Provera is the brand name, the name of the medicine it contains is called medroxyprogesterone. Its use during pregnancy is contraindicated (i.e. not permitted). Due to ethical reasons the drug has never been tested in humans during pregnancy. However animal studies have shown that Provera if given during early pregnancy, can cause masculanisation of female foetus (such as unwanted hair on face etc). It can also cause urogenital defects, more so in male foetus. One needs to keep in mind that sometimes the adverse effects noticed in animal trials are not applicable to humans. The issue here is whether you wish to proceed with pregnancy since the risk is minimal.