Condoms and pregnancy may seem like a contradiction in terms but if either of you have an infection it is wise to use them. Using rubber dams (a flat piece of latex rubber that can be placed over the woman's genitals to prevent the exchange of body fluids, available in a range of colours and flavours from chemists) for oral sex would also be recommended.
The use of condoms and dams would be advised if one of you were positive for
Hepatitis B or
HIV / AIDS, having an active outbreak of
genital herpes or if you are treating conditions such as
thrush or
gardnerella.
Once the waters have broken there should be no penetrative sex to avoid infection, but orgasm is OK. You may wish to read
Waters broken, no contractions.