Lots of research has been done about what you can add to prevent dogs from eating feces. Nothing reliably works except removing feces before the dog has a chance to eat it. Some of them do largely grow out of the tendency.
I have a 10-12 year old rescue and she lives to eat poop. I have tried everything. It is very hard. The only thing you can do is go out with your dog and pick it up as she goes.
I have 5 Labs and she beats me to it everytime. It is hard to keep her inside when the other 4 are out.
I tried the pills, pineapple, etc. I try to do the yard twice a day when I can. Otherwise she has me up all night long. If it is raining hard, forget it.
*Hello*...everyone who has replied has told you it does not work...so why even give it? If your friend wants to know what the effects would be on her pregnant bitch she should ask her vet ...even though he is recommending something that does not work.