Anna Smajdor and Joona Räsänen have an article at the Journal of Medical Ethics, Is pregnancy a disease? A normative approach. Their answer is that it is, on most accounts of 'disease', although they are quick, although not particularly persuasive, in claiming that a disease is not necessarily a bad thing. In reality, of course, it makes no sense to call the normal functioning of the species a disease, and pregnancy is one of the best candidates for such a thing -- if anything is normal functioning for a species, its usual form of reproduction is, and if anything is certainly not a disease, pregnancy is certainly not a disease. But it's worth noting how they build their argument, based on various claims that pregnancy has features associated with disease.
(1) One might identify something as a disease on the ground that it has harmful symptoms. But, they say, pregnancy shares many symptoms with diseases -- aches, bloating, swollenness, sleep problems, stretch marks, etc. Of course, exercise also shares many symptoms with diseases. The reason for this is that there are only so many ways in which major changes to the body can be accommodated, and many of the symptoms we are talking about here are just ways the body accommodates major changes; whether they are harmful or not just depends on how long they last, how extreme they get, etc. But it's true that 'harmful symptoms' is not a very good account of what a disease is; symptoms are just diagnostic markers, and most symptoms of most diseases are not actually harmful at all. There are very dangerous diseases who symptoms can be quite mild until they actually kill you. The point is, symptoms are symptoms; they are not defining characteristics.
(2) One might identify something as a disease on the ground that it is bad for a person in such a way as to be a misfortune that can be treated medically. The authors argue that even wanted pregnancies can fit this account; I think they are doing some tap-dancing with 'bad' and 'misfortune', and that the actual problem that their argument highlights is that they don't have a serious account of what it is for something to be bad or a unfortunate. But in any case, it runs into the same problem as the previous, in that we are trying to say what a disease is on the basis of things not strictly intrinsic to it. Anything can be messed with medically, so that if you wanted to interpret this account very generously, you can make anything count as a 'disease'. In reality, this account would only work if we are already implicitly restricting 'bad', 'misfortune', 'unlucky', etc., to cases that are relevant to diseases.
(3) One might identify something as a disease on the ground that this is what the medical community classifies as a disease. It's very clear that the medical community in general does not classify pregnancy as a disease, and the authors' attempts to get around this are not particularly convincing, I think, but the general point is right -- this can't be our actual account of disease. It's worth noting that, again, anything could turn out to be a disease on this account, unless there is something that actually constrains classification here. (There's a recurring pattern here, you notice.)
(4) One might identify something as a disease on the ground that it is dysfunctional. This is where, I think, their argument really starts breaking down a bit. Up to this point, there's been some stretching of what counts as 'harmful', perhaps, but the general point, that the accounts of disease can't get us what we need, has been right. But their argument against the dysfunction account of disease is actually quite bad, and in a way that is instructive. Their argument is:
(a) It's elitist. This is a non-starter as an argument, of course, because what they mean by 'elitist' is that it involves medically informed evaluation, which is not a correct use of the term 'elitist' in a medical context. It's also the case that, contrary to what they seem to suggest, not classifying a bad thing as a disease is not an elitist attempt to ignore the 'lived experience of the sufferer' -- it just means that medicine is not the relevant context for considering how to deal with that kind of badness. (I think this is worth emphasizing because there is an upsurge in people trying to claim things like, "Poverty is a medical problem". No, making such a claim is hubris; poverty may affect things that are medical problems, but part of good medicine is having the intellectual and moral humility to recognize that some problems are beyond mere medical competence.)
(b) It tries to get an 'ought' from an 'is'. As I have noted many, many times, on every serious account of reasoning we have, you can at least sometimes get an ought from an is -- for instance, the authors repeatedly assume in their own argument that if something is classified as a disease according to a given account (an 'is'), then people using that account should classify it as a disease (an 'ought'). This argument also would prove too much, since it would mean that we couldn't recognize biological functions at all, which creates far more problems than the one they are trying to identify. However, this is a secondary matter, in a sense, because the authors are making a mistake that is common when "You can't get an ought from an is" comes up -- they are assuming that we are actually starting with an 'is' rather than an 'ought'. This is significant here because medicine itself does not start with 'descriptive facts'; it starts with a sorting of kinds of descriptive facts into those that need to be addressed and those that don't. (This is one of the reasons, incidentally, why 'what the medical community classifies as a disease' will often get you a right answer but can't be the actual account of disease, because it's circular.) Medicine is like engineering in this way -- engineering doesn't start with physical facts, but with something that needs to be done. Medicine is the same way -- it doesn't start with biological facts, but with something that needs to be done. Engineering and medicine are practical, ought-based fields; they start with a set of problems that need to be solved, and therefore have to meet certain standards required by the problems themselves. These standards involve 'ought' already.
Thus their argument on this point fails completely. This is not surprising; the dysfunction account has always been the most resilient account of disease, so that no matter how many problems people may think they have identified with it, it never dies out and always surges back again. This is because, even if we assume that it is not correct, it actually does very well at least doing what an account of disease needs to do -- it's generally intuitive, it fits the way we tend to talk about disease, it allows us to shift back and forth between more theoretical and more practical perspectives, it gives a framework for defining medical problems in a relatively precise way and thus for finding medical solutions to those problems, etc.
(5) They then consider whether someone might think not in terms of 'function' but in terms of 'normal species function'. Their argument here is that pregnancy is not normal for men or young girls or elderly women, which is true but irrelevant. 'Normal' and 'Normal species function' are not the same thing; for one thing the latter very clearly and explicitly is talking about the species. They also note that not being pregnant is more common even for women of reproductive age than being pregnany, which is also true but irrelevant; the question is not whether it is the most normal thing, but whether it falls within the range of normal operation of the species in its survival and reproduction.Can we insist that something is a normal species function when most of the species does not exhibit it? Obviously, yes. Pregnancy is still quite common, and if it weren't, there would be no species; it's the central happening in the perpetuation of the species; thus it is a normal species function. In this whole section, they are tap-dancing with the word 'normal'.
(6) They also consider accounts in which disease is a statistical phenomenon. This of course brings us back to something that is extrinsic to the disease itself; and the authors correctly note that you can only get a statistical account of disease if you have already laid the normative groundwork that connects your statistical claims to something like disease.
Thus, the argument doesn't really seem to show that we ought to classify pregnancy as a disease; it shows that you can easily raise questions about accounts of disease that are too indirect, and it fails to give an adequate argument against the most promising accounts. What it really does is make clear that whether anything is a disease depends on things that are more fundamental than anything medicine deals with -- questions about badness, about normativity, about function, etc. This is absolutely true; it's why over-medicalizing things always has a bad result (you turn fundamental things inside out by trying to explain them in terms of things that presuppose them) and also why medicine is not purely a matter of whatever doctors decide. Medicine instead is a practical field and a humanitarian tradition that is suffused throughout with normative assumptions about good and bad. If you try to ignore this, you just get gibberish like 'pregnancy is a disease'.
