Temporal trends in multiple births after in vitro fertilisation in Sweden, 1982-2001: a register study

BMJ 2005; 331 doi: https://doi.org/10.1136/bmj.38443.595046.E0 (Published 11 August 2005) Cite this as: BMJ 2005;331:382
  1. Bengt Källén, professor (embryol@embryol.lu.se)1,
  2. Orvar Finnström, professor2,
  3. Karl Gösta Nygren, associate professor3,
  4. Petra Otterblad Olausson, head of register4
  1. 1 Centre for Reproduction Epidemiology, Tornblad Institute, University of Lund, Biskopsgatan 7, S-223 62 Lund, Sweden
  2. 2 Department of Paediatrics, University Hospital, S-581 85 Linköping, Sweden
  3. 3 IVF Clinic, Sophiahemmet, S-114 86 Stockholm, Sweden
  4. 4 Centre for Epidemiology, National Board of Health and Welfare, Stockholm, Sweden
  1. Correspondence to: Bengt Källén
  • Accepted 31 March 2005


During the 20 years since the first child was born in Sweden after in vitro fertilisation, clinical policy has changed. During the early 1990s, the clinics performing in vitro fertilisation and the National Board of Health and Welfare agreed to reduce the number of embryos transferred to the uterus during in vitro fertilisation from three to two. Here, we describe the changes in multiple birth rates that have resulted from this change and their impact on the rate of preterm birth. In future papers we intend to describe maternal and child characteristics in greater detail.

Participants, methods, and results

In Sweden 17 hospitals or private clinics perform in vitro fertilisation. The National Board of Health and Welfare requested information from these laboratories on all women who had undergone in vitro fertilisation and who had had a baby or whose pregnancy outcome was not known. By linking these data with the Swedish medical birth register, we identified infants born from 1982 to …

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