How long does pregnancy last?
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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.
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Published: October 2020
Last reviewed: October 2020
Copyright 2020 by the American College of Obstetricians and Gynecologists. Read copyright and permissions information.
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