When can a girl not get pregnat?

Answer 1

The simple and the most correct answer to that is not to have sex.

I am a realist though, so in this day and age the best way you can protect yourself is to be on Birth Control AND to use condoms.

Pregnancy is only possible around a week either side of ovulation, as sperm can live in the body for up to seven days.

Unless you have made and kept extensive basal temperature charts and cervical mucus charts for a number of years and are an absolute expert at it, i.e. being completely in tune with your body and knowing exactly when you ovulate in order to plan pregnancy, you shouldn't use "safe time" as a reliable method of contraception.

The only sure way is not to do anything that can lead to sex or ejaculation with your partner, once sperm goes anywhere on your body , and you inadvertently touch that area and then, say, go to the bathroom without washing your hands thoroughly first, you could touch your vagina while wiping yourself and get pregnant that way, odd as that sounds.