The uterus is often described as being about the size and shape of a pear. But some women may have been born with differently shaped wombs that they’re completely unaware of until they try to have a child. In these cases the uterus may be heart-shaped (bicornuate), single-horned (with one fallopian tube), or divided (uterine septum), among other variations. These differences don’t always cause problems with pregnancy, but when they do, they tend not to interfere with conception, but to cause repeat miscarriages. Treatment for a malformed uterus depends on the individual problem. Some women with severe cases choose to create embryos with their partners and have a surrogate carry the pregnancy.