Surrogacy is an assisted reproduction technique that, as such, carries some risks.
If we are talking about medical risks, we must bear in mind that actually surrogate mothers are not the ones who provide their eggs, so the treatment for them begins at the moment when they must be medicated in order to prepare their endometrium for the transfer of the embryo.
The medication in these cases is not very strong, but it is still medication. Once the transfer has been carried out, 15 days will be waited to determine if pregnancy has been achieved or not. And, from that moment on, the risks are exactly the same as those of any pregnant woman.
As far as psychological damage is concerned, I believe that the good choice of the gestational carrier and the responsibility when doing so are what will really determine whether it is a natural process or whether it ends up being a painful process.
It is fundamental that the pregnant woman freely chooses to participate in this technique, that is, that no family member, friend, or her economic situation forces her to do so.
Evidently, there is an economic compensation, but this should not be what really drives a woman to gestate the child of another person: there must also be a reason for solidarity, the desire to help a family. This is what really makes the difference.
Women who have this clear live pregnancy as a precious process and at all times are very clear that the baby that grows in their womb is not their child.