What do systematic reviews say?

Transdermal oestrogens vs oral oestrogens

Transdermal oestrogens showed no clear difference in clinical pregnancy rate compared with oral oestrogens (low certainty).

• Endometrial preparation for women undergoing embryo transfer with frozen embryos or embryos derived from donor oocytes 2020 · Cochrane Headline outcomes only
  OR 0.86 [0.59, 1.25]
  3 studies · 504 participants
  Low