I suppose another way of looking at the question is: how important is gravity for the development of mammal fetuses?
And if things would go wrong, what sort of things would they be, and what would be the result?
There is some evidence that fetal development under zero gravity conditions might be problematic.
The paper is here.
These authors studied aspects of reproduction of mice in a clinostat under 10-3G. They found that fertilisation was unaffected, but that preimplantation development of the embryo was affected by the mG environment.
The introduction to the paper gives a good brief review of this area of research. Perhaps of particular relevance is this section:
Schenker E, Forkheim K (1998) Mammalian mice embryo early development in weightlessness environment on STS 80 space flight. [This is the citation in the paper, and I am unable to find the full citation!]
Serova LV, Denisova LA (1982) The effect of weightlessness on the reproductive function of mammals. Physiologist 25: S9–12.