Your baby's birth date is the first of many things that you can't control in your child's life. Still, if you have your heart set on a spring baby or a Christmas miracle, you can certainly try to use a little bit of math to help make your dream come true. While a due date is just an estimate, you'll have the best chance at hitting your mark if you do a little up-front planning.
Chart your current fertility cycle. Hitting a specific due date is very difficult, but your body may be on your side. Begin marking your calendar to track the first day of your period. You can try to get pregnant within a given cycle, but getting pregnant on a specific day is entirely up to you body.
Understand how due dates are typically calculated. Generally speaking, a due date is calculated by figuring the first day of the woman's last menstrual cycle and adding 280 days (or 40 weeks).
Choose the date you want. Let's say you'd really like to ring in the new year with a new baby. Your ideal day would then be Dec. 31, 2011.
Subtract 280 days (or count back 40 weeks) from your desired due date. This will give you the date that would, ideally, be the first day of the menstrual cycle in which you get pregnant. If you want a due date of Dec. 31, 2011, the first day of your menstrual cycle should be March 26, 2011.
Compare that date to your typical cycle. The dates may not match up. If you have been charting and realize that your cycles generally start around the 10th of the month, it looks like your dreams for a New Year's Eve baby are going to go unfulfilled.