The darkening of the thigh roots after pregnancy is most often a normal physiological phenomenon, but it can also be tinea cruris. When the endocrine and immune systems of pregnant women change after pregnancy, the secretion of hormones and serum concentrations are dynamically changing, which may be related to increased levels of progesterone, estrogen and melanocyte-producing hormones in the serum and can lead to diffuse hyperpigmentation in most pregnant women. The pigmentation usually occurs in darker areas such as the nipples, areola, navel, genitalia, groin and midline of the abdominal wall, resulting in darkening, which usually fades after delivery, but most do not return to their original color. Another condition is tinea cruris in the groin, which is caused by a fungal infection that, in addition to darkening the skin, is accompanied by flakes and pimples with an itching sensation.