UPDATE: interface scaling is not supported, starting at 1.4.12.

This affects Windows users only. While there is not a permanent fix, the workaround is to override the DPI settings for Maya.

1. Go to your maya.exe file (located somewhere in <Program Files/Maya version/bin>, right click and open up its properties.

2. Go to compatibility tab. Click on Change high DPI settings.

3. Edit the settings as shown below:

Further information about this issue: