As with any other procedure, there are risks associated with vacuum-assisted vaginal delivery. Even normal vaginal deliveries can result in complications in the mother and baby. In most cases, the vacuum extractor is used to avoid a cesarean section or to prevent fetal distress. When used properly, the risks of vacuum-assisted vaginal delivery are far fewer than the risks of cesarean section or prolonged fetal distress. Thus, when the vacuum is used properly, it may reduce risks significantly in both mother and baby.
Because the vacuum extractor has been used extensively in modern obstetrics, the possible complications of the procedure have been well-documented and range from mild cosmetic changes of the scalp to more serious problems.
Superficial scalp markings are the most common consequences of vacuum-assisted deliveries. Even after a normal vaginal delivery, it is common to see a small area of swelling that may give the baby's head a cone-shaped appearance-this is normal. The swelling results from the pressure of the cervix and birth canal on the part of the baby's head that moves through the birth canal first. In cases where the baby's head is tilted slightly to one side during birth, the swelling may be located on the side of the baby's head. This swelling resolves within one to two days following delivery. The original metal cup vacuum extractor produced a cone-shaped swelling on the top of the baby's head called a chignon. The chignon formation was essential to the success of the delivery. It was most obvious immediately after removal of the suction cup from the baby's head and resolved completely within two to three days. Occasionally, placement of the cup may have produced a slight discoloration with the appearance of bruising; this also resolved with no long-term consequences. The newer plastic or silastic vacuum cups do not require the formation of a chignon and are less likely to result in a large area of swelling. It is also possible that vacuum-assisted vaginal deliveries may result in small breaks in the skin. Studies have shown that approximately 10% of vacuum deliveries result in some sort of abrasion on the scalp. Difficult procedures that are prolonged or involve multiple detachments of the vacuum cup are most likely to result in scalp injury. These abrasions are most often superficial; complications have been reported, but they are rare and the lesions nearly always heal rapidly without leaving a trace.
Bleeding that results in a collection of blood under the skin (hematoma). Two types of hematoma can result from vacuum-assisted deliveries. Cephalohematoma refers to bleeding that is confined to the space under the fibrous covering of the skull bone; it occurs in about 6% of babies born by vacuum extraction. Complications of this type are rare, but the collection of blood may take one to two weeks to resolve. No special therapy is required to treat an infant with cephalohematoma. A more serious form of bleeding is subgaleal hematoma ; this occurs when blood accumulates just under the scalp. Traction that is not successful in moving the head may pull the scalp and the layer of tissue just under the scalp away from the skull, thereby injuring the underlying veins. This is probably the most dangerous complication of vacuum extraction because the subgaleal space is large and a large amount of fetal blood may be lost into this space. Fortunately, subgaleal hematomas affect only about 1% of babies born with use of vacuum extraction; they can also result from forceps-assisted deliveries, but to a much smaller degree and for different reasons. The use of the soft plastic vacuum cup has decreased the incidence of these injuries and when serious injury does occur, other contributing factors such as fetal bleeding disorders may be involved.
Neonatal jaundice may be increased in babies delivered by vacuum extraction, but the evidence of this association is controversial. Jaundice refers to the yellow skin color that is sometimes seen in newborns. It results from the breakdown of red blood cells and the subsequent production of bilirubin. Jaundice is likely to occur in a baby that has an abnormal collection of blood such as a cephalohematoma or subgaleal hematoma. Babies with significant jaundice may require phototherapy (therapy with strong lights that converts the bilirubin to a less toxic form and aids in its removal from the baby's system). In severe cases, the baby may need transfusions to decrease the levels of bilirubin.
Intracranial hemorrhage (bleeding around or within the baby's brain) is a very rare complication of vacuum-assisted vaginal delivery, affecting only 0.35% of babies born by this procedure. The traction applied to the baby's head may cause injury of veins and subsequent bleeding around the baby's brain. This complication is extremely rare and when it does occur, an anatomic or developmental abnormality is often also present.
Retinal hemorrhage (small areas of bleeding on the back of the eyes) is relatively common in newborns, regardless of the type of delivery. This condition is usually not serious; it resolves spontaneously and leaves no residual effect. As many as 28% of newborns have some retinal hemorrhage detected after birth. Although one recent study found the proportion of babies born with retinal hemorrhage was the same among normal vaginal deliveries, forceps-assisted vaginal deliveries, and vacuum-assisted vaginal deliveries, other studies suggest the number of infants with this condition is slightly higher among babies delivered by vacuum extraction. The exact cause of the retinal bleeding is unknown, but the fact that children born by cesarean section have a lower incidence of this problem suggests the pressure placed on the baby's head as it passes through the birth canal may be responsible.