No ultrasound until 20 weeks?

Hoda
So I had my nuchal a few weeks ago (currently 15 weeks) and I wanted to have another ultrasound at 16 weeks to find out the sex. My doctor said that a "harmony" test won't be covered by my insurance because I'm not a "high risk" patient. I'm REALLY anxious to find out the sex and don't want to wait another month (crazy  preggo lady talk). Is there any way around this insurance Bologna?