Hi Megan,
Not sure I have seen a study that uses the intradermal needles at the wrist to stimulate the anterior interosseus nerve for nausea. Lee in 2015 looked at AIN stimulation (PC6 in acupuncture terms) using a needle, and wrist band and found it helped Post operative nausea and vomiting (PONV) as well as antiemetic drugs. That said, stimulation the point makes sense in your application and certainly trying intradermal needles is worth a try- let us know how it goes. As far as stimulation the sensory branch of the vagus in the ear- again that is worth a try as facilitating the parasympathetics can only assist in your described case.
please follow up with all of us.

Hi Megan,

I am curious to find out if needling the Superficial Radial did in fact help reduce any nausea/morning sickness in your pregnant patients at your practice. 

Thank You