Forceps should NOT be used in:
As discussed previously—
One of the criteria to be fulfilled before applying forceps is—there should be no major cephalopelvic disproportion (CPD) by clinical pelvimetry and hydrocephalus is an important cause of CPD.
Dutta Obs. 7/e, p 352
Twin delivery
Hydrocephalus
Post maturity
After coming head of breech