Relief from dystocia followed by spontaneous resolution of nuchal cord

We reported the cases of relief from dystocia, which were thought to be brought by spontaneous resolution of the nuchal cord. During labor, 8 cases of protraction or arrest disorders with cords coiled halfway around the neck were examined by color Doppler sonography. The cord lengths were measured after birth (''real cord length'') and compared with the ''loop length'' defined as the distance from the umbilicus via the posterior neck to the umbilicus of each baby. The ''usable cord length'', defined as the real cord length minus loop length, was also calculated. The usable cord length ranged from -5 cm to 13 cm. Coiling of the cord resulted in a marked reduction of usable cord length. We concluded that resolution of nuchal cord was necessary for relief from dystocia in these babies.