Let's start by saying this... there is no perfect or fool proof pregnancy calculator BUT there are some general tips that should point you in the right direction and give you a pretty good idea of when you can expect to meet your little one.
1. Generally, your due date is calculated by adding 280 days, or 40 weeks, to the first day of your last menstrual cycle. This is of course assuming you have a 28 day cycle and that you ovulate on day 14. While this trick is a good starting point, it certainly isn't the be-all-end-all since many women do not follow this particular pattern.
As a fun side note, it is also important to note that your menstrual period and ovulation are counted as the first two weeks of this calculation so even though your baby is due at 40 weeks, he/she will actually only be 38 weeks old!
2. If you're charting or know for certain when you ovulated, you can calculate your due date based on ovulation since not everyone ovulates on day 14. This is a much more accurate way to determine when your little one is due because by knowing when you ovulate you are taking part of the "guess-timate" out of the equation. Just add 38 weeks to the date of known ovulation and voilà!
3. Let's say you have no idea when you ovulated because you don't have regular cycles. Never fear! You have the option of a dating ultrasound to help you get the best guess date for when baby may make his/her arrival. If performed within the first 12 weeks, they are usually accurate within 3-5 days. The best time to get the most accurate reading is between 8-11 weeks of gestation.
That being said, we don't feel we would be doing our due diligence if we didn't share with you that ultrasounds may not always be the best option. While research has not shown any reliable evidence that ultrasounds are harmful to a developing fetus, we do not yet have a full grasp on long-term effects. The American Congress of Obstetrics and Gynecologists (ACOG) recommends that because of this, ultrasounds be "performed only for medical reasons."
One more thing. And probably the most important.
Please remember that an estimated due date is just that: an estimate. It is NOT an expiration date. A normal gestational period is anywhere from 37-42 weeks. It is also super important to note that the average first time mom delivers at 41 weeks 1 day. It's perfectly normal to go past your due date and as long as mom and baby are healthy, it's best to let your baby come when he/she is ready to avoid unnecessary complications. Be patient- we promise it's worth the wait💜
So there you have it! We hope this gives you a clearer idea of when you can expect the arrival of your little one. Happy gestating!