Do girls get periods tho they are pregnant?

No, women do not typically experience menstrual periods while pregnant.

Menstruation occurs as part of the monthly menstrual cycle, which is defined as the time from the first day of one menstrual period to the start of the next period. During the menstrual cycle, the uterus lining (or endometrium) builds up in preparation for a possible pregnancy. If pregnancy does not occur, the endometrium is shed through the vagina as part of the menstrual period.

When a woman becomes pregnant, the hormonal changes associated with pregnancy (particularly the presence of the hormone progesterone) will prevent ovulation (the release of eggs from the ovaries) and the menstruation from occurring. Instead, the endometrium will continue to thicken and develop to support the developing embryo and then fetus during pregnancy.

Therefore, the absence of menstrual periods is one of the first signs of pregnancy. If a woman is experiencing menstrual-like bleeding during pregnancy, it is important to consult with a healthcare professional to determine the cause and receive appropriate medical care.