In ancient Roman religion, the di nixi, also Nixae, were birth deities. They were depicted kneeling or squatting, a more common birthing position in antiquity than in the modern era. The 2nd-century grammarian Festus explains their name as the participle of the Latin verb nitor, niti, nixus, "to support oneself," also "strive, labor," in this sense "be in labor, give birth." Varro said that enixae was the term for women in labor brought about by the Nixae, who oversee the types of religious practices that pertain to those giving birth. In some editions of Ovid's Metamorphoses, a phrase is taken as referring to the birth goddess Lucina and her counterpart collective, the Nixi.

Squatting is a versatile posture where the weight of the body is on the feet but the knees and hips are bent. In contrast, sitting involves supporting the weight of the body on the ischial tuberosities of the pelvis, with the lower buttocks in contact with the ground or a horizontal object. The angle between the legs when squatting can vary from zero to widely splayed out, flexibility permitting. Another variable may be the degree of forward tilt of the upper body from the hips. Squatting may be either full or partial.