Last updated: March 2026
Understanding Your Estimated Due Date
Your estimated due date (EDD) is a target, not a deadline. Think of it as the center of a four-week window — most babies arrive between 38 and 42 weeks, with the most common delivery window being 39-41 weeks.
Each trimester brings distinct changes. The first trimester (weeks 1-12) is when all major organs form. Morning sickness is common and energy levels may dip. The risk of miscarriage drops significantly after week 12.
The second trimester (weeks 13-27) is often called the "golden period" — morning sickness typically fades, energy returns, and you start feeling baby movements (quickening) around weeks 18-22. The anatomy scan at weeks 18-20 checks baby's development.
The third trimester (weeks 28-40) focuses on growth and preparation. Baby gains most of their birth weight during these final weeks. Braxton Hicks contractions may begin as the body prepares for labor.
Your healthcare provider will monitor you more closely as you approach your due date. Most providers discuss induction between 41-42 weeks if labor hasn't started naturally, though every situation is unique.
Frequently Asked Questions
When is my due date?
Your due date is estimated at 40 weeks (280 days) from the first day of your last menstrual period. Enter your date above to see your specific due date, along with trimester progress and key milestones.
Can my due date change?
Yes. Your due date may be adjusted after an ultrasound, especially if it differs from the LMP calculation by more than a week. First-trimester ultrasounds are the most accurate for dating.
What does 'full term' mean?
Full term is defined as 37-42 weeks of pregnancy. Early term is 37-38 weeks, full term is 39-40 weeks, late term is 41 weeks, and post-term is 42+ weeks. Most providers recommend delivery by 41-42 weeks.
What trimester am I in?
The first trimester spans weeks 1-12, the second trimester weeks 13-27, and the third trimester weeks 28-40. Each trimester brings different developmental milestones and physical changes.
How do I count pregnancy weeks?
Pregnancy weeks start from the first day of your last period, not from conception. So during 'week 1,' you aren't actually pregnant yet — conception typically occurs around week 2-3.