Obstetric (Pregnancy)

NCBI Bookshelf. John A. Morgan ; Danielle B. Authors John A. Morgan 1 ; Danielle B.

Pregnancy Scans performed during the first 12 weeks of pregnancy are generally within 3 – 5 days of accuracy. The most accurate time for the due date calculation​.

Read terms. Pettker, MD; James D. Goldberg, MD; and Yasser Y. This document reflects emerging clinical and scientific advances as of the date issued and is subject to change. The information should not be construed as dictating an exclusive course of treatment or procedure to be followed. 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 EDD should be determined, discussed with the patient, and documented clearly in the medical record.

Subsequent changes to the EDD 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.