She's probably acting out because of the baby coming (and the normal "terrible two's"...
- give her some special one-to-one time doing something she likes or going somewhere she likes
- give rewards for NOT doing this behavior
- get her to "help" clean up (not the actual poo, but have her scrub an area nearby while you are cleaning....)
- try clothes that she cannot remove (pin the zipper to a sleeper, difficult clasp overalls, etc
- if those don't work, keep her in sight for a while... either on a blanket on your bedroom floor or something as unappealing so she won't want to STAY in your room forever!!
Kids this age love stickers, finger painting, coloring, bubbles, balloons.... find something she really, really likes and use that to your advantage.
Also, if her stools are too loose, it may be upsetting her tummy. Try bananas, rice, etc.
If her stools are too hard, also upsetting tummy: fruits, especially prunes & plums
GOOD LUCK!! And, don't forget to get some input from your pediatritian....