conclusions The risk of preterm birth after IA is lower than that after miscarriage but higher than that in a first pregnancy or after a previous live birth. This risk is not increased further in women who undergo two or more consecutive IAs. Surgical abortion appears to be associated with an increased risk of spontaneous preterm birth in comparison with medical termination of pregnancy. Medical termination was not associated with an increased risk of preterm delivery compared to primigravidae.
To cite: Bhattacharya S, Lowit A, Bhattacharya S, et al. Reproductive outcomes following induced abortion: a national register-based cohort study in Scotland. BMJ Open 2012;2:e000911. doi:10.1136/bmjopen-2012-000911
Contributors AT conceived the idea for the study. SB was the principal investigator. He designed the study along with SohB, AT, AJL and TM, led the funding application, managed the project, interpreted the results and wrote the first draft of the paper. AL cleaned the data and performed some of the initial analyses. SohB cowrote the funding application, facilitated data manipulation, interpreted the results and helped to draft the paper. EAR performed the statistical analysis and interpreted the results with input from AJL. All authors commented on, and contributed to the final draft of the paper.
Funding The Chief Scientist Office Scotland funded the study (grant number CZG/2/403). The views expressed are those of the authors and not the funding body.
Competing interests The authors declare that they have no competing interests.
Ethics approval The ethics approval was provided by the Privacy Advisory Committee of Information and Services Division, NHS, Scotland.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement There are no unpublished data available for confidentiality reasons.
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