The first question every woman asks when the doctor confirms that she is pregnant is ‘when is my baby due?’ Most doctors have a colorful wheel, or a calculator, which counts 266 days from the moment of conception, or 280 days from your last period. Other doctors will honestly tell you that this calculation is only an estimate, and that only baby knows for sure. Two weeks plus or minus the calculated due date is considered normal. And there are many other things that can change this calculation.<\/p>\n
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The calculation for the baby due date came to us from Dr. Naegele, a German obstetrician from Heidelberg. In 1850 he determined that the length of normal human gestation is 266 days from the moment of conception. His assumption was that an average woman has a 28 days long menstrual cycle and that all women ovulate on the 14th<\/sup> day of their cycle. So, his calculation for the baby due date was to take the date of last period, add seven days and deduct three months. The result is your due date.<\/p>\n We learned since that many Dr. Naegele”s assumptions were wrong. One of them is that not every woman ovulates on the 14th<\/sup> day of their cycle. The cycle length varies greatly from woman to woman. Different ethnic groups have different gestation length<\/a>. Scientists found<\/a> that white women, women aged 19 to 34 and women going through first pregnancy have longer gestation time from black women, women younger than 19 and older than 34 and women that already went through birth. Another study<\/a> also shows that African and Asian women have shorter gestation time than Caucasian women.<\/p>\n Many other things changed since Dr. Naegele”s time to affect the length of our gestation: our prenatal care and nutrition are much better now, making pregnancy last longer.<\/p>\n The new knowledge about what affects our gestation length helps doctors to calculate our due date more precisely. Actually, more precisely than two weeks plus or minus. At the beginning of the pregnancy, a few days difference does not look like much. But, as the pregnancy progresses<\/a>, you can”t wait to get it over with and have your baby in your hands. On the more serious side, there are times when the exact date is very important ” \u201c when the birth has to be induced because of baby”s or mother”s health.<\/p>\nWhy should we care?<\/h2>\n