Vacuum extraction is a method to assist in childbirth using suction from a cup placed on the baby's head to help with traction during contractions. There are different types of cups including metal, soft, and bird's cups. Vacuum extraction is indicated when forceps cannot be used and has advantages over forceps like less need for anesthesia and less compression force applied. Complications can include maternal lacerations and cervical injuries or fetal issues like cephalhematomas and scalp lacerations.