how many months is the average pregnancy?
This means a "typical" pregnancy likely lasts 38 weeks and 2 days — or 8 months, 24 days, and 16 hours. — if you're counting from fertilization of an egg. (Note: If you're counting from the last menstrual period, which is a very imprecise way to measure pregnancy duration, it's more like 40 weeks and 5 days.)