This report has been promoted by a recent statement of Peters1 to the effect that he has been unable to find a single report of interlocking of twins in American obstetric literature. Furthermore, he brings out the fact that the Index Catalogue of the Library of the Surgeon General's Office covering the years 1912 to 1932 lists only three articles referring to this obstetric complication. All these are in the Swedish literature.
According to von Braun, the accident occurred in Vienna once in 90,000 labors. Coleman2 in 1935 reported two cases in each of which the two fetal heads attempted to engage in the pelvis simultaneously. A commoner type is the descent of one fetus as a breech. Various combinations are possible. Our case presented chin to chin, with the second fetus attempting to enter the pelvis before the head of the first had been delivered. Peters' case
Bowles HE. CHIN TO CHIN LOCKING OF TWINS. JAMA. 1938;110(19):1551-1552. doi:10.1001/jama.1938.62790190001007