Percentage of women pregnant

While at the mall today, Mrs. MC$E commented on the fact that there seemed to be a lot of pregnant women out today. It got me wondering, what percentage of women of child bearing age are pregnant at any given time. I can probably look up the numbers, but I’m not sure about how to go about figuring it properly.

I think I would need:

The number of women of child bearing age.
A definition of child bearing age (18-45?) or should I start younger?
The number of babies born per year.

I’m not sure about figuring the 9 months thing, if there are 100,000 babies born each year, do I count 75,000 pregnant-woman-years (for lack of a better term):confused:

Any ideas on how to figure this would be appreciated. Or just the answer if it’s already out there somewhere.

MC$E

According to this site http://www.census.gov/cgi-bin/ipc/popclockw

there will be 6,240,730,593 - 6,234,250,387 = 6,480,206
babies were born last month.
I think that means that 9 * 6,480,206 = 58,321,854
women or so are pregnant at a time.

Now we need to know how many women are there in the given range. I’d say 15-45 would be more realistic.

Neptune, your assumption is that the infants born in a month is equal to this month’s population minus last month’s population is incorrect. It does not take any deaths into account, including infant deaths. I think the number of births would be considerably higher than than your method suggests.

I also think 45 is too high an upper-end number. IIRC, only about 2% of women who try to get pregnant over age 40 succeed. So I’d put it at 35 or 40.

Another page from Neptune’s site says there were 5,042,426 births in the US in a 15 month period.

This census page says that the polulation of women in the United States, aged 15-39 (my estimate of childbearing years), on November 1, 2000 was approx. 48,662,000.

I believe I read somewhere, and I cannot find a site in support of it, that more than 95% of all women DO have a child at some point in their lives.

Well, the world birth rate is 22 live births per thousand population. Half those thousand are male, and a third of the females are well outside the range of age where pregnancy is likely, or even possible. That leaves 333 women to have those 22 babies. Half of all pregnancies do not result in live births, worldwide, so that means 44 pregnancies. Which means 13 percent of the women of childbearing age in the world are pregnant at some time during a typical year.

Tris

“You can tell whether a man is clever by his answers. You can tell whether a man is wise by his questions.” ~ Mahfouz Naguib ~

You don’t have to complicate matters by looking at total number of births in any given population. Just look at a steady-state poopulation, where every woman has to give birth to 2 children during her child-bearing years. By assuming that to be the age bracket 15-40, we have:
2 births * 9 months / (25 years * 12 months-per-year) = 6% pregnancy!

This off course assumes steady-state population, where all women achieve the ripe age of 45, which is maybe not a realistic set of assumptions.

On preview I see that Trisk claims that 50% of pregancies worldwide do not lead to birth. This does not necessarily double the ratio of pregnant women, as most of those pregnancies will not last for a full 9 months. I believe that the descrepancy between my 6% figure and his 6.5% (13/2) corresponds to the current increase of worldwide population.