Pregnancy rate

[Glacialis]

I'm trying to figure out pregnancy rate for fantasy worlds. Specifically a post-apocalyptic evil-god-has-come rare-magic world but I'll take standard D&D/FR, too.

1% of women at any given time? 0.5%? 0.5% only if the community is going well? etc

Googling for this brings up so much politics I spent twenty minutes sorting through it. My aching head...

 

[XCorvis]

You'd probably be better off hand-waving it or just choosing a value that gives a good result. What is it you are actually trying to figure out?

 

[Glacialis]

How many people need to die horribly in order to prevent a good prophecy from coming true. How many would be overkill if they're associated with a given PC. It's only a town of 1,000, so I'm going for an unusually high number of pregnancies due to both prophecy and an unusually productive town. With unusually lenient overseers...for now. Say, a dozen. Three of which are of interest to the party so far.

Sucks to be in a world where the bad guys have already won.

 

[MavrickWeirdo]

Supply and demand.

Typical population with typical crops output has typical number of pregnancies (let's say 8% of women)

Typical pop + typical crops = 8%
Typical pop + below average crops = 4%
Typical pop + above average crops = 16%

Reduced pop + typical crops = 16%
Reduced pop + below average crops = 8%
Reduced pop + above average crops = 32%

Increased pop + typical crops = 4%
Increased pop + below average crops = 2%
Increased pop + above average crops = 8%

If for example the harvest was unusually good, but then after the harvest alot of the men were pressed into the army (10%), then I would expect a baby boom where as many as 1/3 of the women in town got pregnant.

 

[Glacialis]

That's...a lot of babies. Will ponder.

 

[ceratitis]

That's...a lot of babies. Will ponder.

you YOU baby killer you !!!!


would you like some pregnancy magic spells?
Z

 

[Dr. Strangemonkey]

Historically, agricultural societies with stressed food supplies have the highest rate of pregnancy. Surpluses of food actually tend, on the whole, to reduce the number of children per family.

Religion plays a significant role, but the highest correllary is the level of education valued in women. Which actually translates into the Malthusian principle that delaying marriage is the best control on population.

For a small community, however, I think most of this would go out the window. The only base criteria I would use are the anthropological standards:

agricultural=one child every two years for most nubile women

hunter-gatherer=one child every four years for most nubile women

I don't know what the rate is for pastoralists, but I would assume it's less than that of agriculturalists. So figure out what the number of nubile women is in the community, if there are any customs, environmental, or demographic abnormalities skewing the figures, and then work it out with the ratios.

 

[XCorvis]

How many people need to die horribly in order to prevent a good prophecy from coming true. How many would be overkill if they're associated with a given PC. It's only a town of 1,000, so I'm going for an unusually high number of pregnancies due to both prophecy and an unusually productive town. With unusually lenient overseers...for now. Say, a dozen. Three of which are of interest to the party so far.

Sucks to be in a world where the bad guys have already won.

Does the number actually matter? Call it "maybe a dozen" or "dozens" or "all the babies in the entire town".

If the PCs are investigating each one, make the number manageable. Say, 24 babies but 20 of them are obviously not the one, so checking each of them out isn't so hard. Even so, it doesn't really matter how many there are, it only matters how many of them would be of interest.

 

[Rabelais]

In his article Natural Fertility and Family Limitation in Roman Marriage, Bruce Frier discusses the attempt to link modern statistical analysis of rates of fertility in several contemporary and near-contemporary cultures to that of expected fertility rates in Roman Egypt. Frier, using modern statistical modeling, strenuously refutes the argument by John Riddle that Roman families actively limited the size of their families through the use of contraceptives and abortion.

Frier also suggests that the understanding of the female reproductive anatomy was extremely primitive, making successful fertility interruption unlikely at best, and at worst potentially deadly.

Furthermore, Bruce Frier strenuously argues that to even attempt to do so, considering the enormous burden of infant mortality would be cultural suicide, reducing birth rates to the point that population stability would be impossible. Frier leaves open the argument that non-marital fertility rates (prostitution, concubinage etc.) would be open to limitation by contraception or abortion.

Bruce Frier uses analysis conducted by the French demographer Louis Henry. Henry believes that rates of fertility, and expected rates of fertility can be divided between cultures that are Pre-transitional and Post-Transitional. Pre-transitional cultures practice no effective limitation to fertility either through contraception or abortion, nor is there any conscious “family planning” through normal life

Age.........................................Expected Fertility Rates
12-14.....................................................225
15-19.....................................................420
20-24.....................................................460
25-29.....................................................431
30-34.....................................................396
35-39.....................................................321
40-44.......................................................67
45-49.......................................................24


There’s more if you really want it. Drop me an email at Rabelais@comcast.net and I can send you what I have on natural fertility among pretransitional cultures.

 

[Rabelais]

I'm not actually that bad of a writer... I sliced the heck out of a short paper I wrote for my Roman Daily Life class. I have a PDF of the document if you want it.