PORTSMOUTH, Virginia (Reuters) - Virginia's Republican Governor Bob McDonnell signed a law on Wednesday requiring women to have an ultrasound before an abortion but which left out a controversial requirement for a more invasive vaginal probe.

Women seeking an abortion in Virginia will now have to undergo an abdominal ultrasound in order to determine the age of the fetus.

McDonnell, a possible candidate to be the Republican vice presidential running mate in 2012, signed the bill after he and Republican lawmakers backed away from requiring a vaginal probe in some cases. That provision sparked fierce opposition from women's groups and abortion rights supporters who said it was demeaning.

(Reporting By David Adams; Editing by Greg McCune and Eric Beech)