On an average, the baby takes about 40 weeks to develop completely, and your due date is calculated from the first day of your last menstrual period. If you have a regular menstrual cycle of 28 days,
then fertilization would have taken place on the 14th day of the cycle and not on the first day of your pregnancy; as ovulation takes place 14 days before your period begins.
So, technically speaking, during the first week of your pregnancy, you weren’t actually pregnant. You were only having your last period. In the second week, your body initiates and completes the ovulation process, which is characterized by the production and release of an egg from the ovary. As soon as the egg is released, if it is fertilized by a sperm, and you become pregnant.
Once conception has taken place, the baby takes approximately 266 days to grow and develop fully. However, it is exceedingly difficult to pinpoint precisely the moment when the fertilization took place. For this reason, the due date, also referred to as the Estimated Date of Delivery (EDD) or Estimated Date of Confinement (EDC), is calculated from the first day of your last menstrual period, and not the day of conception.
To calculate EDD, get hold of a calendar and start counting. Suppose, the first day of your last menstrual period was 10th April:
- Count one year forward that will be 10th April of next year
- Count three months backward, which will be 10th January
- Add 7 more days and your EDD will be 17th January
If your menstrual cycle is longer than 28 days, then don’t forget to add the extra days. If it is shorter than 28 days, then subtract the requisite number of days to get the correct EDC.
No matter how much you calculate, your EDD will always remain an approximation. Your baby can arrive a couple of weeks before or after your due date, and still be on time. Unless you plan a caesarean
section, you cannot foretell on which day your baby will be born.