Thomson's violinist argument for abortion is based on an analogy between pregnancy and being coerced to serve as the life-support system for a violinist. In the course of the argument, Thomson says that pregnancy is the only case in which society (remember she is writing before Roe vs. Wade) requires a member to undergo a sacrifice of the magnitude that pregnancy involves.
My first remark is that this is simply false. There are two counterexamples to this: the draft and taxes. In the case of war, some members of our society are drafted. Being drafted seems pretty clearly at least as great an imposition as being required to continue pregnancy. It typically involves one's life being put under the control of higher officers in respect of just about every small detail, whereas only a few pregnancies require quite as much modification of one's life (cases where bed-rest is required for the length of the pregnancy are similar in this respect, though even then one is free to decide what activities to engage in while in bed, such as reading, writing, listening to the radio, etc.) The danger to life from the draft can be, depending on the conflict, significantly greater than that from pregnancy. Moreover, in being drafted, one becomes put under the orders of a hierarchy that can, and sometimes does, order one to engage in actions that are highly likely to result in one's being severely wounded, captured and tortured, or killed. (I expect that if I were to have to choose on grounds of self interest, I'd choose pregnancy over serving in the U.S. army in WWII, though I need to go on second and third hand data in both cases.)
The case of taxes is less clear, but still not implausible. Let's suppose Jennifer pays out 25% of her income in taxes. The imposition involved here may not seem grave when put in financial terms. But if we consider that in effect about nine years worth of work is commandeered over a 35-year career, this seems greater. Moreover, I suspect many people would willingly undergo a pregnancy in exchange for a lifetime exemption from taxation, and this would not be irrational in regard to self-interest. If this is right, then the imposition of taxation is comparable to that of pregnancy.
So, yes, our society does impose significant sacrifices on some members for the sake of others. It would be difficult, moreover, to imagine a society that did not have a draft when in danger of being overrun by the enemy, or that did not have taxation.
A second thing I find interesting about Thomson's argument is that as far as I can tell, abortions on account of the imposition represented by pregnancy and childbirth as such are relatively rare. With the notable exception of cases where the pregnancy itself constitutes a risk to maternal health and cases where the pregnancy reveals a relationship that the woman believes she needs to keep secret, standard reasons for abortion have to do more with not wanting the child to be born than with not wanting to be pregnant. In other words, most of the problems that lead women to abortion are such that the problem would not be solved by sci-fi technology that instantaneously grows the child to full term and beams her out into her mother's lap. The problem isn't with the pregnancy, but with the having of a child. But Thomson's argument defends abortion on the grounds of the imposition that pregnancy and childbirth as such make on the woman.
Now supposing that Thomson is right that the imposition of pregnancy and childbirth is indeed a morally sufficient reason for having an abortion. Then we would expect the challenges of pregnancy and childbirth themselves to be among the major reasons women cite for having an abortion. But apart from the cases where the pregnancy endangers the mother's health, the challenges of pregnancy and childbirth do not seem to figure among the major reasons for abortion. Granted, this may be because women are afraid it would sound self-centered to cite this as a reason. But since women seem willing to report that having a child "would change life in a way [they do] not want" or that they want to "establish [a] career" first, there does not seem to be a total taboo against citing self-centered reasons.
Moreover, Thomson's argument, if it were sound (and I think it is not), would only establish that there is a right to expel the fetus from the womb, not that there is a right to kill the fetus. But to satisfy the typical reasons why women have abortion, a right to kill the fetus would be needed. And Thomson's argument gives us no reason to think there is such a right.