I agree---sharp stomach pains is not usually a sign of pregnancy---sounds more like gas bubbles. There can be some sharp type pains in the low abdomen, in the area of the uterus, as it begins adjusting (getting ready for a lot of stretching). I had two of those, one quick on one evening, and one the next afternoon. It was my first suspicion. Some people call it implantation pain. It is usually accompanied by a mild persistent "crampiness" but not full on cramps.
Nausea honestly does not typically kick in for the majority of women who will experience it until about 6 wks or so. How far along do you suspect she is? The best way to find out is a home pregnancy test---just go to your local grocer/major retailer/drugstore and pick one up for a few dollars. You'll know in 5 minutes.
I agree with the above comment - have your wife take a home pregnancy test to see if she is pregnant. Symptoms mean nothing because there are NUMEROUS things that can cause them. If she is pregnant, she will need to see a doctor unless she wants to risk possible complications that could result in serious consequences for her and baby (death being one).
go get her a home pregnancy test, but sharp pains usuaaly is no a sign of pregnancy that i am aware of.