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Preterm birth in Sweden 1973-2001: rate, subgroups, and effect of changing patterns in multiple births, maternal age,

Nils-Halvdan Morken1, Karin Källen, Henrik Hagberg

  • 1Department of Obstetrics and Gynecology, Telemark Hospital, Skien, Norway. nhmorken@online.no

Acta Obstetricia Et Gynecologica Scandinavica
|May 20, 2005
PubMed

Insights

Sweden

Area of Science:

  • Reproductive Health
  • Public Health Surveillance

Background:

  • Examined trends in preterm birth rates in Sweden from 1973-2001.
  • Described the proportion of spontaneous versus indicated preterm births.
  • Assessed risk factors for preterm birth subgroups.

Purpose of the Study:

  • To evaluate changes in the preterm birth rate in Sweden between 1973 and 2001.
  • To describe the proportion of spontaneous and indicated preterm births.
  • To assess risk factors for preterm birth subgroups from 1991 to 2001.

Main Methods:

  • Population-based register study using the Swedish Medical Birth Register (1973-2001).
  • Subgroup analysis focused on 1991-2001.
  • Calculated odds ratios for risk factors associated with spontaneous and indicated preterm births.

Main Results:

  • Preterm birth rate decreased from 6.3% (1984) to 5.6% (2001).
  • Proportion of multiple births born preterm increased from 0.34% (1973) to 0.71% (2001).
  • Maternal smoking strongly associated with spontaneous preterm birth (<28 weeks gestation); advanced maternal age associated with indicated preterm birth (<28 weeks gestation).

Conclusions:

  • Preterm birth rates in Sweden have declined since the mid-1980s.
  • Subtype composition of preterm births in this low-risk population mirrors that of higher-incidence populations.
Abstract

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