This method of delivering a baby was developed as a gentler alternative to forceps. Similar to forceps deliveries, vacuum-assisted births can only be used with a fully dilated cervix and a well-descended head. In this procedure, a device called a vacuum extractor is used by placing a large rubber or plastic cup against the baby's head. A pump then creates suction that gently pulls on the cup to ease the baby out the birth canal. The force of the suction may cause a bruise or swelling on the baby's head, but it resolves in a day or two.
The vacuum extractor is less likely to injure the mother than forceps, and it allows more space for the baby to pass through the pelvis. There can be problems in maintaining the suction during the vacuum-assisted birth, however, so forceps might be a better choice if the delivery needs to be expedited.