Bathroom lighting safety regulations are fairly straightforward and involves the bathroom being split into zones, with each zone determining the correct IP rating required for the light fittings used inside.
Zone 0 covers where light fittings are most likely to get wet (inside the shower or bath for example) and stipulates a rating of IP67
Zone 1 is within splashing distance (such as around the sink and bath) and requires IP44 or ideally higher
Zone 2 is further away from splashes, at least 60cm radius from any tap, and requires at least IP44.
Zone 3 applies to bigger bathrooms and is well away from water. There is no IP requirement in this zone unless water jets are likely to be used when cleaning (for example a shower hose in a large wet room).