Calculating your due date is never a precise science. Unless you can pin point the exact date and time of your conception, you’ll not get an exact date of delivery. Even then, don’t expect your baby to arrive on the appointed date. He or she may decide to come early or a bit later. However, you do need to have some idea when to expect labour, so you can prepare.
Why is it important to calculate your due date?
When you see your midwife for your first antenatal check-up, she’ll calculate your due date. Your due date will not only help her schedule future appointments, but it is important in monitoring your baby’s development. At every stages of your pregnancy, your unborn baby is expected to reach milestones. For example, at five weeks, your baby’s heart should start to beat. Without knowing your due date, medical professionals will not know whether your baby is progressing as expected.
Your midwife will also schedule a dating scan to confirm your due date. Although a dating scan is more accurate than the traditional method of working out due dates, it’s still not completely accurate.
How to calculate your due date
There are lots of online parenting sites that offer a due date calculator. But if you prefer to calculate it yourself, you will be happy to know, it isn’t that difficult. To work out your due date, you can use the following formula: Estimated Date of Delivery = Date your last period started – 3 Months + 7 Days.
The formula is referred to as the Naegele’s Rule. It’s named after Dr. Franz Naegele who devised it. It’s a method traditionally used by midwives. And it’s the same formula used in online calculators. However, the assumptions in the formula are problematic assumptions. For example, it assumes that you have a twenty-eight day cycle, that you ovulated on the fourteenth day of your cycle, and that each month has equal days. As we all know, every woman is different! And so are babies, some will be in a hurry to arrive, some will be punctual and some will invariably be late! Still, using the formula gives you a rough date on when to expect your baby.