Here is some position of the fetus during parturition and lead to dystocia. 


Anterior/posterior presentation
Anterior/posterior presentation


Ventro/dorsal transverse and  bicornual position
Ventro/dorsal transverse and
 bicornual position


Dog sitting position in the horse
Dog sitting position in the horse


Ventral anterior and
 posterior presentation


Carpal flexion
Carpal flexion


Breech presentation
Breech presentation


Lateral deviation

Lateral deviation

Ventral deviation
Ventral deviation



Note:- Image credit to respective owner.