Describe the ectocervix, the transformation zone, columnar and squamous epithelium.
On the ectocervix there is a transformation zone where the stratified squamous epithelium meets the columnar epithelium of the cervical canal.

What does excess estrogen (Ovulatory phase, pregnancy, COCP) do to the ectocervix & what can this lead to?
It results in a larger area of columnar epithelium being present on the ectocervix.
This can then lead to cervical erosion (less used now) but basically non-purulent vaginal discharge and post-coital bleeding.

What is used to treat it and when would it be appropriate?
Ablative treatment can be used but only if troublesome.