Congratulations on your pregnancy! Nothing compares to finding out you have a new little one on the way. Once you’ve had a moment or two to process the excitement, you’ll undoubtedly wonder when you’re due. If you’ve done this before, you know that it takes a few more weeks before you can see a doctor to confirm and find out “how pregnant” you really are. If you’re new to this, the next few weeks could be the longest weeks of your life (until the last trimester). But fear not, there are a few ways to figure out your due date.
Most pregnancies last 40 weeks from the date of your last period or 38 weeks from conception. So using these dates may give you an idea of how long you can expect to be expecting. If you have an idea of either of those dates, a few simple additions is all it takes to figure out your approximate due date.
Calculating your due date if you have a regular 28-day cycle
If you’re fortunate enough to have a regular period cycle, the most straightforward method is to count backward from your last period. You’ll count back two weeks and mark that day as the start of your pregnancy. Add 40 weeks, and you have your estimated due date. This is the method used by most doctors.
Example:
Your last period started on March 15. So count back two weeks and mark the date (March 1) as the start of your pregnancy.
Now, add 40 weeks.
Your Estimated Due Date = December 6
Calculating your due date based on ovulation
Suppose you track your ovulation symptoms or use ovulation strips to keep track of fertility. In that case, you may use your conception date to calculate your due date by adding 38 weeks to the conception date.
For example:
Your conception date is March 15. Add 38 weeks.
Your Estimated Due Date = December 6
Calculating your due date with an ultrasound scan
If your periods are irregular or you’re using a birth control that makes you miss periods, you’ll probably have to rely on your first ultrasound to find out when you’re due. A doctor will generally see you about 4 weeks after your missed period. That gives your body enough time to produce enough pregnancy hormones and start the growth process in preparation for your baby. The ultrasound method uses the size of your uterus and other measurements to determine how far along you are and then automatically calculates a due date.
Can my due date change? Yes!
Even the “most accurate” method can be flawed because we are all a little different. As your baby grows, new information your doctor finds may alter your due date. So keeping the routine appointments you schedule with your provider is very important.
Now that you have an idea of when to expect your little one’s arrival, you can start planning and preparing for your pregnancy journey and for life as a mom!
