Vaginal delivery is not possible in which of the following positions of fetus?

Ans. c (Mentoposterior position). (Ref. Textbook of Obstetrics by Dutta, 4th ed., 396, 409, 420)OCCIPITOPOSTERIOR:-# 1st stage: In uncomplicated cases labour conducted in usual manner, however special instructions as for occipito- posterior position is to be followed and hoping for spontaneous anterior rotation of chin.# 2nd stage: If anterior rotation of chin occurs spontaneously - then use forceps for further delivery.# But if incomplete or malrotation persists -LSCS will be ideal, however manual rotation may be tried.# However occipitoposterior per se is not an indication for LSCS.# Pelvic inadequacy, unfavourable configuration of pelvis and fetal anomaly usually need LSCS.