The first thing a woman wants to know when she thinks she is pregnant is if she is actually pregnant. The second thing she wants to know is her due date. Besides how the due date affects the pregnancy and trimesters, knowing the due date helps you plan out when your child's birthday will be: what month, what season, even what sign (if you are into astrology).
Your due date is usually not your baby's birthday
Every pregnant woman knows that when you are pregnant, the countdown to your due date begins the day of conception. But what is clear is that what you think is your due date may not be your baby's actual birthday.
There are 266 days from the day of conception to your "due date" or 280 days if you count from the first day of the last period.
The babyMed pregnancy calculator gives you a great way to calculate the days up or down.
But the what seems to be a simple question “When are you due?” is really not that simple. Only 5% of babies are actually born on their due date, and most are born before their due date.
The problem is that having been given a specified due date has made women place too much emphasis on a precise day.
Many doctors use several ways to calculate the due date including a sonogram, and the sonogram if done early before 20 weeks is usually precise within 7-10 days.
Many women (and their health-care providers) become so attached to their due date that when the baby doesn’t come on that day, they schedule an induction. But because the due date is unreliable in the first place, inducing the baby may cause him to be born too soon. These “near-term” infants (as they are known) can have trouble breathing, staying warm and breastfeeding, and they often need special hospital care after birth.
Induction isn’t without risks for you, either: Research has shown that a first-time mother whose labor is induced is twice as likely to have a cesarean as one whose labor starts on its own. When you let your baby choose his own birthday, it means he’s really ready to begin life outside the womb.
Your due date is an estimate of when you will give birth, not a guarantee. A much better way to calculate the "due date" would be to give you a range of days, maybe a 2-3 weeks period within which you would be expected to have the baby. You still should realize that about 10% of babies are born before 37 weeks, specifically if you are high risk or having multiples like twins.
Reverse Conception Calculator