Linea alba pigmentation and umbilical deviation in nulliparous pregnancy: the ligamentum teres sign

To determine the incidence and direction of umbilical deviation in pregnancy at term in nulliparas with linea alba pigmentation.

All women attending one prenatal clinic over a period of 19 months were available. Subjects studied were the 315 nulliparas whose pregnancies had reached at least 37 weeks' gestation. The presence of linea alba pigmentation, with or without umbilical flattening and/or deviation, was assessed with the woman lying symmetrically on her back on an examination couch.

Forty-four of the 315 women (14%) had sufficient pigmentation for assessment; 27 of the 44 (61.4%) were born in Asia or the Indian subcontinent, although such women comprised only 13.5% of the clinic population. In 31 of the 44 women (70.5%), the umbilicus and supra- or infraumbilical linea nigra was deviated to the right side, and in 13 it remained in the midline; in none was there deviation to the left side.

Displacement of the umbilicus and adjacent structures commonly occurs in term pregnancy; pressure of the uterus on the ligamentum teres and falciform ligament determines that displacement is invariably toward the right side.