A full-term pregnancy is generally considered to be 40 weeks, which is equivalent to 10 months. However, people often refer to pregnancy as lasting nine months because pregnancy is calculated from the first day of your last menstrual period, which is about 2-3 weeks before fertilization actually occurs.
The number of months a pregnancy lasts can vary slightly depending on the length of each month and when the baby is born. But, a pregnancy is typically considered full-term between 39 and 40 weeks.
