I am not sure women actually gave 10 births on average. The probability of conception during a single period hardly exceeds 20% and often is less. Also, women can't conceive during pregnancy and for some time after that. And there are some complications during pregnancies.

The answer may as well reside in how much you want child mortality rate be a theme in your novel. A lot of things happened in pre-Industrial Revolution times that are different from our modern times; and more still that would clash with our perception of life. Realism is good and all, but you can't possibly hope to talk about everything while moving the plot along. How much is this theme relevant to you and to the novel?

@rus9384 Queen Victoria had 9 children. Catherine of Aragon gave birth 7 times (only one child survived). I'm too lazy to look for historic examples I don't remember off the top of my head (especially considering many times still births were not recorded), but both my grandparents had ~10 uncles on each side (before the Holocaust, that is). Evidence seems to be pointing towards ~10 births. You're forgetting women got married very young, and noblewomen in particular had wet-nurses, so they could get pregnant before the older child was weaned.

@rus9384 10 is probably about right - birth rates in the pre-industrial era were much, much higher, than they are now. Even today there are countries with Fertility rates of over 7 (and that includes those who never have children)

@Liquid My MC is a king, so the main plot is all about war and politics and court intrigue. He inherits the throne young, and I explore long-term consequences of his decisions. Thing is, family ties in general, and the number and health of royal children in particular, tend to become rather important in this kind of story (historically).

According to studies the world population was around 650 million by the end of 17th century. By the end of 18th century it is around 1 billion. That means around 40% increase for about 4 generations. And around 9% increase per population. Which means that on average only 2.18 children per couple reached the middle of reproductive age.

The children of kings are always going to be more important than the children of everyone else. Even today, the media obsesses on the baby bump of the royal concubines. Updates and medical reports are leaked (or manufactured), and the management/care/legitimacy of royal children is the stuff revolutions are made of. In a major contrast, a very poor woman may face the need to terminate a newborn, knowing she cannot provide for it. Agrarian societies actually had a good idea how hard the coming winter would be based on the harvest. Mother's without healthcare often had to make a Sophie's choice.

@Galastel I'd add that to the question,to make it more answerable, then. The decision to write about it or not is still on you, but it's a pretty big detail, and it narrows down the scope for potential answerers.

@rus9384 Your statistics say how many children survived. My question is about all those children who didn't survive - the still births, the babies that died before age 1, or 5, or 10.

5 or 10 are not the babies already, of course. During those times lifetime expectancy was around 25-30 years. It takes into account lifetime of newborns. That means that on average there were much less births than you say. But who knows, maybe historicians are wrong? Yet, I'm pretty sure rich people were not bothered to use/practice contraception (I am not talking about condoms, of course), but poor people were.

@rus9384 In fact, we know that both contraceptives and abortifacients were used. Recipes survived. Which is also how we know they were about as efficient as the rest of medieval medicine - some worked sometimes, some didn't work at all, some had a chance of killing the user. I don't see how you get from life expectancy to number of children though. Life expectancy takes into account infant mortality, of course. There's at least one variable missing though.

@rus9384 Your stats are over such a long time period that the growth rate is effected by generational differences. Think about all the wars during that period which would mean many people, who survived to adulthood, never got a chance to reproduce. Your birth rate figure misses them. You cannot realistically infer birth rate from the population growth rate. The population growth rate gives you a minimum birth rate only.

Maybe read some of the conflicting historical research on this very question.

Not pre-industrial, but it's perhaps worth noting that in Ancient Rome child mortality was so regular that children that died under the age of one often didn't receive any formal mourning period. Bones of infants have been found in general household waste

@Ryan But isn't that covered by lifespan expectancy?

@rus9384 You're also lacking the other edge of the equation: the people who lived to reproduce, what age did they typically reach? Once they got over the dangers of childhood, did they usually live to see their 40th birthday? 50th? 60th? 70th?

@rus9384, key words: reached reproductive age. Child mortality throughout most of history was a mind-boggling 75% to 80%. Sure, a man who reached the age of 20 would probably live to see 70, and a woman who reached 45 would probably also live that long, but a newborn only had a 1 in 4 chance of seeing their 20th birthday.

@Mark Well, wikipedia states it takes into account any age and it has 24.5 (18th century) years in some countries. Well, if it takes into account only reproductive age. That's weird.

While in the developed world, this is indeed something a person can barely recover from, this is not so much the case in the developing world. As a Westerner living in Indonesia, I have plenty of friends in their thirties or late twenties, many of whom lost siblings. And while Western parents would absolutely be destroyed, here the parents find some way to process it. You may want to look at these cultures for some real-life examples of how this is done.

Well, however, the question of dying children can be actual even if I'm not wrong in this particular case. We can take prehistoric times and there it will be really common. Though, I guess even having an adult friend eaten by a beast was relatively common right there.

If you haven't read it already, check out the series Rashi's Daughters. It deals very well with this issue and strikes a good balance IMHO.