The first thing we want to know after finding out that we are pregnant is to know the date our baby will be born , or when we are due. This is what is known as the probable date of delivery (PPD), which is calculated from the first day of the last menstruation, or date of the last menstruation (LMP).
This date is calculated using Naegele’s Rule, which consists of subtracting three months from the first day of your last menstrual period, and then adding seven days. The result is your due date.
For example, if the date of your last period was February 1, 2021, we subtract three months to find the month (November 1) and add 7 days to find the probable date of delivery (PPD), which will be November 8. November 2021.
The pregnancy calculator that you can see below is based on this data, and will offer you the result that it would give you if you did the formula.
How does the pregnancy calculator work?
It is a simple online application in which you must enter the date of the first day of your last menstruation. Once entered, the pregnancy calculator offers you the due date and the day of the week .
How to calculate the weeks of pregnancy
The first day of the date of your last menstrual period is the day that the weeks of gestation begin to be counted. Week 1 is the starting point of pregnancy. From there 40 weeks are counted (280 days of gestation), or 38 weeks from the moment of fertilization. Check out more interesting topics on our site Faith Blog.
Since in most women it is not possible to calculate the exact day of ovulation , the first day of the last period is taken as the date of onset of pregnancy .
The gestagram or pregnancy wheel is another tool that allows you to know the probable date of delivery, as well as the weeks of gestation, the weight and the size of the baby.
In any case, as we have already mentioned in Babies and more, the expected date of delivery should be called the unlikely date of delivery , because very few women actually give birth on that day and therefore the results of the pregnancy calculator should always be taken as an approximation to the day of your new maternity and not as a “binding contract”.
Please note that this is an estimated date and is based on regular 28-day cycles. Your baby will most likely be born between two weeks before and after your due date.
Pregnancy week by week: from week 1 to week 40
trimesters of pregnancy
Finally, as you know, in addition to weeks, pregnancy is divided into three trimesters .
- The first trimester of pregnancy covers from fertilization to week 13 .
- The second trimester of pregnancy is from week 14 to week 27 .
- The third trimester of pregnancy is from week 28 to week 40 .