Ovulating while pregnant

When a woman gets pregnant, her menstrual cycle is blocked by the action of pregnancy hormones, and there is no maturation of new follicles until childbirth. However, it is possible for hormonal alterations to occur during the first weeks of pregnancy, causing alteration in this system and leading to the release of a new egg (ovulation). If unprotected sexual intercourse takes place at this point, there exists the possibility that the egg is fertilized and the resulting embryo attaches to the lining of the uterus. This phenomenon is known as superfetation.