1st trimester (Weeks 1–13)
Early development, implantation, morning sickness, first prenatal visit planning.
- • Weeks 4–6: missed period is common
- • Weeks 8–12: many people schedule first scans
- • Week 12–13: end of 1st trimester
2nd trimester (Weeks 14–27)
Energy may improve, bump grows, anatomy scan window often occurs mid-trimester.
- • Weeks 18–22: anatomy scan window (common)
- • Weeks 20–24: noticeable movements may start
- • Week 27: end of 2nd trimester
3rd trimester (Weeks 28–40)
Growth accelerates, preparing for delivery, appointments may become more frequent.
- • Week 32–36: planning hospital bag & birth plan
- • Week 37+: term window begins
- • Week 40: EDD (estimate)
Explore Pregnancy by Week
Select your pregnancy week to see baby development, symptoms, and tips.
What is “40 weeks” based on?
Pregnancy length is commonly estimated as about 280 days (40 weeks) starting from the first day of your last menstrual period (LMP). This method is used because ovulation timing varies, while the LMP is easier to identify. Doctors and midwives worldwide use this standard for initial due date estimates.
Is it normal to deliver before/after the EDD?
Yes. The estimated due date (EDD) is only an estimate, not a guarantee. Most babies are born within two weeks before or after the due date. Only a small percentage of births happen on the exact EDD, which is why doctors often refer to a “delivery window.”.