What to Expect: How Does Your Doctor Really Calculate Your Due Date?

Your estimated due date (EDD) is circled in red on your calendar, and you’re probably counting down the days on your app. But it’s anyone’s guess when baby will actually make her debut (which is why it’s called “estimated”). Since only 5 perfect of moms actually deliver on their EDD, and only 30 percent of babies stay put for around 40 weeks, it’s not exactly a precise science.