What would happen to the baby if you were pregnant and did not know it had your period used a tampon?

Using a tampon while pregnant and having a period is unlikely if you're pregnant. Once a person becomes pregnant, their menstrual cycle typically stops, and periods cease. If you're concerned about being pregnant, it's best to take a pregnancy test or talk to a healthcare professional. It is important to seek medical attention if you have concerns or suspect that you may be pregnant.