Is it safe to have sex while pregnant?

Looks like some men may need a refresher course on sex ed: Most guys are afraid they could hurt the baby during sex while you’re pregnant, according to a new study published in the Journal of Sex & Marital Therapy.

In this study, researchers recruited 105 men between the ages of 20 and 46 with partners who were on average about 38 weeks pregnant to see how sex might change as a result of the pregnancy. The majority of couples had less sex while the woman was pregnant—but not because it was bad: More than half of the men said they were highly satisfied with the sex and the overall relationship. So why the dry spell? It turns out that 81 percent guys thought intercourse might harm the fetus. Other reasons they gave included not wanting to induce early labor or that their partner wasn’t in the mood.

Sure, logistically this fear seems pretty legitimate, but experts say it’s unfounded. In general, sex during any trimester is safe as long as you’re not suffering from any complications, says Mary Jane Minkin, M.D., a clinical professor of obstetrics and gynecology at Yale University School of Medicine, who was not part of the study.

“Intercourse is generally safe during pregnancy as long as it’s comfortable for the mom,” says Kiarra King, M.D., a Chicago-based ob-gyn, who was also not part of the study. This means avoiding positions that require you to lie on your back, like missionary—which may cause the uterus to press against the vena cava and reduce blood flow from your lower body to your heart. Instead, opt for side-by-side positions that take the pressure away from major body parts. Also, it doesn’t matter if a guy is, um, well endowed—the cervix blocks access to the fetus until about the last month of pregnancy. And even if the penis penetrates deeper, amniotic fluid surrounds the baby, which acts like a cushion, says Minkin.

In some cases, your doctor may even encourage sex. While it’s true that sex can induce labor, it’s only likely to happen if a woman is past her due date. Seminal fluid contains prostaglandins, which can lead to uterine contractions, says Minkin. And when it comes to your own libido, that may increase or decrease during pregnancy—it all depends on the woman.

So as long as you’re comfortable, in the mood, and not experiencing any complications, you can assure your guy that it’s perfectly safe to hit the sheets.