Although there are no controlled studies that I am aware of, it is highly unlikely that use of a vibrator would cause any pregnancy complications.

For the majority of normal, healthy pregnant women, orgasm is a good release and often easier to achieve due to the increased vascularity of the perineum.

You may notice a temporary increase in the uterine irritability after orgasm, but this subsides quickly. If it does not, or contractions continue or get more frequent or intense, your care provider should be notified.

Orgasm is not recommended for those at risk for premature labor (history of premature labor, early cervical changes, increasingly frequent uterine contractions, history of infections during the pregnancy).