Anatomy & hormones
Oestrogen is mainly produced by growing follicles. In treatment it is also given as a medicine — tablets, patches or gel — to prepare the lining for frozen embryo transfer. Oestradiol is the main type measured in blood tests.
Also known as: estrogen, E2
Related United Kingdom guides
Sources
Last reviewed: 23 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.