Generally, pregnancy is caused when sperm cells from a man come in contact with one or more egg cells in a woman. The most common way that happens is standard, penile-vaginal intercourse. That means inserting the erect (ie., hard) penis into the woman's vagina and moving it in and out until the guy gets excited and ejaculates his semen into her. Semen is a white fluid that contains sperm cells and comes out of a man's penis.
There are other ways to cause pregnancy besides penetrating the vagina with a penis and ejaculating. For instance, there are medical fertility procedures, where semen or fertilized egg cells are introduced without using a penis.
There are also careless acts and freak sexual accidents. One example is touching a girl with a hand that you masturbated into immediately after masturbation. In rare cases, unprotected anal sex would allow enough semen to drip into the vagina. That is uncommon, but possible.
To be complete, things that don't cause pregnancy needs to be mentioned. You cannot get pregnant through oral sex, anal sex, solo masturbation, nor sex with members of the same sex. The only possible way that pregnancy could occur during sex between two women would be if one immediately had unprotected sex with a man or was otherwise covered with semen and she somehow introduces it into the other woman. Similar is true with masturbation in that a woman cannot get pregnant from that unless the hands or toys used are contaminated with fresh semen from a virile male.
No they do not cause pregnancy.
No it doesn't cause, prevent or end a pregnancy.
Cuddling won't cause pregnancy.
No, pregnancy does not cause blue sweat.
Yes, lithium can cause a false pregnancy on a pregnancy test.
White secretions won't cause pregnancy.
Sharing a bath won't cause pregnancy.
Pregnancy may cause your feet to swell.
While it doesn't actually cause pregnancy, it can be a prelude to it.
backache doesnt cause pregnancy no, but pregnancy can cause backache. although keep a watch on how often the pain comes, it could be a sign of labor.
Pregnancy does not cause inflammation in the uterus. Inflammation of the uterus during pregnancy would serve no biological purpose.
No, sperm are required for pregnancy.