So when will that baby of yours make the big debut? Unfortunately, calculating your pregnancy due date is an inexact science at best. Only five percent of pregnant women deliver ontheir due dates (which is why it's called an estimated due date), and any time within two weeks of that is considered perfectly normal (even it doesn't seem like it to you!) But still, having a pregnancy due date - even an imprecise one - is better than not having one at all. If nothing else, it gives you a date to circle (in pink? or blue?) on your calendar.
Since most pregnancies last approximately 40 weeks (or 38 weeks from conception), estimating a due date is based on the law of averages. The best way to estimate your due date is to assume your pregnancy will last 40 weeks (give or take a few weeks) from the first day of your last menstrual period. Better yet, use this Due Date Calendar instead (no need to do the math yourself!).
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