Your healthcare provider will definitely give you an estimated due date (EDD), but you must not rely on this 100%. What your doctor will predict is just an estimate or a best guess, and you don’t even have to wait until he/she can do so, calculate your due date now, using our due date calculator.
When Is My Baby Due – Learn How to Calculate Your Due Date
You too can calculate your due date without the help of a doctor or an online calculator. Just like all due date calculators, your doctor is very likely to work out your due date or your EDD based on Naegele’s rule. Dr Naegele was a German scientist who devoted his time studying the human gestation period. According to this rule, the average pregnancy runs for 266 days or 38 weeks from conception date, or 280 days (40 weeks) from the first day of last menstrual period (LMP).
To calculate your due date using Naegele’s law, or findings, just subtract 3 months from the first day of your last menstrual period, add one year, and add 7 days to get your due date.
Below is a sample calculation:
If first day of your last period is 08/10/2013, subtract 3 months to get 05/10/2013.
Add one year to 05/10/2013 to get 05/10/2014.
Add 7 days to 05/10/2014 to get 05/17/2014, which is your due date.
When Is My Baby Due – Why It Is Only an Estimated Due Date (EDD)
The Naegele rule is based on the assumption of an average cycle of 28 days and 14th day ovulation. The truth is that not all women have 28 day cycles and not all ovulate exactly on the 14th day. In such cases, the EDD is very likely to be inaccurate.
Other than the average cycle, there are other factors that can affect your due date, such as genes. Studies have shown how genes can affect a woman’s due date, for example, a family history of preterm deliveries can affect most women in that family. In the same way, a family history of overdue pregnancies can lead to an overdue pregnancy.
Other studies have suggested that Caucasian women have longer gestation periods when compared to their African and Asian counterparts. Also, women who have never given birth before tend to carry longer pregnancies.
When Is My Baby Due – There Is No Known Way To Guarantee Your Due Date
Regrettably, there is no guaranteed way to predict your due date. An early ultrasound might have better results, especially when a woman cannot recall her LMP, or is unaware of her average cycle. Women with irregular cycles will not be able to calculate their due dates and will have to rely on ultrasounds too.
However, you still have a chance of delivering on your given due date, 3-5% of all pregnant women tend to deliver exactly on their due dates, while the 70% deliver 2-3 weeks later. 25% will deliver one week later or earlier than their EDD.