Originating from WWII, the pinup girl would go on to become more prevalent in 1950’s art and culture over time. While the original pinup was intended for soldiers and other war-stricken people as a boost in morale, the pinup girl would go on to gain a more sexualized reputation in the 50s. Appearing in everything from advertisements, to magazines, and to movies. These art pieces and photographs commonly featured a woman of average weight and height with an hourglass figure, posing in a way that, while not explicit, was meant to be sexual. In many cases, ‘pin ups’ were not considered traditional art, and in the minds of the art critics of the time these illustrations were considered cliché.
With this in mind, one can see how the popularity of pinups might have influenced Willem de Kooning’s Woman I. Whereas it was considered overdone to portray a nude woman as the center of one’s art piece, de Kooning subverts the standard expected by the viewer of the time period by picturing a woman as anything but dainty and desirable. For this reason, one could argue that de Kooning may have been both trying to reimagine the pinup, while also defending them by creating fine art of a woman during a time when doing such was considered overdone.

https://www.kingandmcgaw.com/inspiration/post/history-of-the-pin-up