Is it ok to use electric tooth brush when gums are sensitive/often bleed?

Yes, but....: Electric toothbrushes are fine, but I am more worried that your gums bleed. This has been linked to some rather severe diseases of the body- diabetes, heart attacks and strokes for example. If your dentist isn't addressing the bleeding- finding the cause and discussing how to treat it- get another dentist!

Bleeding gums: First, see your dentist for an exam to look for more unusual causes of gum disease or advanced disease. But for most "bleeding gums" complaints, it is lack of toothbrushing (and flossing!) which makes them inflamed and bleed. Then, when patients start to brush, bleeding makes them think stopping will "let them heal"--a mistake. It's ok to use any tooth brush, as long as it's being used regularly.

Yes: Electric tooth brush, or any kind of tooth brush as long as it has soft bristle, will not traumatize your gum nor your tooth/teeth. In fact, when gum bleeds or swollen, you should brush more in the area to eliminate the bleeding and reduce the swelling. Brushing will establish drainage of the localized infection and start the healing process.