Many woman like to overdo AB exercises, hoping to achieve a smaller more flat stomach.

There are certain things you need to be aware of:

1. Very strong and tight abs can become an issue in your monthly cycle, as the contraction and lower body cramps also influence the abdominal area.
2. After a pregnancy the rectus abdominus can be separated (in the middle line) and might cause problems when being trained. Sometimes surgery may be needed to help with this. Should you encounter any extreme or stinging pain in this area, consult your doctor.
3. When you train your abdominals, you also need to train your back! Too much training on one side of the body leads to bad POSTURE (due to the muscles contracting more on that side, pulling the bones towards that position), other imbalances which can lead to more pain and weakness in certain movements.

When you have regular sized or bigger breasts, woman have a tendency to, by default, bend forward slightly. Working the back and ab muscles will contribute greatly to your posture.

Check out the video below about how to align your spine!

How To: Postural Alignment- Part 1

Related Questions:

1. How should I be training my abs?