Are you talking about pillows in general? or a tummy pillow? The tummy pillow is good to put on abdomen to keep it from hurting if you move, or cough, sneeze, or you think someone will accidently bump it. Ladies use several pillows to get comfortable to sleep or prop themselves up to relieve pressure or pain they might be having. I used a pillow to sit on because I had rectocle repair on my bottom. I used that for 6 weeks. I did not need one for my tummy I had a TVH.
It is a suggestion and some use them and others do not.
Your pillow will become your best friend for awhile. It aids in supporting those tummy muscles when you cough, sneeze, pass gas, etc. It is also extremely helpful in relieving pressure on your back when lying down, which you will be doing alot of for awhile. I used 1 for propping under my middle back, 1 for between my knees and 1 for wedging under my tummy. Shop ahead and get the most comfortable ones you can afford!
My advise is get all sizes, the fluffier the better (don't get hard ones, they won't be much good) .. I couldn't sleep in my normal position for 3 weeks, and had to get all types of pillow to get comfy in bed LOL .. It was like a pillow paradise nest in my bed, I counted them up one day .. I was sleeping surrounded and supported by 11 pillows !!
It also helped, 'cos if my DS came in to the bed (hes only young) I wasn't at risk of being kicked, from either him or DH !
For a tummy pillow something small is better. Whatever type of hyst you are having your insides will be kind of jiggly and tender and the pillow is to press against your tummy to support it or hold things still.
I used my hands instead of a pillow, except for riding in the car. Place one hand below your belly button, then the other hand on top of the first one, and press. You always have your hands with you, there are times (in the shower for example) when you can't have a pillow with you. Also sometimes sneezes sneak up on you!