Pregnancy month by month
Pregnancy lasts about 9 months, or 40 weeks from the first day of your last period. Months 1 to 3 are the first trimester, 4 to 6 the second and 7 to 9 the third. Choose a month to see your baby's development, your symptoms and what to do.
| Month | Weeks | Trimester | Baby by the end of the month |
|---|---|---|---|
| 1 month pregnant | 1 to 4 | First | About the size of a poppy seed |
| 2 months pregnant | 5 to 8 | First | About the size of a raspberry |
| 3 months pregnant | 9 to 13 | First | About the size of a lemon |
| 4 months pregnant | 14 to 17 | Second | About the size of a pomegranate |
| 5 months pregnant | 18 to 22 | Second | About the size of a papaya |
| 6 months pregnant | 23 to 27 | Second | About the size of a cabbage |
| 7 months pregnant | 28 to 31 | Third | About the size of a coconut |
| 8 months pregnant | 32 to 35 | Third | About the size of a honeydew melon |
| 9 months pregnant | 36 to 40 | Third | About the size of a watermelon |
Why doctors count in weeks, not months
Calendar months have 28 to 31 days, so they never line up neatly with pregnancy weeks. Doctors count in weeks because development changes quickly, and tests and scans are timed to specific weeks. For week-by-week detail, see our pregnancy week-by-week guide, or work out your dates with the due date calculator.
Questions about pregnancy months
How many weeks is 9 months pregnant?
A full-term pregnancy is 40 weeks from the first day of your last period, which is a little over 9 calendar months. Month 9 covers weeks 36 to 40.
Is pregnancy 9 or 10 months?
Counted in calendar months, it is just over 9 months. Some people say 10 months because 40 weeks divided into 4-week blocks makes 10. Doctors avoid the confusion by counting in weeks.