How long does pregnancy last?
Pregnancy is counted from the first day of your last menstrual period. This means an extra 2 weeks are counted at the beginning of your pregnancy when you aren’t actually pregnant. So pregnancy lasts 10 months (40 weeks)—not 9 months—because of these extra weeks.
About Ask ACOG
Do you have a question about women’s health? ACOG is here with answers to help you stay healthy. Browse all questions.Go
Published: October 2020
Last reviewed: October 2020