As Melka said pregnancy can cause hemmerhoids which can rupture and bleed either from passing a hard stool or anal sex. So long as you have not been put on bedrest or pelvic rest anal sex is usually ok and does not harm the baby. HOWEVER, you should be especially careful that your partner does not remove his penis from your anus and rub it on your vagina or insert it without cleaning it really well first. Failure to clean it well can introduce bacteria from the anus into the vagina and cause harmful bacterial infections that CAN infect the baby. This goes for any type of penetration: penis, toys, fingers, etc.
The bleeding could be caused from hemmroids - when you are preggers blood flow is increased in the body and creates pressure on some areas - I have not had any - but I had some friends who had them and bled when trying to poo . If you have been put on pelvic rest - anal falls under the category of a no no as well... I have asked!
Hi,
Having anal will not risk your baby, as fas as the bleeding, you may need to try a lubricant before if he is not using one. Do not let him go from the back to the FRONT this could give you a really bad infection and possibly be harmful to your baby.