Pregnancy is typically calculated from the first day of your last menstrual period (LMP). From that date, pregnancy usually lasts about 40 weeks (280 days), although it can range from 37 to 42 weeks

. To find out how many weeks pregnant you are from your last period, you count the number of weeks that have passed since the first day of your last menstrual cycle up to the current date. For example, if your last period started 8 weeks ago, you are considered 8 weeks pregnant. Key points:

• Pregnancy weeks start counting from the first day of your last period, which is considered week 0

• The typical pregnancy duration is about 40 weeks from the LMP

• The first two weeks of pregnancy actually cover your menstrual period and ovulation before conception occurs

• Your due date is estimated by adding 280 days (40 weeks) to the first day of your last period

• Ultrasound scans, usually done around 12 weeks, can provide a more accurate estimate of how many weeks pregnant you are

In summary, to know how many weeks pregnant you are from your last period, simply count the weeks from the first day of your last menstrual period to today. This count gives your gestational age, which is the standard way healthcare providers track pregnancy progress