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Reconsidering Childbirth and Survival Tables


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Morien has posted on this topic before suggesting the changing the childbirth tables so they were less deadly to mothers, and his thread got a lot of replies and some alternative approaches (CON saves). For my own reasons I was inspired to research medieval maternal mortality, fertility, life expectancy, etc. and after digging into it all, while I liked Morien's original solution best of what was suggested, but as he wrote, those changes still didn't go far enough and remained too deadly. I decided to bite the bullet and make some house rules with proper tables. I tried to keep close to core rules and the corrections found in the Book of Estate. I also wanted to minimize rolls and bookkeeping. I'm pleased with the result and decided to share it with you all.

 

The 1 page house rules & errata are attached. Below is some discussion on the issues addressed and then footnotes for my research. I am sure most people couldn't care less about so much detail, but I provide for those who might. I had fun with this exercise. Enjoy!

 

(Hopefully 6e has already fixed these issues.)

*****

Issue 1, Maternal Mortality Rate (MMR):

* The Core rules have an MMR per pregnancy of 20%!

* Research: medieval aristocrats historically experienced a MMR around 1%.[1][2]

* These house rules generate an MMR of 1.5%.

 

Issue 2, Fertility with Age and Income

* The Core rules use a fixed 45% per annum fertility rate. Greg's web page introduced the concept of reduced fertility rates with age, but these were never published and retain the high MMR.

* Research: 16C English women aged 20-25 experienced a 43% fertility rate declining with age.[3] British peers with wives married before age 25 experienced a 42% fertility rate in the first 5 years of marriage from the mid-16C to mid-19C.[4] Modern medicine tells us male fertility decreases rates with age, roughly halving in their 40s.[5]

* These house rules start with a 44% fertility rate for women under 25 and adjust them down with age consistent with the biological rate of decreasing fecundity. This adjustment is necessary if we reduce MMR, otherwise unreasonably large lifetime progeny per mother results. Reduced fertility for men is also added for completeness. The house rules also remove most effects of income on fertility as that just isn’t supported empirically – nobles didn’t have larger families than the population average. Impoverished knights are however required to take a year off of childbirth rolls if a child is born. (Nobility achieved short intervals of childbirth by employing wetnurses; presumably an impoverished knight has better things to use his limited money on.)

 

Issue 3, Infertility

* The Core rules are silent on infertility, while Greg's web page tables include it.

* Research: while I could not quantify medieval infertility rates, childlessness was an issue for a material percentage (18% in one sample) of medieval aristocratic marriages[2] and it is a central issue in the tragedy of Arthurian lore. The modern rate of primary infertility is around 2% and secondary infertility increases with age to about 20% by age 40.[6]

* Is this a game-worthy issue? I went back and forth myself and decided ultimately to include it in the house rules. It is easy enough to ignore it if you prefer (don't make the primary infertility roll and ignore the infertility complication), but if your table is OK with it in the game, it is a potential source of drama. The house rules have a 2.5% primary infertility rate and the tables add secondary infertility reaching 20% or lower at age 40 (depending on age of first roll on the tables.) Male fertility declines are also included in a simple manner to reduce conception chances without increasing chances of complications.

 

Issue 4, Twinning

* The Core rules have a twinning rate of over 11% of pregnancies!

* Research: Identical twinning is biologically constant at ~0.4% of pregnancies, and the fraternal twinning varies from under 1% to over 4% depending on age, parity, race, etc.[7][8]

* These house rules use a fixed twinning rate of 2%, with identical twinning at 0.5% and a 1.5% rate of fraternal twinning chosen as a reasonable estimate for the setting given the high parity implicit in the childbirth tables.

 

Issue 5, Sex Ratio

* The Core rules have an even sex ratio between males and females.

* The observed medieval sex ratio was 110-115:100 males to females.[9]

* These house rules have a sex ratio of 110.7. The sex ratio and twinning get fixed together in one change so I couldn't resist implementing it even though it is a minor issue.

