Population decline

[salamandraugr]

Setting: Secondary world technologically equivalent to the early 19th century.
Search terms: no new births, declining birth rate, sub-replacement fertility, historical pregnancy per capita, historical birth rate

Comments

[lilacsigil]

Some of it's going to depend on other factors. You could roughly estimate maybe 15-20% of a pre-modern population are women of childbearing age (many children, few old people) but an immigrant population is probably going to have a larger number of people who were older children and young adults at time of immigration and who are able to travel, so skew that a bit higher to say 25%. Of all women, there's a steady number of about 12.5% (up to 30% in certain times and places) who never have children, so let's knock that back to 15-20%.

Of these women, you could have up to 50% pregnant at any given time (one pregnancy a year), depending on lifestyle, diet, breastfeeding practices etc. Women with less food and/or longer breastfeeding times are going to have children less frequently, and if there's a major female religious tradition involving celibacy, or later marriage, that will affect the numbers too.

Let's say the women have sufficient food, no reliable contraception, sufficient available men and tend to breastfeed their own children. That would mean a maximum of about 2400 pregnant women at any given time out of your population of 32000.

ETA: I don't think one year without children born is going to have much of an effect on your population overall, but remember than most of those women who die will leave behind children and someone will have to care for them. Kinship care systems will be well-developed but that's a massive strain all in one hit.

[naath]

I think the reduced number of women is likely to have more effect than one year with no babies.

The first world war killed roughly 2% of the British population and had a significant effect on the ability of women to find husbands in the years following.

If 10% of your population are pregnant at the time of the event and 1-in-5 of them die that's 2% of your population dead (2400 is a bit less than 10%). Worth considering that if all the men have gone orf to fight a war then they aren't at home getting their wives pregnant.

I would expect that most of the war dead would be male; so the problem of a gender imbalance might be reduced.

Having this event happen may make women more worried about pregnancy than before (although pregnancy is already pretty worrying if you don't have good health care) - is it possible it will happen again? Although reliable contraception is unlikely to exist *unreliable* contraception probably does, and is widely known about, possibly disapproved of but likely used; abstinence of course does work... will a year of no babies lead women to try harder to have babies, or to try harder to avoid babies?

[salamandraugr]

I like those numbers. 2400 women losing their babies and over 400 of them dying in a single night would be enough to scare the rest of the city, even those of other ethnic groups. Word of mouth and yellow journalism would make things seem significantly worse.