I would seek a second opinion I've never heard or been told spotting in the second trimester is normal did they give you a full exam with a ultrasound to see where the bleeding is coming from?
I spotted at 11 weeks which my OB doctor told me was normal. He told me he would be concerned if I was spotting after 13 weeks. Spotting during the second trimester is not typically normal. I would get a second opinion or talk to your midwife about it again.