 

Issue 6, Infant & Child Mortality

* The Core rules have an unrealistically high child mortality rate of 80%! The Book of Estate fixes this and reduces it 30%.

* These house rules achieve the same 30% child mortality, but resolves all the mortality by age 6. Demographically we know over 85% of childhood deaths in low life expectancy populations occur in the first five years of life.[10] It strikes me as both a better simulation and playability benefit to cut out some rolls to simplify this.

 

Issue 7, NPC Life Expectancy

* The Core rules have no provision for NPC death from age 15 on (MMR being the exception.) The Book of Estate fixes this and removes immortal NPCs with annual survival checks. NPCs have a life expectancy at birth, E(0), of 35 years and at age 20, E(20), of 27.

*  Honestly, the Book of Estate tables are fine, but since I was already making my own table for children, I included adult NPCs as well. Arguably the E(0) is too low for rural nobility, but I left the house rules have very similar outcomes, E(0)=34 and E(20)=28, but they have a slightly more realistic "shape" to the mortality pattern by having lower mid-life mortality followed by accelerating mortality with age. They also provide for a higher mortality rate (and lower E(0)) for poor individuals, an adjustment that is lacking in the Book of Estate but was included in the Core rules.

 

Notes:

[1] Lewis, J. (1998). “'Tis a Misfortune to Be a Great Ladie”: Maternal Mortality in the British Aristocracy, 1558-1959. Journal of British Studies, 37(1), 26–53.

[2] Podd, R. (2020). Reconsidering Maternal Mortality in Medieval England: Aristocratic Englishwomen, c. 1236–1503. Continuity and Change, 35(2), 115-137.

[3] Flinn, M. W. (1981). The European Demographic System: 1500–1820. Baltimore: Johns Hopkins University Press, quoted in Clark, G. (2007). A Farewell to Alms: A Brief Economic History of the World. Princeton and Oxford: Princeton University Press.

[4] Hollingsworth, T.H. (1965) The Demographic Background of the Peerage, 1603-1938. The Eugenics Review 57(2), 56-66.

[5] Harris, I. D., et. al. (2011). Fertility and the aging male. Reviews in Urology, 13(4), 184–190.

[6] Mascarenhas M.N., et. al. (2012) National, Regional, and Global Trends in Infertility Prevalence Since 1990: A Systematic Analysis of 277 Health Surveys. PLoS Med 9(12): e1001356. https://doi.org/10.1371/journal.pmed.1001356

[7] Bulmer M.G. (1970). The Biology of Twinning in Man. London, U.K.: Oxford University Press.

[8] D'Addato A.V. et. al. (). Trends in the Frequency of Twin Births over the last Century: European Comparisons. Unpublished draft from 2004 & 2006 articles by the authors.

https://epc2006.princeton.edu/papers/60568

[9] Bardsley, S. (2014). Missing Women: Sex Ratios in England, 1000–1500. Journal of British Studies, 53(2), 273–309.

[10] United Nations (1982). Model life tables for developing countries. Population Studies, vol. 77. New York.

 

Childbirth and Family Events House Rules.pdf

Edited by vegas
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One more resource for you and I'm done with this topic. Rolling every year for every NPC is a pain and I imagine most refs ignore it. Rather than slavishly following that method RAW for adult NPCs, we could instead just use a life table and roll once to look up year of death. That way you are only making one roll for each NPC rather than rolling for all NPCs every year.

To do that I took the UN life tables for a 35 year life expectancy and built a d100 Survival table in five year periods. (Could have done annual periods, but the table just gets really large and this is more than good enough for gaming purposes.) The instructions are on the attached table, though a ref could be creative and use it differently. Personally, as the note in the instructions suggests, I'd use the table as is for commoners and give nobles a bonus 5 years of lifetime.

Survival Table Alternative Age of Death lookup.pdf

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Pretty neat. The Survival Table in particular can be very useful, getting rid of the yearly rolls for the NPCs.

