You Do Need power plug adapter while traveling from Bahrain to Saint Kitts and Nevis.

Here is Why You Need An Adapter

The outlet and plug type used in Saint Kitts and Nevis are D and G and in Bahrain is G. This is how they look like.

Bahrain

In Bahrain, outlets of type G are in use.

Type G

Saint Kitts and Nevis

In Saint Kitts and Nevis, outlets of type D and G are in use.

Type D

Type G