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What is the due date if I'm Pregnant?
How is my due date determined?
What is the estimated due date?
What is estimated due date (EDD)?
Use the pregnancy due date calculator to work out roughly when your baby is due to be born, working from the first day of your last period.
- Overview
- How can I calculate my due date?
- What if I don’t know the date of my last menstrual period?
- What if I have irregular periods or long cycles?
- What does it mean if my doctor changes my due date?
- What is the ultrasound date, and why is it different from my due date?
- Article sources
If you’re trying to calculate your approximate due date, there are different ways you can do so. You can try using Naegele’s rule or a pregnancy wheel to get an idea.
Pregnancy lasts an average of 280 days (40 weeks) from the first day of your last menstrual period (LMP). The first day of your LMP is considered day one of pregnancy, even though you probably didn’t conceive until about two weeks later (fetal development lags two weeks behind your pregnancy dates).
Read our report on the 13 best pregnancy iPhone and Android apps of the year here.
Calculating your due date isn’t an exact science. Very few women actually deliver on their due date, so, while it’s important to have an idea of when your baby will be born, try not to get too attached to the exact date.
Naegele’s rule
Naegele’s rule involves a simple calculation: Add seven days to the first day of your LMP and then subtract three months. For example, if your LMP was November 1, 2017: 1.Add seven days (November 8, 2017). 2.Subtract three months (August 8, 2017). 3.Change the year, if necessary (to the year 2018, in this case). In this example, the due date would be August 8, 2018.
Pregnancy wheel
The other way to calculate your due date is to use a pregnancy wheel. This is the method that most doctors use. It’s very easy to estimate your due date if you have access to a pregnancy wheel. The first step is locating the date of your LMP on the wheel. When you line up that date with the indicator, the wheel displays your due date. Remember that the due date is only an estimate of when you will deliver your baby. The chances of actually having your baby on that exact date are very slim.
This is more common than you’d think. Luckily, there are ways to figure out your due date when you can’t remember the first day of your LMP:
•If you know you had your LMP during a particular week, your doctor can estimate your due date accordingly.
Some women have cycles that are consistently longer than the average 28-day cycle. In these cases, a pregnancy wheel can still be used, but some simple calculations are necessary.
The second half of a woman’s menstrual cycle always lasts for 14 days. This is the time from ovulation to the next menstrual period. If your cycle is 35 days long, for example, then you probably ovulated on day 21.
Once you have a general idea of when you ovulated, you can use an adjusted LMP to find your due date with a pregnancy wheel.
For example, if your menstrual cycle is usually 35 days long and the first day of your LMP was November 1:
1.Add 21 days (November 22).
2.Subtract 14 days to find your adjusted LMP date (November 8).
Your doctor may change your due date if your fetus is significantly smaller or larger than the average fetus at your particular stage of pregnancy.
Generally, your doctor orders an ultrasound to determine the gestational age of your baby when there’s a history of irregular periods, when the date of your LMP is uncertain, or when conception occurred despite oral contraceptive use.
An ultrasound allows your doctor to measure the crown-rump length (CRL) — the length of the fetus from one end to the other.
During the first trimester, this measurement provides the most accurate estimation for the age of the baby. Your doctor may change your due date based on the ultrasound measurement.
This is most likely to occur in the first trimester, especially if the date estimated by the ultrasound differs by more than one week from the date estimated by your doctor based on your LMP.
In the second trimester, an ultrasound is less accurate and your doctor probably won’t adjust your date unless the estimates vary by more than two weeks.
When a doctor performs an ultrasound, they write a report on the findings and include two estimated due dates. The first date is calculated using the date of the LMP. The second date is based on the ultrasound measurements. These dates are rarely the same.
When your doctor evaluates the ultrasound results, they’ll determine whether or not these dates are in agreement. Your doctor probably won’t change your due date unless its significantly different from your ultrasound date.
If you have more ultrasounds, each ultrasound report will contain a new due date based on the most recent measurements. An expected due date shouldn’t be changed based on measurements from a second- or third-trimester ultrasound.
Due date estimations are more accurate earlier in pregnancy. Later ultrasounds are helpful in determining whether the fetus is growing well but not for determining the age of the fetus.
•ACOG reinvents the pregnancy wheel: Launches new due date app. (2016). https://www.acog.org/About-ACOG/News-Room/News-Releases/2016/ACOG-Reinvents-the-Pregnancy-Wheel
•Avoid fetal “keepsake” images, heartbeat monitors. (2014). https://www.fda.gov/ForConsumers/ConsumerUpdates/ucm095508.htmTrusted Source
•Calculating a due date. (n.d.). http://www.hopkinsmedicine.org/healthlibrary/conditions/pregnancy_and_childbirth/calculating_a_due_date_85,P01209/
•Calculating your estimated due date. (2014). https://my.clevelandclinic.org/health/diseases_conditions/hic_Am_I_Pregnant/hic_Calculating_Your_Estimated_Due_Date
•Due date calculator. (n.d.). http://www.marchofdimes.org/pregnancy/calculating-your-due-date.aspx
•Pregnancy due date and gestational age calculator. (n.d.). http://www.perinatology.com/calculators/Due-Date.htm
The due date, also known as the estimated date of confinement, is an estimation of when a pregnant woman will deliver her baby. While the due date is often estimated as a single date, it can be helpful to consider a range of due dates, since only 4% of births occur on the estimated due date. 1
Apr 3, 2019 · Positive pregnancy test? Trying to conceive? Our pregnancy Due Date Calculator can help you work out your estimated due date or when your baby might arrive.
The estimated due date (EDD or EDC) is the date that spontaneous onset of labor is expected to occur. The due date may be estimated by adding 280 days ( 9 months and 7 days) to the first day of the last menstrual period (LMP).
Mar 19, 2023 · How Is My Due Date Determined? Normally, your due date is 280 days (40 weeks or about 10 months -- also known as 10 lunar months) from the first day of your last period.
A typical pregnancy lasts, on average, 280 days, or 40 weeks—starting with the first day of the last normal menstrual period as day 1. An estimated due date can be calculated by following steps 1 through 3: First, determine the first day of your last menstrual period.