Linda A. Hunter, CNM, EdD, is a Clinical Assistant Professor in Obstetrics and Gynecology at the Warren Alpert Medical School of Brown University. She is also in clinical practice on the nurse-midwifery faculty in the Department of Obstetrics and Gynecology at Women & Infants Hospital in Providence, RI.
Issues in Pregnancy Dating: Revisiting the Evidence
Article first published online: 24 DEC 2010
2009 American College of Nurse Midwives
Journal of Midwifery & Womens Health
Volume 54, Issue 3, pages 184–190, May-June 2009
How to Cite
Hunter, L. A. (2009), Issues in Pregnancy Dating: Revisiting the Evidence. Journal of Midwifery & Womens Health, 54: 184–190. doi: 10.1016/j.jmwh.2008.11.003
- Issue published online: 24 DEC 2010
- Article first published online: 24 DEC 2010
- Naegele's rule;
- pregnancy dating;
- ultrasound in pregnancy;
- Rule of Eights
As the end point date in pregnancy, the estimated date of delivery provides guidance for the timing of specific prenatal tests, gauges fetal growth, and informs critical decision making for specific obstetric complications. It is prudent to use the most evidenced-based methods available to accurately determine gestational age. This article explores the accuracy of both menstrual and ultrasound dating techniques and discusses some of the issues and limitations for each method. In addition, a simple formula called the rule of eights can be used to determine a final estimated date of delivery when a discrepancy between menstrual and ultrasound dating occurs.