Pregnancy Over 40, Due Date CalculationI remember getting two different due dates from two different healthcare providers when I was pregnant. The problem is that there are so many variables which determine when a baby will be born. I think back to my mother's generation...there were no ultrasounds and the due dates were frequently estimated. Many women didn't even know they were having twins until they delivered! This article addresses why it is difficult to pinpoint an exact date:
SEE ALSO: getpregnantover40.com FOR MORE ARTICLES ON GETTING PREGNANT AND STAYING PREGNANT OVER THE AGE OF 40For earlier generations of women, the concept of a due date was “around Thanksgiving” or “late fall.” As birth moved from home to hospital, women were given the approximate date when they should expect to be confined to a hospital bed, called the “estimated date of confinement.” Eventually, this term evolved into “expected date of delivery,” now called “due date.”
Unfortunately, a specified due date has made women (and their family and friends) place too much emphasis on a precise day - to the point that they plan their life around it. Your baby doesn’t have a calendar, however, so it is no surprise that less than 10 percent of babies actually arrive on the date they are due. For the other 90 percent of pregnant women, what does your due date really mean?
The Numbers Game
Many health-care providers use a sonogram to pinpoint your due date, but don’t be swayed by technology: A date based on an ultrasound can be off by a week or more depending on the skill of the technician, the timing of the sonogram and the size of the baby. Until 13 weeks of gestation, most babies grow at the same rate, but as pregnancy progresses, fetal size corresponds less and less to the amount of time that the baby is in the womb. So while many health-care providers keep giving ultrasounds to reassess a woman’s due date throughout her pregnancy, the date is actually becoming less accurate as time goes by. In fact, there’s really no need for a sonogram to determine a due date unless you don’t know the date of your last period.
If you do know the date of your last period, try the following calculation, called Naegele’s Rule. Babies have a gestational period of about 280 days, so count back 3 months from the first day of your last period and add 7 more days. Your approximate due date is that day within the next year. Take note of the word “approximate:” Your baby will grow and mature on his own schedule. The only thing you’ll know for sure is that you should give birth within two weeks before or after that day.