How Long is Pregnancy?

One of the strangest and most problematic aspects of pregnancy is trying to determine exactly how long a woman has, in fact, been pregnant.

In my limited experience, there are three calculations:

• When determining “how far along” you are for medical check ups, you’re basically on a 40 week schedule which starts around the last menstrual cycle prior to the pregnancy. But if that’s before the pregnancy starts, how can that be the starting point? I never realized a due date is determined from that date which has no direct relationship to conception.
• The generally held standard, at least as I understood it, was that pregnancy lasted 9 months. If there are 52 weeks in a year and nine months is three-fourths of a year, this calculation would mean that a pregnancy would last 39 weeks (I’m good at that math stuff).
• If you’re measuring from conception, that’s a trickier since it’s not always entirely clear what the start point is. Based on my rudimentary knowledge of ovulation, I’m under the impression that the “best” time is approximately halfway through a standard 28 day cycle (and yes, I feel as awkward writing about this topic as you’re probably getting by reading it) which would cut two weeks from the 40 week schedule in the first calculation. Said another way, 38 weeks.

So there you have it, three calculations, all with different answers. The one thing I’ve heard people say is that pregnancy is ten months. I think it’s clear that that is not the case. A month has more than four weeks, so unless you’re pregnant in some weird year that inexplicably has ten straight Februarys, the standard gestational period is less than ten months. Case closed on that calculation, which is why it didn't get its own bullet point.

Since months have inconsistent numbers of days, the generic “nine month” calculation is utterly useless and really should just be stricken from the lexicon of pregnancy. And to be honest, since Lindsay has been pregnant, I’ve never thought of her as “x” months pregnant. Though she has recently started making reference to the "fact" that she'll be "8 months pregnant" at 32 weeks, which is next Friday. I've tried to argue that fact but the only thing it causes is confusion.

Other than the looming "8 month mark," we speak in weeks (even though, until recently I have to admit that I got confused as to how many weeks along she was – I’m not a total stereotype though as I’ve always remembered the due date, which is February 22 – it’s possible I’ve remembered that just because 2/22 is easy, perhaps even easier than our wedding anniversary, October 4 – ten-four, good buddy).

However, if you measure in weeks, it makes trying to identify the start and end point of a trimester difficult, given neither 40 nor 38 are divisible by three. It also would seem strange, if you use the forty week measure, to start your first trimester two weeks before you’re even pregnant. Using that logic, every woman without child is technically pregnant two weeks out of every month of her entire life.

While there’s really no milestone that marks the start or end of a trimester, it just seems like other than the first is when you’re supposed to be sick, the second is when you’re supposed to glow, and the third is when you basically want nothing more than to just have the child.

At the end of the day, I guess it really doesn't matter - so what if it causes confusion as to what "month" your wife is trying to complete in her pregnancy journal and you secretly wishing it just said, "weeks 29 - 32" to alleviate that confusion. The goal is to keep the little bugger in the oven for as long as possible, even if your wife isn't sure which "month" to be filling in the pregnancy journal.