You're pregnant! Now one of the first things you'll want to know is how long ago did this happen and when will the baby be due? Due dates are not quite an exact science, as many children are born one to two weeks before and after their expected due dates. However, some babies may have impeccable timing. If you're adopting an infant from its birth mother, a due date is obviously going to be very important. However, unless she has been keeping a close watch on her menstrual cycles, it may be difficult to predict her due date.
In order to adequately calculate a due date, a woman will need to know the first day of her last menstrual cycle before the pregnancy. This date is actually the start of a woman's first trimester. Conception is likely to take place two weeks after that date, however, this date can be affected by the average length of a woman's menstrual cycles.
Depending on the kind of pregnancy calculator you go to, you may see slight differences in due date results and predictions of how long you've been pregnant, sometimes called the gestational age by some calculators.
You don't have to be pregnant to find use in a pregnancy calculator. Some calculators can help a woman predict when her 10-day fertility window will fall in the future.
Pregnancy calculators aren't necessarily going to be the most accurate way to learn about your pregnancy, nor will multiple calculators give you the same result.