Many parents nowadays have researched a lot about calculating the due date.
Pregnancy is a long and challenging process for all pregnant women. They can’t help feeling excited when thinking about the moment meeting their child. That makes them constantly count the date and time!
So, how to calculate pregnancy due date?
For those looking forward to the day when you can hold your baby in your arms, we’re going to provide you very simple ways to estimate the big day in today’s article!
What is Due Date?
Your estimated date of delivery (EDD) is the date when your labor is expected to occur. In fact, the due date is not completely accurate, but only an estimate. To calculate it, the pregnant women need to use their time of conception.
Women who are pregnant with the support of assisted reproductive technology (ART) will be able to estimate the due date more accurate than those pregnant naturally.
See also: When will I get pregnant?
It is often said that pregnancy lasts over 9 months, and this is a period of happiness and excitement that all mothers go through. Any pregnant woman experiences indescribable emotions while carrying a little creature inside her womb and always looks forward to meet them.
Therefore, not only the gender of the baby, but they also have much concern about the due date.
Using the most precise way to calculate pregnancy due date will help the pregnant mother get her mentality prepared well for the upcoming journey. This is very important for a woman during the birthing process. Once getting ready both physically and emotionally, you will feel safe and secure when giving birth.
The due date depends on many factors, keep in mind!
Which Ways to Calculate Pregnancy Due Date?
I. Based on your last menstrual period (LMP)
- For women with regular menstrual cycles:
It’s easy to determine the date of ovulation, time of conception as well as due date with women who have a stable menstrual cycle. Therefore, the simplest and most accurate way to calculate the due date is to add 40 weeks to the first day of the last menstrual period (because the pregnancy period lasts for 38 weeks).
Women with stable menstrual cycles can calculate the due date more accurately
- For women with irregular menstrual cycles:
It is difficult to determine the exact due date if you have an irregular menstrual cycle. At the 13th week, you can choose to do the ultrasound as it can determine the most accurate due date.
Here are some rules to calculate the due date for pregnant women with irregular menstrual cycles:
1/ Naegele’s rule:
The due date = LMP + 9 months + 7 days
This due date calculation is very simple yet the accuracy is quite high, so you can use this rule to estimate your baby’s expected date of birth.
2/ The Mittendorf – Williams’ rule:
With the first pregnancy, the due date = LMP + 9 months + 15 days
In case you’re pregnant from the 2nd time onwards, the due date = LMP + 9 months + 10 days
This rule has been improved – it will offer more accurate results if you provide more necessary information, such as whether this is your first time being pregnant or you’ve been pregnant many times before. Based on the research, the period of the first-time pregnancy is about 288 days.
Those having babies for the second or third time experience the longer period of pregnancy after the first day of your LMP.
Read more: Try a pregnancy tarot spread reading
3/ The Rakesh Parikh rule:
This rule is calculated by adding 9 months and the average period length to the first day of your LMP, and then subtracting 21 days. This calculation is more accurate than the Naegele’s rule for women with irregular menstrual cycles.
II. Based on your ovulation time
If you can determine your ovulation date, then calculating the due date is not as hard as you may think. All you need is to take the day of ovulation and add 38 weeks to it for a relatively accurate date of delivery. However, it is quite challenging to determine the exact date of ovulation.
III. Based on your time of conception
Many women wonder how to know when they are pregnant?
Usually the day of conception will fall on the 11th – 21st day of the last menstrual cycle. In this case, you can estimate your due date by adding 266 days to your day of conception.
Nonetheless, this method also has many difficulties; especially it’s not accurate for women with irregular menstrual cycles.
Is Your Due Date Correct?
The due date is one of the important information for the mothers because it helps them get well prepared to welcome the arrival of their baby. People often think that the pregnancy period is about 38-40 weeks.
But this number is not accurate for all women; that’s why the estimated date of delivery of each is different. There are lots of factors that affect the date of birth of a child such as the fetus development, the mother’s LMP, etc.
According to statistics, about 5% of mothers give birth on the same day as their due date. For others, the date of actual delivery will be about 1 to 2 weeks different from the original prediction. Although the expected date of birth is for reference only, pregnant women should also pay attention to have a good preparation before the children are born.
Your baby will usually be born in the 38th week from conception.
Since we hardly tell the exact time of conception, your due date is usually around the 40th week from the first day of your last period (LMP).
Finding the most accurate way to calculate pregnancy due date is still a concern for most pregnant women. The above methods has certain advantages and limitations; therefore, the best way to predict your labor date is to have regular pregnancy ultrasounds to get an estimate of the due date as well as advice from the doctor.
Leave a comment below if having any question!