Gestational vs Embryonic Age
Gestational age counts from the first day of the last menstrual period (LMP). Embryonic age (conceptional age) counts from conception, about 2 weeks later. Doctors use gestational age for consistency. An 8-week gestational age embryo is actually 6 weeks from conception.
Ultrasound Dating
Early ultrasound (6-12 weeks) is the most accurate dating method, accurate to within 3-5 days. It measures crown-rump length (CRL) or other parameters. If ultrasound differs from LMP by more than 7 days, doctors typically use ultrasound dating as it's more reliable.
Why Gestational Age Matters
Determines appropriate prenatal tests and screenings, monitors fetal growth, helps time delivery, assesses viability in high-risk situations, and guides medical interventions. Accurate dating is crucial for proper prenatal care.
Quick Tips
- BMI alone doesn't reflect overall health
- TDEE varies based on activity level
- Consult a healthcare professional for medical decisions
Frequently Asked Questions
Early ultrasound (6-12 weeks) is more accurate, especially if cycles are irregular.
LMP is more reliably known than conception date. Standardization helps consistency.
Doctors may revise based on early ultrasound if it differs significantly from LMP dating.
First trimester (6-13 weeks). Accuracy decreases in later trimesters.
Ultrasound measurements will be used to establish gestational age.