This is a mystery I never quite fathomed until I became pregnant. Pregnancy is measured by weeks: 40 weeks total. For you smarties out there, yes, that is TEN months, not nine. There is your first pregnancy myth.

It is also measured in three trimesters. Each trimester has its own milestones and symptoms. A trimester “should” be a group of 12 weeks.  However, because 3x12 is 36, not 40 where do the extra 4 weeks factor in?

Well, here is some fertility science for you. Because not every woman ovulates at the same point in their cycle, doctors calculate pregnancy from the first day of your last menstrual period (LMP). That means by the time you get a positive test, you are usually 4-5 weeks along. Therefore, you get extra credit for being pregnant before you even ovulate!

So, as of April 1, 2007, I am 25 weeks pregnant. That is the third week of the sixth month. In two weeks, I will be in my third trimester. We have a little over three months to go. I can hardly believe it myself.