What are the effects of HPV on pregnancy?

Typically none. Hpv itself will not harm your pregnancy. If you have developed genital warts from hpv, they often grow rapidly during pregnancy and can potentially cause obstruction to a vaginal delivery. If hpv has caused cervical abnormalities like dysplasia, you may need further evaluation of your cervix.
Usually none. Hpv can rarely affect a baby by exposure during the birth. The risk is low enough that there is no recommendation to avoid vaginal delivery even with obvious hpv.