All About Due Dates
What are due dates? A due date is not actually when we expect your baby to be born!
Due dates are best described as the date that is 266 days from conception or 280 days from your last menstrual period. Confusing, we know. Only 4% of people give birth on their due date, while more than 70% give birth between 39+4 weeks and 42 weeks.
If this is your first baby, you’re more likely to go past your due date!
Read more about pregnancies that go past their due date here.
How are due dates determined? This is up to you and your medical provider!
LMP (Last Menstrual Period): This involves counting 40 weeks forward from the first day of your last menstrual period. This is an effective method for people who have regular cycles with consistent durations. If someone has an irregular period this dating method becomes less reliable
Dating Ultrasound: This method involves an ultrasound in your first trimester that measures the size of your baby. Though second trimester ultrasounds can also be used to determine due dates, they are less accurate as there is much more variance in baby sizes and growth after the first trimester.
IVF and IUI: In assisted conception, the date of conception is very accurate. You and your care provider can count 266 days forward from your date of conception to determine your due date.
Why have a due date then?
Due dates allow your care provider to plan your care. They are used to determine when certain time-specific tests should be offered and they are also used to determine whether baby is coming early, late, or right on time. If an induction of labour needs to be discussed, having an accurate due date is crucial in making sure baby doesn’t come too early. If your baby is taking its sweet time coming earth-side, having an accurate due date helps us determine how long we can safely keep waiting. So don't clear your calendar yet, trust that your baby and your body will decide when it's the best time for baby to arrive.
Check out our Recommended Reading for some great resources to fill the time while you wait for your little one to arrive.