Improving The Support & Softness Of Our Maternity Pillow

Our maternity pillow is in need of a major upgrade! I am looking to improve both the support and the softness of this pillow, and am open to testing different options to see what feels best. I need a more supportive filling that won't flatten over the 7 months that it will be used, but I have no preference when it comes to the filling material – memory foam, microfiber, natural fibers, or other – I want to try them all and see what works best. Finally, my budget for this project is more than $200.