Two-cancer screening refers to breast and cervical cancer screening for women. If you cohabit within 24 hours before cervical cancer screening, it can damage the surface cells of the cervix and reduce the accuracy of cervical cancer screening. That is why you should not cohabit 24 hours before a two-cancer screening. Two-cancer screening generally refers to the screening of malignant tumors in two parts of women’s breast and cervix. Breast cancer screening mainly uses clinical examination, breast ultrasound and mammography. Cervical cancer screening usually involves taking specimens from the cervix, so it is important not to cohabit for at least 24 hours before the vaginal examination. You need to keep your vagina clean and should not douche for more than 48 hours before your cervical cancer screening. If you cohabitate within 24 hours prior to cervical cancer screening, it can damage the surface cells of the cervix and elevate the PH of the vaginal environment, leading to inaccurate cervical cancer screening results. Also before cervical cancer screening, you should avoid menstruation so that the results will not be affected. Note that cohabitation is also not recommended after cervical cancer screening because there is bleeding on the surface of the cervix, and you need to wait until the bleeding clears before considering cohabitation.