I have my own Family Events system where I roll just once for the death in the family (that is, unrelated to everything else going on), which has the downside that only one 'accidental' death may occur any given year. On the other hand, we have had people die in duels, wars, etc. as well, so it is not so bad, and keeps me sane.

The Book of the Estate Family Survival system does include the standard of living modifiers for the kids, but only on the second roll (see p. 14). It would be easy enough to extend that to the adults, too.

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@Tizun

  • After the 5 first years, do you still roll on the survival table? After all, the NPC adults must roll.

For these house rules, you have to stop rolling at age 6, otherwise too many children would die. The target is 30% child mortality (that is both roughly historically accurate and matches the BoEstate) and these rules achieve that level in the 6 rolls, newborn to five, rather than 21 rolls.

Why do it this way? First it is more accurate (though imperfect) because 85% of childhood deaths do happen that early and they are not spread out evenly every year from age 1-20 as BoEstate has it. Second I am sensitive to how many rolls the game asks us to make for NPCs and I am looking to cut down on bookkeeping and rolls where I can.

But maybe you want to keep your players more stressed and not know that a child will reach maturity if they reach age 6? If that is the case, here is how to have your cake and eat it too: keep the house rule table, but if the child dies on roll in their 5th year, roll one more d20: and that is their age at death. (a 1-5 result all mean age 5.) You get the benefit of making fewer rolls, and your players don't know if they child will survive or not until they are 21.

  • Do you use the standard of living modifiers? Except for extreme poverty, it seems not.

I do not. A lot of work/thought went into that decision, but here is a quick summary. First (and Morien made this point) even an impoverished knight has a lot of money compared to a commoner so standard of living is highly relative. Second there is very little historical evidence that wealth had any effect on childbearing or life expectancy. Whether we look at ancient or medieval evidence, aristocrats tended to have the same or smaller families than commoners and aristocrats had the same life expectancy as lower classes.

Now if you dig into the historical evidence, its a bit more complicated than it seems on the surface, more complicated than I want to (or probably could) model in some game tables. So I default to a simple but good enough answer: above 3 Librum in household income and you get a survival bonus. But do note, our family NPCs are also facing a high chance of death from the family events table; 10% of the time, someone dies each year. The bonus on the Survival table is intended to roughly balance the risk faced on the Family Events table keeping commoners and nobles with roughly the same life expectancy on net. Impoverished knights, alas, get the worst of both worlds.

@Morien

Thanks for the heads up on BoE. I will have to re-read that section because clearly I missed that.

And while I have your attention, Morien, let me just write a thank you for all the resources you have posted: the thread on childbirth, your house rules, your suggestions for supplements. I am a Pendragon noob and I found your posts enormously helpful in getting up to speed efficiently on the game and the rough edges to think about. Thank You!

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34 minutes ago, Voord 99 said:

These are really good.

The only addition I can think of is that one might mention the possibility of some unmarried NPCs in the family who are monks, nuns, and (depending on when you’re drawing on for your version of the Church(es)) priests.

Thanks Voord! That is an excellent point and in fact I do assume the heir, spare, prayer roles for the first three kids of NPC families and I should update the rules to reflect that. Great point!

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23 minutes ago, vegas said:

Why do it this way? First it is more accurate (though imperfect) because 85% of childhood deaths do happen that early and they are not spread out evenly every year from age 1-20 as BoEstate has it. Second I am sensitive to how many rolls the game asks us to make for NPCs and I am looking to cut down on bookkeeping and rolls where I can.

1st: Yeah, BotE has a flat distribution from 2 to 21, with a high (10% mortality) peak for infants (i.e. the first year). I think we had a 1-5 column in one of the drafts, but since we didn't want to be constantly changing the second roll (which is a simple 1-5 or 1-10), we couldn't really make that work and simplified it to 1-5 throughout to get that 30% total mortality in the end.

