interlocking

A rare—circa 1:1,000 twin gestations—complication of vaginal delivery of twins; the 1st twin presents in breech and descends ‘locking’ his/her head above the head of the 2nd twin in vertex presentation; if the 2nd baby is already in the pelvis, loss of 1st baby is almost inevitable and interventional decapitation of 1st infant may be necessary to save the 2nd infant

interlocking

Obstetrics A rare complication of vaginal delivery of twins; the 1^st twin presents in breech and descends 'locking' his head above the head of the 2^nd twin in vertex presentation; if 2^nd baby is already in the pelvis, loss of 1^st baby is almost inevitable and interventional decapitation of 1^st infant may be necessary to salvage the 2^nd infant Prevention C-section. Cf Selective termination.