In theory the pre-marriage medical examination was not mandatory in the UK, but in practice it was to a certain extent. Back in the mid 60s through the 70s and 80s if a young woman wanted to go on the pill before her wedding day, as most did, then they had to go to their GP or the family planning clinic to be prescribed it. Before the doctor would do this they were given a medical that included an internal examination and breast examination. If they wanted this type of contraception then this medical was mandatory in most cases unless they had a very good excuse, and being a virgin wasn't an excuse. Some GP's would refer to these as pre-marriage medicals.
In the US I believe couples in the past had to have pre-marriage blood tests for fear of having a 'blue baby.' I recall a scene in the movie 'The Graduate' where these were mentioned. I don't know what would happen if the bloods were incompatible, was the marriage then banned or something? There were no such blood tests required in the UK, but back in the 80s all women would be given an injection very shortly after the birth of their first child that prevented this happening to the second child if they had one.