The time that a fetus has been developing in the mother's womb from the date of conception is known as the gestational, or fetal, age.
However, doctors and obstetricians typically calculate the fetal age from the onset of your last menstrual cycle, not from the estimated conception date. This is guaranteed to be inaccurate because the fetus cannot be 2 weeks old even before it has been conceived!
So, what is the reason for this practice?
As it happens, the reasons are of a practical nature: the onset of the menstrual cycle is more certain than the conception date. The conception occurs approximately 14 days after the onset of the menstrual cycle. However, the exact conception date is hard to tell because the menstrual cycle can be irregular; furthermore, with sperm living for about 2 days and ovum livings for approximately 3 days there is no telling as to when exactly does it happen.
Because of the uncertainly of the exact conception date, obstetricians prefer to calculate the fetal age from the first day of the last menstrual cycle.
If you'd like to more accurately calculate the gestational age, here is how to do it:
1. Count the number of weeks since the onset of your menstrual cycle. This tells you how far along are you in the pregnancy.
2. Subtract 2 weeks to get the estimated fetal age of your baby.
For example, if you are 20 weeks into your pregnancy, the gestational age of your baby is 18 weeks. Knowing this is also useful when you want to calculate the likely conception date from the known date of birth.
Dr Alex Davidovic and his team are the authors of the accurate pregnancy calculator, which computes the due date, the likely conception date, trimesters, fetal age, how far along you are in your pregnancy, and other pregnancy-related data.
Article Source: www.articlealley.com