Are U-shaped or straight body pillows better for pregnancy?

Across the pregnancy subreddits we read, U-shaped pillows are the most-recommended shape for late pregnancy because they support the belly and back simultaneously, so you don't have to reposition the pillow each time you flip sides. Straight 54-inch body pillows are cheaper and take up less of the bed, but they only support one side at a time. J-shaped and adjustable pillows are a middle ground for sleepers who find U-shapes too bulky or too hot.