While we know that cannabis can contribute to male infertility, „we do not yet know if CBD products made from cannabis might also have a negative effect,” explains Julie Lamb, MD, FACOG, medical advisor at Modern Fertility. CBD is so new that there haven’t been any solid studies to show that it’s safe in pregnancy, or specifically what effects CBD hemp oil would have on a fetus, she adds. In one study that was conducted on mouse embryos, researchers found that the compound anandamide, which is increased with CBD use, actually inhibited the development of embryos, she says.