Trends in preterm birth in twin pregnancies in Victoria, Australia, 2007–2017

Renée J. Burger*, Sofieke Temmink, Dagmar Wertaschnigg, Wessel Ganzevoort, Maya Reddy, Mary Ann Davey, Euan Morrison Wallace, Ben Willem Mol

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


Background: Preterm birth is a major cause of perinatal morbidity and mortality worldwide. In many countries, the preterm birth rate in women with a multiple pregnancy is increasing, mostly due to an increase in iatrogenic preterm birth. Aims: To investigate trends in preterm birth in twin pregnancies in Victoria, Australia, in relation to maternal and perinatal complications. Materials and methods: We conducted a retrospective population-based cohort study in all women with a twin pregnancy who delivered at or after 20 weeks of gestation in the state of Victoria, Australia between 2007 and 2017. Annual spontaneous and iatrogenic preterm birth rates were calculated and trends analysed. Incidence of adverse pregnancy outcomes, maternal complications and risk factors for preterm birth were analysed. Results: We studied 12 757 women with a twin pregnancy. Between 2007 and 2017 the preterm birth rate increased from 641/1231 (52%) to 803/1158 (69%), mainly due to an increase in iatrogenic preterm birth from 342/1231 (28%) to 567/1158 (49%). This was irrespective of the presence of pregnancy complications. Our study showed neither a decrease in perinatal mortality from 28 weeks of gestation nor in preterm average weekly prospective stillbirth risk. Conclusion: Preterm birth rates in twins in Victoria are increasing, mainly driven by an increase in iatrogenic preterm birth. This occurred both in complicated and non-complicated twin pregnancies, and has not been accompanied by reduction in perinatal mortality from 28 weeks.

Original languageEnglish
Pages (from-to)55-62
Number of pages8
JournalAustralian and New Zealand Journal of Obstetrics and Gynaecology
Issue number1
Early online date20 Aug 2020
Publication statusPublished - Feb 2021

Bibliographical note

Funding Information
NHMRC Investigator Grant. Grant Number: GNT1176436
NHMRC Program Grant. Grant Number: APP1113902
Partnership Grant. Grant Number: APP1151853
Paracelsus Medical University Salzburg, Austria (PMU Research Fund). Grant Number: L‐18/02/006‐WET


  • Australia
  • pregnancy complications
  • preterm birth
  • twin pregnancies
  • Victoria
  • RISK
  • TERM


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