Preterm birth in pregnancies complicated by major congenital malformations: a population-based study

Stephanie E. Purisch, Emily A. DeFranco, Louis J. Muglia, Anthony O. Odibo, David M. Stamilio

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


Objective: The objective of the study was to estimate and compare the relative risk of preterm birth (PTB) in pregnancies complicated by 1 or more of 8 major congenital malformations (MCMs). Study Design: This was a population-based cohort study of the birth database of the Missouri Department of Health (1989-1997) including 678,693 singleton live births. Outcomes included a binary composite variable of any MCM and the following 8 individual malformations: spina bifida, diaphragmatic hernia, renal agenesis, other urogenital anomaly, tracheoesophageal fistula/esophageal atresia, omphalocele/gastroschisis, cardiac defect, and cleft lip/palate. Chromosomal anomalies were excluded. Logistic regression analyses assessed the association between malformations and PTB. Results: The risk of PTB increased significantly and to varying degrees for each malformation. In pregnancies with any MCM, there was an increased prevalence (11.5%) and relative risk (adjusted odds ratio [adjOR] 3.2 [95% confidence interval (CI) 2.9 to 3.6]) of PTB at less than 35 weeks' gestation. The magnitude of risk increase was greatest at the earliest gestational ages: adjOR 4.8 (95% CI, 4.0 to 5.7) at less than 28 weeks. Pregnancies with multiple malformations were at highest risk for PTB: adjOR 8.0 [95% CI, 4.6 to 14.1]. Conclusion: MCMs significantly increase PTB risk. The risk varies by malformation type and is higher with multiple malformations.

Original languageEnglish
Pages (from-to)287.e1-287.e8
JournalAmerican Journal of Obstetrics and Gynecology
Issue number3
StatePublished - Sep 2008


  • congenital malformations
  • prematurity
  • preterm birth risk

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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