Health
How to Calculate Gestational Age & Due Date: Naegele’s Rule & Ultrasounds
Just ask and get Editorial Team(Obstetric & Women’s Health)
Updated 2026-09-20
6 min read
Key Takeaway:A practical medical overview of tracking pregnancy milestones, trimester transitions, and delivery dates.
Naegele’s Rule Explained
Naegele’s rule calculates your Estimated Due Date (EDD) by adding 1 year, subtracting 3 months, and adding 7 days to the first day of your last menstrual period (LMP).
Frequently Asked Questions
What percentage of babies are born exactly on their due date?
Only about 4% to 5% of babies arrive on their exact projected due date; most arrive within 2 weeks before or after.