Committee opinion no 611: method for estimating due date

Obstet Gynecol. 2014 Oct;124(4):863-866. doi: 10.1097/


: Accurate dating of pregnancy is important to improve outcomes and is a research and public health imperative. As soon as data from the last menstrual period, the first accurate ultrasound examination, or both are obtained, the gestational age and the estimated due date should be determined, discussed with the patient, and documented clearly in the medical record. Subsequent changes to the estimated due date should be reserved for rare circumstances, discussed with the patient, and documented clearly in the medical record. When determined from the methods outlined in this document for estimating the due date, gestational age at delivery represents the best obstetric estimate for the purpose of clinical care and should be recorded on the birth certificate. For the purposes of research and surveillance, the best obstetric estimate, rather than estimates based on the last menstrual period alone, should be used as the measure for gestational age.

Publication types

  • Review

MeSH terms

  • Advisory Committees / standards
  • Evidence-Based Medicine
  • Female
  • Fetal Development / physiology
  • Gestational Age*
  • Humans
  • Menstrual Cycle / physiology*
  • Physical Examination / standards*
  • Practice Guidelines as Topic*
  • Predictive Value of Tests
  • Pregnancy
  • Pregnancy Trimester, First
  • Pregnancy Trimester, Second
  • Pregnancy Trimester, Third / physiology*
  • Societies, Medical / standards
  • Time Factors
  • Ultrasonography, Prenatal*