 [ Symptoms ] can bad blood circulation cause small penis girth for an adult  to be more specific i am 25 years old quite overweightobese and am slightly below avg in girth since being overweightobese can cause a myriad of health issues regarding bad blood flowcirculation could this cause a lack of blood in the penis leading to a smaller girth would losing weight and improving blood flow increase girth would the gains be noticeable [ Disease ] you need to get to the er now with your medical history it is not that important when you started bleeding but rather how much you are bleeding right now a rapid bleed in the stomach could cause black stools relatively fast because you are weak and out of breath it would not be wise to delay an immediate medical evaluation