The research about the benefits and risks associated with oral sex in pregnancy is limited and very often contradictory. There is nothing that indicates that oral sex is recommended in place of penetrative vaginal sex unless you have been advised to avoid sexual intercourse because of the risk of bleeding, threatened miscarriage or premature labour, where avoiding orgasm is also advisable and so complete abstinence is the better option for a while. However it is also important to remember that some infections can be passed on as easily during oral sex 1
1 Dailard C, Understanding 'Abstinence': Implications for Individuals, Programs and Policies.
The Guttmacher Report on Public Policy December 2003, Volume 6, Number 5