By using contraceptives, and using them right. Don't bother with "rythm methods" or counting days. Your body isn't clockwork-perfect so they're not reliable.
avoid having sex without protection...
== == YOU CANT IF YOU ARE PREGNANT YOU JUST ARE PREGNANT. bUT YOU CAN GET AN ABORTION IF YOU DONT WANT TO DEAL WITH THE PREGNANCY.
No but you should avoid it if pregnant since it is not tested on pregnant women.
Don't get pregnant
abstinence
Do only fat people get pregnant? No. So the answer is no, excercise does not help avoid pregnancy.
use a condom fool
Some of the main things a woman should avoid while pregnant are smoking and drinking. Along with these is to be sure and not do any types of drugs.
No you should avoid those when you are pregnant. And even if you weren't pregnant I would recommend that you never have that where you sleep.
I would avoid anything with artificial sweeteners while pregnant or nursing.
Avoid surgery that is not necessary when pregnant. Sedation can have side effects.
No but she needs to change it so it fits her better. Exercise is very important when pregnant.