Is it harmful to have protected sex once during the menstrual period?
Having intercourse once during the menstrual period with a condom usually does not cause any problems if there are no discomfort symptoms. However, if discomfort occurs or the intercourse is too vigorous, it may have some impact.

During menstruation, a woman's reproductive system may be more sensitive, but practicing protected sex with a correctly used condom generally does not significantly affect health. Condoms effectively prevent sexually transmitted diseases and unintended pregnancy, even during menstruation. Therefore, if both partners are in good health and appropriate protective measures are taken, having intercourse once during the menstrual period with a condom typically does not result in significant adverse effects.
However, it should be noted that during menstruation, the cervix is slightly open. Even with condom use, intercourse might introduce pathogens into the vagina, increasing the risk of developing gynecological inflammations such as pelvic inflammatory disease and endometritis. Additionally, overly vigorous intercourse might cause menstrual blood to flow backward into the pelvis, increasing the risk of endometriosis, which could then have an impact.
It is advisable to maintain good personal hygiene during the menstrual period and try to avoid intercourse; waiting until after the menstrual period to have intercourse is preferable. If any physical discomfort occurs, it is recommended to seek medical attention at a hospital as soon as possible and follow the doctor's instructions for treatment.