Yes they can, though the effect varies on the kind of pill you are taking.
In all cases, taking the pill obviously changes the timing of your period (you get them about 2-5 days after you start the placebo pills). Regarding how much or how painfull your period is, the newer generation of Birth Control pills tends to have either no effect, or reducing the amount of blood loss and cramps, and in some cases, no blood loss at all. Most women do not mind this side effect and it is not harmful.
A woman's menstrual periods are regular and usually lighter when she is taking oral contraceptives
Some pills can affect birth control. If your ill this can sometimes effect birth control too. You need to speak to a medical professional to find out for definite but its possible malaria pills may affect your birth control.
Women can take the birth control pills continuously without a break to skip the periods.
Asprin doesn't affect birth control.
This condition may improve or may get worse with the use of birth control pills
You should not mix pills with your birth control pills. This candamage your insides or cause your birth control to be ineffective. Mixing pills is dangerous.
Birth control pills have no effect on pregnancy tests.
It is known to reduce the effect of birth control pills
Yes, missing birth control pills increases the likelihood of getting pregnant.
There are no drug interactions between vitamin D pills and the birth control pill.
Green tea pills do not effect birth control. They may slightly speed up your metabolism but will not affect your hormones.
You shouldn't be taking birth control if you're not prescribed it. Birth control pills don't stop periods, they stop pregnancy.