Pregnancy is often referred to as nine months long, but this is a simplification. A full-term pregnancy is actually 40 weeks long, or 280 days. This equates to 10 months, not nine. The reason for the common misconception is that 36 weeks of pregnancy translates to nine calendar months. This is because, on average, a calendar month is 30 days and 10 hours.
Therefore, while a full-term pregnancy is 10 months, the first 4 weeks of pregnancy fall within the last month of the woman's previous cycle, resulting in a total of nine calendar months from the point of conception to birth.
This is why many people commonly refer to pregnancy as being nine months long. However, it is essential to remember that a full-term pregnancy is 40 weeks long, and counting from the first day of a woman's last menstrual period, it encompasses 10 calendar months.