2nd: Yeah, I am totally with you on that. Especially if you are trying to stick to the 1 session = 1 year, rolling loads of 1d20s for the NPCs is way too much. That's why the lifespan table is a very nice addition. 🙂 I don't think I adopt it for our campaign, as the relatives have been dropping dead often enough as it is from the system I already have in place, but I'd definitely consider it otherwise.

29 minutes ago, vegas said:

And while I have your attention, Morien, let me just write a thank you for all the resources you have posted: the thread on childbirth, your house rules, your suggestions for supplements. I am a Pendragon noob and I found your posts enormously helpful in getting up to speed efficiently on the game and the rough edges to think about. Thank You!

Thank you, very kind of you to say. Glad that they have been helpful; that is what they are there for, and do feel free to ask any questions either here or in Discord; if it is a quick rule question or some such, Discord is fine, but Forum is better for longer discussions. 🙂

I started my own Pendragon GMing career back in late 1990s, armed with 4th edition rulebook, The Boy King, and Warren Mockett's campaign outline that covered 503 - 510s (I want to say 515, but I am not sure anymore; alas, I have lost the file and the printout got thrown out half a dozen moves ago). That campaign outline was very helpful to me as a new KAP GM, so contributing by advising new KAP GMs is a way to pay it forward. Not to mention I very much like talking about Pendragon, as is no doubt obvious by now. 🙂

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30 minutes ago, vegas said:

I do assume the heir, spare, prayer roles for the first three kids of NPC families

Emphasis on NPC families. Things of course varied.

It can be a pretty interesting background for a PK, too.

An example of Gilbert Marshal, the 3rd son of the famous William Marshal: https://en.wikipedia.org/wiki/Gilbert_Marshal,_4th_Earl_of_Pembroke

Gilbert was probably on a clerical career, when the death of his older brother Richard meant that he was now the heir to the earldom of Pembroke. He was knighted and then given the title.

Gilbert's younger brothers, Walter and Ansel, were both raised to be knights and had been left with lands in their father's will.

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4 hours ago, vegas said:

@Morien

And while I have your attention, Morien, let me just write a thank you for all the resources you have posted: the thread on childbirth, your house rules, your suggestions for supplements. I am a Pendragon noob and I found your posts enormously helpful in getting up to speed efficiently on the game and the rough edges to think about. Thank You!

Here Here!!

I'm certainly not a Pendragon noob - been running it for over a decade - but Morien's ideas and thoughts are almost always ones I find myself stealing for my own campaign.

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@vegas, in the second paragraph of the Childbirth section of the first document, there's the following line:

Quote

Prior to a woman is making the first childbirth check in her lifetime, roll 2d20 and a 5 or less indicates “mother infertile”.

I'm not sure how to parse the beginning of the sentence.

ROLAND VOLZ

Running: nothing | Playing: Battletech Hero, CoC 7th Edition, Blades in the Dark | Planning: D&D 5E Home Game, Operation: Sprechenhaltestelle, HeroQuest 1E Sartarite Campaign

D&D is an elf from Tolkien, a barbarian from Howard, and a mage from Vance fighting monsters from Lovecraft in a room that looks like it might have been designed by Wells and Giger. - TiaNadiezja

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@AlHazred,

Sorry, the sentence got garbled in revisions. I'll edit it. (hint: remove the first "is").

The idea is a woman character rolls one time in her life to check for fertility, and if she succeeds at that "saving throw" by rolling 6 or higher on 2d20, then she is fertile and proceeds to roll on the childbirth tables normally (at least until she gets a "mother infertile" as a complication).

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59 minutes ago, The Wanderer said:

How do you manage the "programmed death" of the NPCs? I'm asking because I don't want my players to know when their relatives are going to die, of course! Do you make secret rolls?

I'd roll in secret and make a note for myself when each of them is supposed to die, if nothing else happens. Sort by death year (in Excel or Google Sheets) and hey presto, you have an easy checklist year by year.

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