Almost always, sex during pregnancy is perfectly healthy and normal. There are certain rare complications, such as low lying placenta (placenta praevia) or vasa previa where that may not be the case. Also, women with diagnosed preterm labor or women who would have significant bleeding, should talk to their doctor before having sex. Interestingly, sex can actually stimulate labor later in pregnancy. We know that foreplay, arousal, and orgasm can all stimulate some hormones that trigger labor when you are very near to term. You may find that your sexual arousal increases or decreases; you may also need to choose new sexual positions that are more comfortable for you and your partner. All of this is normal and ok.