Dickinson's sign: focal uterine softening in early pregnancy and its correlation with the placental site.

Focal uterine softening, characteristic of early pregnancy, is usually known as Piskacek's or von Braun-Fernwald's sign but should be attributed to Robert Latou Dickinson, who first described it in 1982. The presence or absence of Dickinson's sign was carefully noted in 1040 pregnant patients seeking abortions. The weeks of gestation, location of uterine softening, and correlation with placental site were also studied. This sign reliably showed the placental site, hence its unequivocal presence nearly proves the presence of intrauterine pregnancy and precludes the existence of tubal pregnancy. It was present in most pregnancies between 6 and 11 menstrual weeks, and its presence after 14 weeks should make menstrual dates suspect or signal the possibility of a septate or bicornuate uterus.