Trace a line from your solar plexus down to your belly button.

Then sit leaning back on the couch or something.

Then pull your tummy muscles in and pull yourself into a sitting position - you should be using the muscles you would be using if you were doing a sit up.

Look at the imaginary line you traced.

If you can notice the muscles there pulling up so it looks like a little hill peaking at the imaginary line then you might have muscle separation.

Normally all your muscles would contract.

If there is separation you'll have this little channel of a hill running down your middle from under your breast bone down part of your baby bump.

I hope that makes sense!