Algorithms for combining menstrual and ultrasound estimates of gestational age: consequences for rates of preterm and postterm birth

BJOG. 2002 Jun;109(6):718-20. doi: 10.1111/j.1471-0528.2002.01068.x.

Abstract

We compared rates of preterm and postterm birth according to six algorithms for gestational age (GA) estimates based on last menstrual period (LMP) and early ultrasound (EUS): LMP alone, LMP if the discrepancy between the two estimates was within 14 days and otherwise EUS (14-day rule), a 10-day rule, a seven-day rule, a three-day rule and EUS alone. In a sample of 44,623 births in a Canadian tertiary hospital, the choice of algorithms makes a substantial impact on both preterm and postterm birth rates, even when EUS was used for discrepancies over two weeks.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms*
  • Female
  • Gestational Age*
  • Humans
  • Infant, Newborn
  • Menstruation / physiology*
  • Obstetric Labor, Premature / diagnosis*
  • Obstetric Labor, Premature / diagnostic imaging
  • Pregnancy
  • Pregnancy, Prolonged*
  • Sensitivity and Specificity
  • Ultrasonography, Prenatal / methods