Maternity clothes sizing?

Mariah • Happy wife and soon to be mommy to Audrianna Marie . 💕👣

So I am looking for a bikini to order and I need help choosing a size to get. I am 26 weeks pregnant and I use to wear a medium shirt before I got pregnant and size 11 jeans. Do I need to get a medium or Large bikini? I'm unsure of what size would fit good around my bump?