picker.ionChange is not detecting first change of every column

Ionic Framework ionic-v3
1

Hello,

I am using ionic 2 and used picker component.
I am using below code that will be called whenever any column of picker has been changed.

picker.ionChange.subscribe(() => {
      console.log('changed');
    });

I have just put a console log whenever any column of picker has been changed.
But, when I am changing any column for the first time, it is not detecting change.

Please help.