As an expectant mother, the first thing you need to know is the expected due date (EDD) of the baby’s arrival. Pregnancy, once confirmed is a full 9months or 40 weeks long period during which the young fetus grows into a full-fledged baby. There are many ways of calculating a baby’s EDD. Here are a few methods:
It was a German obstetrician named Naegelle who first determined the method to calculate the average gestation period for humans. This method is still in use and is popularly called Naegelles’ rule.
Assuming that an average menstrual cycle lasts 28 days and the date of ovulation is 14th day of the cycle, Naegelle’s rule is:
EDD = (LMP date + 7 days) – 3 months
Where LMP is Last Missed Period
One other method is fetal heart tones measured through stethoscope and Doppler.
The first time you feel the movements of your baby is called quickening. This can happen anywhere between 18 and 24 weeks of your pregnancy. It is one of the factors used to determine the EDD of the baby.
Fundal height is the height of the fetus. The EDD can be calculated on based on the data obtained from measuring the fundal height at regular intervals during pregnancy.
The best pregnancy calculator is by monitoring the serum HCG levels in the body. This test is done using urine samples. The serum levels double every 2.5 days. Using this information, your physician uses an HCG graph to calculate the EDD more accurately.
Calculating EDD from LMP date can be erroneous as the ovulation can vary from cycle to cycle. Using certain charts and kits, your gynecologist can accurately determine your ovulation date.
A detailed sonogram conducted during the first month of pregnancy can determine exactly all the vital statistics of the developing fetus. These measurements and figures can help your sinologist to give you the EDD.
One should bear in mind that though the above mentioned methods help you in pointing at a date for your baby’s arrival, most babies arrive somewhere around the date and not necessarily on the same date. Many factors contribute to the birth of a baby and they cannot all be predicted on the first day.