Of significance for scuba, possible side effects of estradiols like Femoston include dizziness, lightheadedness, headache, nausea, mental/mood changes, calf pain/swelling, chest pain, trouble breathing, one-sided weakness, slurred speech & vision changes.
You certainly will want to give this medication an adequate topside trial before diving to see which, if any, of these possible adverse reactions you may develop on a continuing basis.
This is educational only and does not constitute or imply a doctor-patient relationship. It is not medical advice to you or any other individual, and should not be construed as such.
Best regards.
DocVikingo