Sex

Should I avoid it? No. Most pregnant women having a "normal" pregnancy can continue having sex — it's perfectly safe for both mom and the baby, even up until the delivery. Of course, you'll probably need to modify positions for your own comfort as your belly gets bigger.
However, your doctor may advise against sexual intercourse if he or she anticipates or detects certain significant complications with your pregnancy, including:
a history or threat of miscarriage
a history of pre-term labor (you've previously delivered a baby before 37 weeks) or signs indicating the risk of pre-term labor (such as premature uterine contractions)
unexplained vaginal bleeding, discharge, or cramping
leakage of amniotic fluid (the fluid that surrounds the baby)
placenta previa, a condition in which the placenta (the blood-rich structure that nourishes the baby) is situated down so low that it covers the cervix (the opening of the uterus)
incompetent cervix, a condition in which the cervix is weakened and dilates (opens) prematurely, raising the risk for miscarriage or premature delivery
multiple fetuses (you're having twins, triplets, etc.)
What are the risks, if any, to my baby? You should not have sex with a partner whose sexual history is unknown to you or who may have a sexually transmitted disease, such as herpes, genital warts, chlamydia, or HIV. If you become infected, the disease may be transmitted to your baby, with potentially dangerous consequences.
What can I do about it? Talk to your doctor about any discomfort you experience during or after sex or any other concerns.