Can I get pregnant if I been on my period for 4 months?

Probably not. The normal menstrual cycle varies in length from 21 to about 35 days and last up to 7 days on average. If you have been bleeding for 4 months, something is not right. You may have a problem such as infection, polyps, adenomyosis, fibroids, neoplasia, etc. It is time for you to see your gynecologist for evaluation and treatment.