Can Stress in the Dam Affect Puppies in Utero? (Video)


The time is drawing close; in another couple of weeks, assuming that all goes as it should, Janice will give birth. I am, of course, a mess, as I always am when I have a pregnant dog. I alternate between feeling total joy at the prospect of welcoming puppies into my household and then placing them with good people, and wringing my hands in agony while condemning myself for putting Janice through this.

Realistically, in my saner moments, I figure that Janice is probably just fine with the whole thing. She’s pretty laidback and has no history of trouble delivering healthy litters.

Of course, all modesty aside, I provide Janice (and Leroy, too, of course) with a pretty nice life. There’s no reason why she shouldn’t generally feel pretty placid. My own stress got me wondering, though; if a dam is stressed, what are the ramifications? Could the puppies in utero also be affected?

Think About This

Not all dogs live like Janice, and not all breeding is planned, as hers was. It’s a sad truth that there are people out there who will simply dump a dog that is discovered to have become accidentally pregnant. In the best-case scenario, the dam will end up at an animal shelter, and depending on the quality of the shelter, may be mildly to moderately stressed up to the point where shelter staff is able to find her a foster home.

In a worse scenario, shelter staff aren’t able to find the dam a foster home, and she ends up spending the remainder of her pregnancy in the shelter, which is not exactly the least-stressful environment for a dog. It’s full of the sounds of other dogs in distress, all kinds of unfamiliar smells and noises, and it’s here that she spends the duration of her pregnancy and nurses her litter.

In the very worst scenario, it’s pretty much as described in the last paragraph, except that the dog’s owner hasn’t surrendered her to the shelter once it became apparent that she was pregnant. Instead, she was just dumped on the street, where she wandered in terror and had to scavenge for food and fend off attacks from other dogs until an animal control officer found her and took her to the shelter.

Obviously, any or all of this is going to add up to an animal that is incredibly stressed. Now, how does that affect the puppies in utero?

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How Much Stress Is Too Much?

Imagine that things go relatively smoothly for our hypothetical dog: her owner realizes that she’s pregnant, takes her to a shelter, and she’s immediately placed with a loving foster family. She will still have gone through a confusing, stressful period. How will stress in this dam affect the puppies in utero?

The thing here is that the brains of those puppies start to develop long before birth, and their hormones begin to be “tuned” very early on in order to help them be prepared for the world as it is experienced by the dam. This is actually a survival tactic; for animals that are born into stressful environments, a more highly developed reactiveness to stress can sometimes be a lifesaver. So, the answer to our original question is, “Yes, stress in the dam can affect puppies in utero.” It’s supposed to. It’s nature’s way of preparing the animal for life under harsh conditions.

The trouble is, though, when animals are born into conditions (like our hypothetical foster home) where this hormonal “tuning” is no longer needed, it doesn’t just go away.

How Does This Work?

In the animal world, the tuning occurs early on, so that the mother can pass on the information her offspring will need about the kind of world they’re about to be born into. An animal that’s under stress is going to produce cortisol, which is a hormone that tells the animal’s body that it needs to be ready to handle threats. With relatively low stress levels in the pregnant animal, the cortisol will stop at the placenta. When the stress level is high, on the other hand, at least some cortisol will pass through the placenta. This sends the message to the puppies in utero that the world is not a good place, and that they should be afraid.

The “stress system” of the puppies in utero has gotten an appropriate message. However, it could be one that they’re not able to discard when it’s no longer relevant to their situation.

Studies on Laboratory Rats

Studies have shown that laboratory rats born to mothers that were subjected to stress are born less able to handle stress themselves. They are, in short, hormonally “tuned” to anticipate stress, even if they’re never exposed to it.

I should note that there haven’t been any similar studies done on dogs, so all the theory on hormonal tuning when it comes to dogs is just that – theory. This is a good thing, since there wouldn’t be any way of conducting such a study without subjecting pregnant dogs to stress. However, there’s little reason to think that the effects would differ in canines.

So, what happens is that, at least insofar as we know, the dam passes information to the puppies in utero. Sometimes, though, that information is not applicable to a puppy’s situation; a puppy from a litter born to a stressed dam may never have an unpleasant day in his life. The information, however, is hardwired in his brain. This could very well be a factor leading to anxiety or aggression – perfectly useful emotions and attitudes in a “street dog” but neither desirable nor necessary in a pet.

A Word on Puppy Mills

The idea that stress in the dam can affect puppies in utero is one very powerful reason why you should never, ever buy a puppy from a puppy mill (or from a pet store, for that matter, since they’re generally supplied by puppy mills). There is, quite simply, no more stressful environment. For more on this, see 5 Reasons Why Puppy Mills Must Be Stopped.

And A Word on Shelters

It’s always best to know your breeder, and have a very good idea as to the background of the parents of any puppy you are considering adopting. However, if I told you that you should not adopt a shelter-born puppy, and most people took that advice, that would take an awful lot of adoptions out of the equation, and result in a lot of puppies being put down.

If you are going to adopt a shelter-born puppy, though, do everything that you can to socialize him early on. If he seems fearful, slow but steady is the way to go. Keep it low-stress, but still provide him with a lot of exposure to people and different situations. It might take a lot of work, and you may never make up for everything that your puppy has been “tuned” to while in utero. He might have fearful experiences, and if he does, you may need the assistance of a behavior modification specialist.

Avoiding Stress

I’m perfectly well aware that when it comes to Janice, I’m a bit overprotective when she’s pregnant. The last thing I want is for her to feel stressed. And now that I’ve been researching the effects of stress in the dam on the developing puppies, I suppose I have one more thing to obsess over.

Of course, I’m not going to wrap her in a bubble. I don’t imagine that most day-to-day activities are going to cause her any emotional discomfort, since she’s a pretty laidback dog.

Even for dogs who aren’t as calm as Janice, I don’t imagine that the “everyday” stresses in the life of a pregnant dog are likely to be harmful, either to her or to the puppies in utero. So, if your dog is pregnant, make sure she gets her veterinary checkups even if she’s not all that crazy about going.

I think it’s the extreme stressors that are the ones we need to worry about – the ones that are likely to cause cortisol to penetrate the placenta. Shelter situations, obviously, are better avoided. Things like shipping a dog by air would also probably not be a good idea (in fact, many airlines will refuse to ship a pregnant dog). I also wouldn’t introduce a new pet into the household until after the dam has given birth.

Related Content:

An Owner’s Guide to Getting Through the Dog Gestation Period (Video)
How Long Do Dogs Stay Pregnant? The Answer to This and 9 Other Canine Reproduction Questions (Video)
9 Vital Weeks – Caring for Your Dog During Pregnancy and Whelping

The Final Word

You’re never going to protect your dog against every single potential stressor, but it’s best to avoid the ones that you can. Given that we can’t really be sure how serious the effect of stress in the dam can be on the development of puppies in utero and following birth, it’s best to err on the side of caution.