Hello, this is Dr. Brown. Northisterone is a synthetic form of progesterone, which is a normal hormone during pregnancy. So even if she is pregnant it will not harm the fetus. She should finish the Northisterone as recommended and her period will come during the week following. If she still has no period after that, she should do a pregnancy test. And if she had taken the pills it is not harmful. Even birth control pills do not cause problems if the are accidentally taken in pregnancy. I hope this advice was helpful and answers your question.