Some Friendly Tips
Don't blow this job
While we have yet to hear someone admit to this being part of their foreplay, we'll pass along the most common piece of "oral sex during pregnancy" advice: Don't let your partner blow air into your vagina. (Yeah, we know you wanted to be puffed up like a balloon down there.) While not likely to be a problem, such an action could possibly cause an air embolism to enter your bloodstream, blocking off a blood vessel and putting you and the baby in a potentially life-threatening situation.
Cold sore? Keep away
If your partner has a cold sore on the mouth or lips, oral sex is a no-no. A cold sore is caused by the herpes simplex virus, and it can be passed on to you during cunnilingus, giving you genital herpes. Not only is that incurable and no fun at all, it can cause complications during birth. (It's also possible to become infected up to as many as 10 days after any sores/blisters have healed from an outbreak.
Not too late
If your water has broken, or your caregiver has told you to avoid baths, swimming and/or regular sex because your cervix is dilating (or for any other reason), you may be more vulnerable to infection. Be sure to get the oral okay from your healthcare provider first.
Don't back down
When on the receiving end of oral sex, try not to lie flat on your back -- especially after about the 20th week of pregnancy. In that position, your heavy uterus can press down on the vena cava (a major vein), causing abnormally low blood pressure, restricting the amount of oxygen getting to the baby, and possibly causing you to become lightheaded. (It's also pretty not very fun to feel like you have a big weight pressing down on you.) So if lying on your back is usually your position of choice, try propping yourself up on the bed instead, or try the sofa or an easy chair. C'mon -- get creative!