I am on the birth control pill but my period was very light and lasted about 4 days. can i be pregnant? or is it common to have a light period

Lighter periods are: It is quite common that "periods will be lighter and shorter"while on oral contraceptive pills which usually reduce your risks of pregnancy (are 92 to 94% effective) but will not eliminate the possibility of a pregnancy. If you need to know, check your pregnancy tests. If you would like to feel safer and use the most effective methods of contraception, ask a knowledgeable and caring Gyn for a LARC