Guideline for Assessment of the “Best Estimate” of Gestational Age

Accurate assessment of gestational age is crucial:

  1. to determine viability of extreme preterm birth
  2. to properly interpret maternal serum screening for aneuploidy
  3. to prevent post term induction of labour and
  4. to optimize obstetric care including avoiding inappropriate perinatal interventions.

Consistent approaches to gestational age assessment must also be taken to optimize accuracy.

This provincial guideline has been revised to reflect the recommendations of national professional organizations and local experts, within the context of Nova Scotia perinatal care provision. As such, these guidelines may differ from those found in other jurisdictions. The RCP acknowledges the Divisions of Maternal Fetal Medicine (MFM) and Neonatal Perinatal Medicine (NPM) at the IWK Health Centre, for their collaboration in producing this guideline.

Date Revised: 
June, 2020