How and Why a Baby Is Delivered by Vacuum Extraction

Forceps have been around for hundreds of years, and although they have saved the lives of thousands of babies and mothers, they also can cause injury. The obstetric vacuum was invented specifically to address this problem. It is an alternative to using forceps to pull the baby through the birth canal. However, unlike forceps, the obstetric vacuum does not compress the fetal skull, and therefore reduces the possibility of injury.

Obstetricians and midwives often joke that it is a shame that babies do not have handles on their heads to allow them to be pulled out when they get stuck. The vacuum extractor, which has a handle attached to a plastic suction cup, comes close to fulfilling this wish. In a vacuum extraction delivery, as with forceps, the cervix must be fully dilated, and the fetal head must have begun its descent through the pelvis. In a vacuum extraction delivery, however, the mother must be able to participate actively. When the vacuum is turned on, the cup sticks to the top of the baby's head, so the obstetrician can pull on the handle during contractions, adding pulling force to the pushing forces of the uterus and the mother. Unlike using forceps, it is almost impossible to pull too hard; the suction cup will just pop off.

There are advantages and disadvantages to the vacuum extractor when it is compared to forceps. In difficult situations, such as a higher station or sub optimal position of the fetal head, the use of the vacuum extractor has a lower success rate as compared to forceps. However, the vacuum extractor requires less maternal anesthesia, makes the mother an active participant in the delivery process by enlisting her pushing efforts, and is less likely to cause injury to the mother or the baby. Although there are some situations in which one method is preferable to the other, for the most part, the decision should rest with the obstetrician. The best method is usually the one that he or she is best trained in and has the most experience with.

In which situations might vacuum-assisted delivery be offered to you? The situations are similar to those in which forceps might be recommended: a period of pushing with progress to a low station, such as +3, followed by minimal further progress; fetal distress during the second stage (pushing); or maternal exhaustion. The vacuum extractor cannot pull the baby out without the help of maternal pushing. The same important warning that applies to the use of forceps also applies to the use of the vacuum extractor: If there is evidence that the baby is too large to fit, a C-section is the appropriate treatment.

What procedures can you expect if a decision is made to use the vacuum extractor to assist the delivery of your baby? The obstetrician will attach the cup to the device that creates the suction (usually a hand pump) and test it against his or her hand. Then the obstetrician will apply the cup to the baby's head and examine it carefully to be sure that it is properly positioned. At the next contraction, the nurse will pump up the vacuum and the obstetrician will begin pulling while you are pushing. Between contractions, the vacuum is released. The process is repeated until the baby's head is delivered. When the vacuum extractor is used, an episiotomy is not always necessary, because the cup is small and flexible; it does not add to the diameter of the fetal head. You can see that there is much less preparation involved than for the use of forceps. There are no special anesthesia requirements, because the suction cup is soft and causes no additional discomfort. There is no need for bladder catheterization, either.

After your baby is delivered, you may be surprised and a little worried to find that the baby has a big bump on its head where the cup was attached. This bump (known as a chignon) is not harmful and will disappear in 24 to 48 hours.