Is it true that if a woman has had her regular menstrual period, she is not pregnant?

Patient's question:

Is it true that if a woman has had a normal menstrual period, any previous sexual intercourse with her partner will never result in pregnancy? If she does get pregnant, would the child still be considered the child of the person she had sex with after her period, right? Is this scientifically accurate? Does it mean that the genes of the person she had sex with before her period have no relevance? Thank you, doctor

Doctor's answer:

If menstruation occurs, it means you are not pregnant. If you are pregnant, menstruation will never occur. If you are pregnant, it means you conceived after your period, and it has nothing to do with sexual activity before your period. It also has nothing to do with the genes of the previous person. The above is advice on the question "Does having a normal menstrual period mean you are not pregnant?" I hope it helps you. Wishing you health!