To calculate the expected date of delivery, it is sufficient to know the date of the 1st day of your last menstrual cycle and then you just have to add 7 days and nine months. So, for example if the date of your last menstruation was the 12th of September, the baby should be born on June 19 th.
To calculate the expected date of delivery you simply should decrease 3 months from the date of your last menstruation and then add up to 7 days.
Measuring uterine height with the woman lying on a stretcher may also indicate the probable date of delivery, but another, safer way of knowing when the baby should be born is through an ultrasound performed during prenatal care.
Enter your data in the following calculator and find out when the baby should be born:
How to know your expected delivery date using an ultrasound
During the ultrasound examination an obstetrician can indicate the corrected expected date delivery, which refers to the exact gestational age, which is usually 1 to 2 weeks after the date of your last menstrual period because, after all, if you were menstruating, you couldn't get pregnant those days.
The doctor can calculate your baby's gestational age by observing certain parameters of its growth, because there is a table that indicates the characteristics and what size the baby should present in each week of gestation.
This is the date that you should take most into account for the baby's birth day, but when you choose a normal delivery, that date may vary slightly, because the baby usually decides when it is time to be born. Therefore, the date is only a parameter, because the baby can be born from 37 weeks and not be considered pre-mature, and up to 41 weeks of gestation, without any problem.
However, for safety reasons the doctor can request an appointment each week from 36 weeks and ask you to note of how many times you feel your baby move a day, and if you feel something strange, you should go to the hospital.
How to know the delivery date through the day of conception
Another way of knowing the expected delivery date is through the day of conception, and is a more reliable method in case of in vitro fertilization (IVF), because it is possible to know exactly when fertilization occurred, and consequently the correct gestational age, which lets you know when your baby will be born.