Do other animals have dangerous pregnancies just like humans?

Submitted by Level_Shift_7516 t3_10hqrx0 in askscience

TL.DR: Humans suffer during pregnancy, and many women die giving birth. Does that happen to other animals too? Are we too weak?

My wife is pregnant (Yey!). She struggles with nausea and tiredness, and everything doctors say is normal during the first trimester. In addition, she is scared about the possibility of miscarriage, complications and, in general, medical difficulties that could endanger her health (and the baby's health). She has been reading a lot about how, in the past, many women died because of pregnancy complications or while giving birth. Today, we wondered: is that kind of thing normal in animals?

I have never heard someone mention, "oh yes, my dog died because of pregnancy complications". I have never heard of that happening in wild animals. Maybe I am incredibly ignorant because I live in a city, but I am curious if other animals also have some rough times with pregnancy.

Is that the case? Or is it simply that we humans are weak?

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Comments

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Rcomian t1_j5av747 wrote

Humans are slightly special because of the baby's head, which is as big as it can be at birth. women's hips are as wide as they can really be without causing skeletal issues.

other animals haven't generally gamed their evolution in that particular way, we get more of an advantage from our brains than most. which makes our birthing process particularly traumatic for the mother.

other animals do get complications, as noted by others, but we're right on the cusp in terms of complications vs brain size optimisations.

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Mindshear_ t1_j5azc9o wrote

This is the best answer. Other animals can die, but Humans, and some select animals like hyenas, have an issue of trying to pass a large thing through a small hole which is especially dangerous.

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qwertyuiiop145 t1_j5ba86q wrote

There’s also the issue of the invasive placenta, another issue caused by big brains—the human placenta has blood vessels that burrow into the uterine lining to get maximum oxygen and nutrients from the mother’s blood supply. This can easily go wrong—too invasive and the placenta can cause bleeding and/or the placenta getting stuck, to little and the embryo can’t develop normally.

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The_Pale_Hound t1_j5cpl6v wrote

Thats combined with help during childbirth for hundreds of generations, so the strong selection against complications during childbirth that other animals suffer, it's lessened in our species.

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CapnPratt t1_j5atohq wrote

Animals die during birth if there's complications, cattle, horses and other farm animals have thousands of cases recorded and it's sadly common in rabbits and other small animals with large litter sizes. There's even animals that just die after they give birth almost always.

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Dalbergia12 t1_j5auk9n wrote

It absolutely happens in the wild. Since complications usually kill in the wild, the genetic predisposition to have any dangerous complications are culled out of the gene pool, so it happens less.

Many cattle and horses have very poor ability to give birth without help now. This is because they have had help for numerous generations. On cattle operations where because of geography and climate this doesn't work, ranchers are using bloodlines that have a strong ability to give birth unaided. An acquaintance developed a line of bulls whose offspring have smaller shoulders, the cows need no help almost ever. Breeding. Evolution. Darwin.

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mxjuno t1_j5dc204 wrote

We’ve only had our current birth interventions for a few generations. That’s not enough generations to make an evolutionary change.

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jrob323 t1_j5dsqcv wrote

It's likely humans have been helping each other give birth since we were human.

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Zeebuss t1_j5koxla wrote

For humans, midwifery is one the oldest and most ubiquitous professions in history, we've been intervening in birth for as long as know anything about.

Animal birth as well, animal husbandry is at least as old as agricultural, but domestication was already well underway among pre-agricultural nomadic societies.

Neither of these practices of artificial selection and assisted birth are "a few generations" old. They are ancient and absolutely have had enough generations for significant adaptation to occur. Also human artificial selection can happen much faster than that.

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mxjuno t1_j5ky5qq wrote

I was actually going to include that caveat but I tried to keep it simple. There are so many generations of wisdom in midwifery, and I’m absolutely sure it has made a difference over the generations. I used midwives myself for my births. I wish I could find the article that refuted that our anatomy would’ve changed that much due to interventions that humans use and animals do not.

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MartiniBikini7777 t1_j5mqyei wrote

Have you heard of the silver fox experiment in Russia ? A man took wild foxes and within 10 generations changed them from wild animals to the equivalent of domesticated dogs. So with constant conditions, evolution can happen relatively quickly.

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mxjuno t1_j5o9qej wrote

Definitely heard of it. I haven’t had as much time as I like to respond to comments but the most efficient way to say this is that we have not been selecting for characteristics that will create conditions for more dangerous or difficult births in such a concentrated way.

We are selecting for babies and moms who will survive the process of gestation and birth, which has changed in a way more nuanced way (ie we have lost some ways of moving and feeding ourselves which create more dangerous birth conditions, and we have gained a lot of tools that have increased survival of pregnancy and birth). That won’t change the mortality rates of pregnancy and birth in a huge way within a few generations of c sections and other more modern interventions.

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clusterfucken t1_j5b43g2 wrote

The rates of pregnancy mortality are naturally far higher than other mammals. This is hard to quantify, but pregnancy used to be a significant mortality risk not that long ago. I can't think of another mammal where this is the case.

Most of the reason why is walking upright. Evolution has to work with what it has and to take a quadruped and make a biped it came up with some less than ideal solutions. Our spines for example are terrible need to balance weight towards the back let's add some S curves. An "intelligent designer" would have been fired for that work around.

Our hips also had to change shape and shift back and forward and needed greater flexibility in the ball joints. Initially the sacrum became broader allowing the birth canal to become larger allowing for larger head seizes, but then larger head sizes were selected for. Birth canal size limited by the pelvis and baby weight (too low lower baby survival too high birth mortality) led to a high selective pressure around an ideal baby weight. Until recently it was of the best examples of optimized selection. Even with the high birth risks larger head size was still favorable so fetus skulls are born not fully formed which is why babies have soft spots in there head. The unfused skull can deform during birth to squeeze through the pelvis and why they can come out looking like cone-heads.

Walking upright and selection for increasing large heads made for a dangerous combination to human women and if there was an "intelligent designer" they really phoned it in.

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Ok_Bookkeeper_3481 t1_j5bbqx1 wrote

Pregnancy is an inherently dangerous for us, mammals.

I’ve read of lion cubs in breach position who would have died if not for veterinary assistance. And, of course, the whole body of literature on medical problems in domesticated animals.

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mtcwby t1_j5e1k3d wrote

Cows certainly do. Many years ago I leased my ranch to a local guy who was there before I bought it. There were a couple of things he did that I knew were a bad idea like running some really mediocre bulls with his herd and not controlling the access to the cows. Last straw was I found a way too young pregnant heifer dead in one of the pastures with a breech birth. I called the guy and he was sort of meh about it. I discontinued his lease the next month because he wasn't taking care of his animals like he should. My neighbor above us now leases it for less but is a hell of a lot better cattleman with a lot better cows.

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