Sex during pregnancy is highly individual. Some people experience higher libidos when pregnant, some have lower libidos, and some don’t see much of a change. If you do want to have sex during pregnancy, it's safe, unless your doctor tells you otherwise. And that includes anal sex. So if you usually enjoy backdoor play, there’s no reason to stop having while pregnant.
“Anal sex while pregnant can be completely safe and enjoyable,” says Jennifer Driver, sex educator State Policy Director at the Sexuality Information and Education Council of the United States (SIECUS). “However, as with any sexual activity (pregnant or not), there are things to consider before engaging. For example, it is important to be aware of and clearly communicate comfort levels, express what is enjoyable and what is not, and have an understanding of both your own and your partner’s STI status.” As always with anal sex, you should use lube and be sure to clean the penis or sex toy — or change condoms — between anal sex and vaginal sex to avoid transferring bacteria.
Pregnancy does mean there are a few extra considerations to take when it comes to anal sex. The first is that hemorrhoids — swollen veins in the anus and lower rectum — can be more common during pregnancy. "Hemorrhoids can lead to discomfort, pain, and bleeding," Driver says. If you do have hemorrhoids, anal sex can irritate them. Constipation during pregnancy is also common, and can lead to anal fissures that could cause pain during anal sex. If you start having anal sex and you feel pain, stop.
Next, certain anal sex positions may be difficult or uncomfortable during the third trimester of pregnancy (and the same goes for vaginal sex positions). Doctors advise against lying directly on your back for extended periods of time during the third trimester, so you'll want to skip or modify positions like anal missionary. You may also want to modify other positions to make them more comfortable.
Finally, some people are placed on pelvic rest during pregnancy, meaning that they should avoid sex of any kind, as well as other activities that put pressure on the pelvis. Your doctor may place you on pelvic rest if you have a condition called placenta previa (in which the placenta partially or completely covers the cervix) or if you're at risk of preterm labor.
One benefit of anal sex during pregnancy is that the hormonal changes that affect the vagina don’t affect the anus. This means that some people prefer the feeling of anal sex to the feeling of vaginal sex during pregnancy. So if you want to have anal sex during pregnancy, go ahead and enjoy, unless your doctor tells you not to.