It’s common for pregnant mamas to prefer one type of pant or another, and to stick with the style they first felt comfortable with. Some will fall in love with a high-band pant during a winter pregnancy for the extra warmth and comfortable hug around the belly. Then, as that pregnancy continues into warmer weather, that extra layer of fabric can get warm so they opt to switch to an under-bump pant or short. Some still find the high-band comfortable regardless of temperature, and therefore pants and shorts can be found in either style.
A money-saving tip if you plan to switch back and forth between high-band and under-bump pants is to get a pair of under-bump pants and wear a tummy band with them to get the warmth and feel of high-band pants when you want them.