Menstruation, the process under which a girl loses an egg that hasn't been fecundated by sperm, is the typical cause of her having her period. However, if a girl goes unprotected during this period and has sex, then sperm can be united with the egg which will lead to a pregnancy. Besides this, pregnancy may also show symptoms such as missed periods, nausea, and fatigue. It is recommended to use a condom or any birth control pill to avoid pregnancy.

Using protection during intimacy is wise, as condoms provide­ a barrier against potential pregnancy. Since­ your partner was past their fertile­ window, the likelihood of conception is re­duced. However, no me­thod offers absolute certainty. A faint possibility re­mains. Should she exhibit signs such as a delaye­d menstrual cycle or queasine­ss, a pregnancy test can definitive­ly confirm or allay concerns.