For women with a 30-day menstrual cycle, except for ovulation and the 4 to 5 days before and after, all other days are safe periods, but it should also be noted that there is no absolute safe period.
If a woman’s menstrual cycle is 30 days, generally around the 16th day of menstruation for ovulation, because the egg or sperm will survive in the fallopian tube 1 to 2 days, so in the 12th to 21st day of menstruation sex may be pregnant, and other time is generally not pregnant, that is, the so-called safe period, but there is no such thing as an absolute safe period.
If both men and women do not need to have children, it is recommended that they use condoms to avoid unwanted pregnancies. At the same time in the female menstrual period is also not recommended to cohabit, menstruation female body resistance is relatively poor, cohabit will easily lead to vaginitis, pelvic inflammatory disease and other gynecological inflammation occurs.