Your pregnancy, week by week
Tap any week to see how big your baby is, what's developing, how you may feel and one gentle tip for that week.
Reviewed against ACOG, NHS and WHO guidance · Updated November 2026
First trimester · Weeks 1–13
Second trimester · Weeks 14–27
Third trimester · Weeks 28–40
How pregnancy weeks are counted
Pregnancy is counted from the first day of your last menstrual period, not from conception. That's why a full-term pregnancy is about 40 weeks, and why you're not actually pregnant during weeks 1 and 2.
Babies born between 39 weeks and 40 weeks 6 days are considered full term. Sizes listed are averages — your scan results may differ, and that's usually normal.
Carry this guide in your pocket
Mamivaa is a free pregnancy app with a week-by-week tracker, vitamin and water reminders, a food scanner and a baby checklist.
Start freeThis guide offers general information and does not replace advice from your doctor or midwife. If something feels wrong, contact your provider or emergency services.