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How many weeks pregnant am I?


Updated May 16, 2014

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Seven Month Ultrasound

Ultrasound around the seventh month.

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How many weeks pregnant?
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See also: How big is my baby?

Question: How many weeks pregnant am I?

Pregnancy is, on average, 40 weeks or 280 from the first day of your last menstrual period (LMP).

Answer: The number of weeks you are pregnant depends on the date of your last period. You technically ovulate near what would be called week two of pregnancy, but this is how the vast majority of people, your doctor or midwife included, calculate pregnancy length. Your due date is week 40.

To calculate how many weeks you are you can use a calendar. List your due date or the first day of your last period. Count forward for LMP or backwards from your due date to determine which week is when. (Hint: Same day of the week!) You can write this on your calendar or use a pregnancy weeks calculator.


LMP: January 1
Week 1: January 8
Week 2: January 15
Week 20: May 21
40 Weeks (Due Date): October 8

Did you know that as many as 26% of women have their due dates changed in pregnancy? Do you know what to ask before letting them change your due date? (You may also want to figure out from your due date, when you got pregnant.)

Weeks of Pregnancy


Declercq ER, Sakala C, Corry MP, Applebaum S, Herrlich A. Listening to Mothers III: Pregnancy and Childbirth. New York: Childbirth Connection, May 2013.

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