I would say make leggings your best friend. I have to wear black pants where I work & I got lucky I found black sweat pants at dollar general for $8 plus I can wear them afterwards too. I wear dresses when I'm out & about running errands sometimes.
Sweat pants, leggings, big shirts, long skirts, yoga pants. I am almost 39 weeks pregnant and haven't bought any maternity clothes. I just wear comfy things all the time. Gave up jeans completely around 20 weeks.