My wife is three months pregnant on the first pregnancy and has a serious craving for pepper_ hot pepper,. does this have any-effect on the unborn?

Probably not: Many pregnant women crave unusual foods. Hot peppers are not known to harm the baby. They can cause heart-burn or diarrhea in mom. In super high doses, they may stimulate uterine contractions. In many cultures, spicy food is a regular part of mom's diet. There isn't any rigorous research on the subject but your wife should be fine eating hot pepper more often than normal. Best wishes!

Not really: The only issue would be if eating hot peppers causes her to have diarrhea. Diarrhea can cause some contractions to develop, though usually they are irregular and don't result in labor.