I took it until 11 weeks when I stopped both
estrogen and progesterone. My RE did say, however, that the
estrogen is not nearly as important as the progesterone, and like Helen said, some women don't use it at all. I was on the patch, so I basically just changed it every 3 days.
wfaMiracle: It also says not to take progesterone while pregnant, but without it, an IVF pregnancy would most likely fail. So it's totally fine to take both hormones in early pregnancy.