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Effect of interpregnancy interval on outcomes of pregnancy after miscarriage: retrospective analysis of hospital episode statistics in Scotland

BMJ 2010; 341 doi: (Published 05 August 2010) Cite this as: BMJ 2010;341:c3967
  1. Eleanor R Love, medical student1,
  2. Siladitya Bhattacharya, professor of reproductive medicine1,
  3. Norman C Smith, consultant obstetrician, NHS Grampian2,
  4. Sohinee Bhattacharya, lecturer in obstetric epidemiology3
  1. 1University of Aberdeen, Aberdeen
  2. 2Department of Obstetrics and Gynaecology, Aberdeen Maternity Hospital, Aberdeen
  3. 3Dugald Baird Centre for Research on Women’s Health, Aberdeen Maternity Hospital, Aberdeen, AB25 2ZD
  1. Correspondence to: Sohinee Bhattacharya sohinee.bhattacharya{at}
  • Accepted 24 June 2010


Objective To determine the optimum interpregnancy interval after miscarriage in a first recorded pregnancy.

Design Population based retrospective cohort study.

Setting Scottish hospitals between 1981 and 2000.

Participants 30 937 women who had a miscarriage in their first recorded pregnancy and subsequently became pregnant.

Main outcome measures The primary end point was miscarriage, live birth, termination, stillbirth, or ectopic pregnancy in the second pregnancy. Secondary outcomes were rates of caesarean section and preterm delivery, low birthweight infants, pre-eclampsia, placenta praevia, placental abruption, and induced labour in the second pregnancy.

Results Compared with women with an interpregnancy interval of 6-12 months, those who conceived again within six months were less likely to have another miscarriage (adjusted odds ratio 0.66, 95% confidence interval 0.57 to 0.77), termination (0.43, 0.33 to 0.57), or ectopic pregnancy (0.48, 0.34 to 0.69). Women with an interpregnancy interval of more than 24 months were more likely to have an ectopic second pregnancy (1.97, 1.42 to 2.72) or termination (2.40, 1.91 to 3.01). Compared with women with an interpregnancy interval of 6-12 months, women who conceived again within six months and went on to have a live birth in the second pregnancy were less likely to have a caesarean section (0.90, 0.83 to 0.98), preterm delivery (0.89, 0.81 to 0.98), or infant of low birth weight (0.84, 0.71 to 0.89) but were more likely to have an induced labour (1.08, 1.02 to 1.23).

Conclusions Women who conceive within six months of an initial miscarriage have the best reproductive outcomes and lowest complication rates in a subsequent pregnancy.


  • We thank Joanne Hatty for extraction of data from the Scottish morbidity records databases and Jill Mollison for statistical advice on the revised version of this paper.

  • Contributors: ERL analysed the data and wrote the first draft of the paper. SohB extracted data and supervised the data analysis and writing of the first draft of the paper. SB conceived the study and was responsible for overall supervision. NCS helped with the clinical interpretation of the results and commented on the first draft of the paper. All authors contributed to the writing of the final draft of the paper. SohB is the guarantor.

  • Funding: This research was partially funded by the Chief Scientist’s Office in Scotland (project No CZG_2_283). SB and SohB were employed by the University of Aberdeen at the time of doing this research and are independent from the funders. ERL is a medical student and NCS is employed by NHS Grampian. The findings and their interpretation in this study are the authors’ own, and neither the funders nor the sponsors played any part in arriving at the conclusions.

  • Competing interests: All authors have completed the unified competing interest form (available on request from the corresponding author) and declare that: ERL,SB, NCS, and SohB have support from the University of Aberdeen for the submitted work; ERL, SB, NCS, and SohB have no relationships with companies that might have an interest in the submitted work in the previous three years; and ERL, SB, NCS, and SohB have no non-financial interests that may be relevant to the submitted work.

  • Ethical approval: This research proposal was approved by the privacy advisory committee of the Information and Services Division NHS Scotland. Formal ethical approval was not considered necessary by North of Scotland Research Ethics Service, as only anonymised data were analysed in this study.

  • Data sharing: No additional data available.

  • Accepted 24 June 2010

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