When am I due?

"When am I due?" is probably the number one question on your mind as soon as you find out you're pregnant. Find out how your due date is calculated here!

Every month, typically 14 days before the first day of your period, one of your ovaries releases an egg (ovum). The sperm has 24-48 hours to fertilize the egg. If the egg is not fertilized, conception does not occur and you will get your period on schedule. If you don't... congratulations! One of the first things you - and everyone else - will want to know is: when are you due?

Your healthcare provider will probably refer to that magic date as your EDD, meaning estimated due date (though it is also sometimes called the outdated term EDC - Estimated Date of Confinement). Keep in mind that this date is only an estimate.

The Calculation
The standard method to calculate your official due date is to count ahead 280 days from the first day of your last menstrual period (LMP). A second method for calculating your due date you can probably do in your head! Just take the date (day number) of your LMP and add 7, then subtract three months. For example:

LMP:April 14 Add 7:April 21 (14+7) Count back 3 months:January 21

Where these numbers come from
These methods - and our due date calculator - assume you have a 28-day menstrual cycle:

Day number 1	Your period begins (LMP)
Day number 14	Conception occurs
Day number 28	Next period due Pregnancy tests might be accurate this early You're 1 month pregnant!

The 280-days rule is based on 266 days of gestation (length of actual typical pregnancy, from conception to birth), plus the previous two weeks - from the first day of the last menstrual period until conception, for a total of 280 days.

The notion that there are exactly 14 days after LMP and before conception, however, is not accurate for everyone. If your cycle is typically 31 days, and conception occurs 14 days before your next period is due (not simply 14 days after your last period), there remains a three day discrepancy (31 - 14 - 14 = 3). In this case, that could mean that you might expect your child's arrival three days later and still your baby would be be right on time. The same holds true if your cycles are shorter - you might deliver sooner.

If your cycles are longer or shorter than 28 days, make sure to let your healthcare provider know. While she or he may not adjust your EDD, it's a good thing to keep in mind if the fetal heartbeat is not heard quite as early as expected or if you go post-dates (overdue).

Other Methods
Other ways to verify your baby's gestational age and your due date - with absolutely no guarantees here, either - include:

• Working out your date of conception based upon BBT, cervical mucus, timing of intercourse
• Remembering when you first got a positive pregnancy urine test. (In ideal circumstances, and using first morning urine with the strongest concentration of hCG, these home tests can be positive as early as 10 days after conception. It's usually more accurate to wait until at least the day your period is due before testing to lessen the chances of a false negative.)
• Testing the hCG (human chorionic gonadotropin) levels in your blood - generally should be at least 5 mIU/ml in early pregnancy, and the level doubles about every two days.
• When pregnancy symptoms (tender breasts, nausea) first began
• Analyzing the results of types of prenatal tests, such as ultrasounds and AFP screens.
• When the fetal heart was first heard with Doppler and/or fetoscope
• Height of fundus (top of uterus) at various stages of pregnancy
• When you felt the first movements
• When you first felt a strong kick
• Internal cervical examination

You must also take into account whether or not this is your first or later pregnancy. This will matter both for comparison's sake as well as because you may feel certain symptoms sooner (such as fetal movement) the second time around.

There is no perfect way of predicting when your baby will arrive. Pregnancy itself is a great exercise in patience and uncertainly - skills you're going to need as a parent, anyhow! But for now, relax, enjoy your pregnancy and know that no matter how far away that due date seems, it will be here sooner than you think!

Jump to the due date calculator now!

Also see:
The Weekly calculator
The Months calculator