How are pregnancy weeks calculated?

Weeks are counted from the first day of your last menstrual period (LMP). This means the first 2 weeks are technically before conception.

How many weeks does a pregnancy last?

A normal pregnancy lasts 40 weeks (280 days) from the LMP. The baby is considered full-term between weeks 37 and 42.

First trimester: weeks 1-12. Second trimester: weeks 13-26. Third trimester: weeks 27-40.

Calcule em qual semana de gravidez você está

Método de cálculo

Data da última menstruação