How can biological immortality lead to an increasing number of stillbirths?

Question

The society of an island nation is led by a religion known as "The Church of the Eternal Mother", it is an ancient faith that adheres to a fertility goddess. This faith is led by five elderly women called Mannas Natau, at least one of whom will regularly become spontaneously pregnant. These elders are biologically immortal and are worshipped as avatars of the Eternal Mother: mortal vessels of the goddess's power responsible for creating life and growing the numbers of the community. Children born from the goddess are immune to all illnesses and live longer than other humans, but are not immortal. The goal of the community is to ultimately build an empire by conquering its neighbors.

The elders have inherited a mutation in their biology which allows them their long lives. Cells during a normal life cycle multiply at a rapid rate, constantly dying and being replaced by new cells. This ability to proliferate doesn't happen indefinitely, decreasing as the individual gets older. Cells begin to produce errors in copying themselves, contributing to the person aging and eventually dying. The reason for the longevity of the elders is due to an immortal cell line, which evades normal cellular senescence and continually undergoes cell division. This ultimately gives the elders their immortality, allowing them to rapidly regenerate from wounds and protects them from natural illnesses. However, their is a natural downside to this. As they age, it becomes harder to produce live children. The amount of stillbirths increase as they get older, to the point where 90% of children are born dead.

What role could their natural longevity play in the creation of this problem?

Answer 1

Our gametes are not us.

Gametes are not genetically identical to the organism that produced them. They are the haploid products of meiosis, a shuffling of the parent genome and then only half the chromosomes.

The elders have some other things going on as well but a large part of their success is one gene and they need both copies of that gene to do what they do. Their descendants have 2 copies because the haploid oocyte duplicates itself in producing the spontaneous pregnancy. But while it is an oocyte it is haploid and it has only one copy. It is just an ordinary oocyte. It has none of the protection that every other cell in this body has. It ages.

---

Downvotes! I must unpack this further and maybe these can be tidied up.

1. Gametes age in these immortals because gametes are not immortal.

2. In normal women, age is correlated with increased rate of stillbirths. Older mother = more stillbirths. Maternal age and risk of stillbirth: a systematic review This is because the gametes age.

3. Normal women enter menopause before the rate gets to be 70%. These women do not enter menopause because all somatic tissues are immortal and self renewing. Their ova are not self renewing. As those age the rate of miscarriage goes up and up.

Ova age and with age comes accumulated mutation, and accumulated mutations are the cause of stillbirths in the real world and in this one.

Answer 2

Their immune system becomes better and better over time at recognizing foreign elements. Unfortunately, the babies are foreign elements.

The number of children they bear is also a factor, as in rh incompatibility syndrome.

Answer 3

The process you're describing is called Parthenogenesis. Unless there's something different about their physiology you're not explaining, their children would be their clones... but on to your question!

Eggs become less viable as they get older

There's a fascinating problem with your question: the number of eggs your Elders can carry will always be finite. Yes, you could create a rule that says they create eggs as they go and that process, like the process of creating sperm, can go on for as long as the body lives. But that's way to convenient.

Let's roll with what we know about terrestrial life: this means your Elders have a finite number of eggs, and that means that a time will come when they can't spontaneously become pregnant anymore. That can actually be an interesting issue with your religion.

But those eggs!

• If the mere mortals were paying enough attention, what they'd realize is that the pregnancies are quite regular. The genetics that caused immortality had a side effect: the eggs are released from the ovaries very, very, very slowly.

• But immortality isn't perfection. You don't say, but I'm going to assume that your Elders can become sick. Oh, they'll heal quickly just as their wounds will. But they're not gods. And since the eggs were all formed naturally from their births and matured to the point of viability at the same time... they're aging.

• As the eggs get older, they become less and less viable, resulting in an increasing rate of still births over time.

It's worth pointing out that your requirement that the rate of stillbirths increases over time is a "non-immortal" thing. That's an important limitation that will make your characters more believable. They're paying a price for their immortality.

Answer 4

Human Women are born with all the eggs they will ever have. Link to evidence

What this means is that, by default, your immortal women will stop being able to get pregnant at all eventually. (Even with endless youth).

I think this offers a solution to your problem. Perhaps your immortals have the unique ability to produce new egg cells throughout their lifetime, but that this magical new process that makes eggs later makes eggs that are more likely to be damaged. This would lead to higher a higher change of birth complications later in life when the eggs they were born with have run out and they are using the dodgy new ones.

Answer 5

We come from cells from our parents. Ever wonder why we start our lives at age zero instead of already having all the cellular aging from our parents?

At least in mammals, it seems that cellular aging is reversed right after fertilization.

If your immortals' cells don't age the normal way for our species, fertilized eggs may skip a step they need to do after fertilization, and this causes gestation to become unfeasible.

Answer 6

If you live forever (or very long) you will produce a lot of offspring. If all the offspring is immortal too it can get pretty crowdy. For sure that the genes in the eternals will be restructured to get less children (but to keep the joy of sex!). Maybe in the form of dead children (less children in the form of dead children...Is that correct to say?)

On top of that, life will eventually become a bore. This will have its reflection on fertility if its an enduring bore. You could argue that this will increase the urge for new young life but I think ultimately this will take its toll. Death children will be abundant.

Answer 7

What role could their natural longevity play in the creation of this problem?

To be absolutely clear, there is nothing 'natural' about their longevity. But it is part of the problem.

The Church of the Eternal Mother (SCP-4476) were created by altering adult human females (the Mothers, SCP-4476-1) to make them what they are today. Their longevity, reproduction and so on are the result of alterations made to them by the Grand Karcist Ion. Clearly those changes are genetic as their offspring - those who survive - are also long-lived.

Thus it's obvious that the root of their reproductive problems is in the genetics, mixed up in the changes that make their particular form of reproduction possible.

In normal humans pregnancy is the result of gametes from both parents fusing to form a zygote. The Mothers have been altered to use automictic parthenogenesis, where a zygote forms from gametes provided only by the mother. Rather than being strict clones of the mother, automictic parthenogenesis can result in variability of the zygote similar to that seen in classic sexual reproduction.

Sadly for the Mothers (but not for the rest of us), the many changes made to their genetic code are simply not viable for the development of a fetus. If a zygote is too similar to the Mother's full genetic sequence it will be still-born. The lucky few that receive only some of the altered alleles - the lesser half of the immortality complex for instance - are able to survive through birth and beyond. They are unfortunately rare, requiring a combination of multiple recessives in specific altered genes.

The SCP file notes that there are a high number of birth defects and physical abnormalities, which is additional support for the 'damaged DNA' hypothesis.

All is not lost however. The Church of the Eternal Mothers apparently has some ability with genetic manipulation. Their temple itself appears to be a living construct, and on at least one occasion they have created a new mother, apparently using reproductive organs from an outsider. It is possible that in time, and with enough source material, the Mothers could be altered to produce more viable offspring.

Let's hope they don't figure it out any time soon.

Answer 8

Bioaccumulation causes the issues in pregnancy.

Bodies of mothers can handle these toxins, heavy metals, radionuclide, chemicals and so on. But developing foetuses less so apart from few lucky ones. Thus early on there is better environment for development and it gets progressively worse as more foreign elements end up in body of mother.