by Dr Michele Brown, MD OBGYN
It’s your first baby. You have been laboring for 24 hours. Your labor has had no similarity with that of the mothers featured on the Lamaze videos. You are finally fully dilated and have been pushing for 3 hours with an epidural anesthetic for pain relief. Exhaustion has set in. The heart rate of the baby has started to have occasional downward spikes with pushing. The head is visible and almost deliverable but you have exhausted all your energy reserved for the big push. What should you do?
C-section?? Forceps??? Vacuum delivery??
Which is safest for both you and the baby?
This month we address this very common issue that occurs in over 12% of all vaginal deliveries.
The vacuum extractor was first used in obstetrics in 1849 by a fellow named Simpson from Edinburgh, Scotland. Due to technical difficulties, its use was abandoned. About 100 years later, Malmstrom designed another form of vacuum using a mushroom looking rigid device connected by rubber tubing to a vacuum source, which was very effective. Kobayashi developed the plastic flexible devices that we use today, which are inexpensive and disposable.
The use of vacuum extraction for expediting a delivery is determined by individual circumstances. What needs to be done in any specific situation is not absolute. Much of the decision making depends on the skill of the operator and the full consent of the laboring woman.
Indications for use include:
A) Prolonged pushing phase (second stage of labor):
For first babies-duration is approximately 2 hours without an epidural and 3 hours with an epidural.
For “Multips” (women that have given birth before) both guidelines are shortened by 1 hour.
Today there is increased flexibility on the length of the second stage. If the fetal heart rate is reassuring and progress is being made, thus indicating that the baby is tolerant and safe, mothers can continue to push.
B) Maternal medical indications
When mothers have certain medical diseases such as cardiac disease or pulmonary edema-it may be advisable to shorten the pushing phase of delivery.
C) Deteriorating fetal status
Hastening delivery may be appropriate when the status of the fetus is deteriorating such as those indicated by certain fetal heart rate patterns such as fetal cardiac decelerations.
When Should You Never Use A Vacuum?
One should never use a vacuum if the fetal head is not at the outlet or very low in the pelvis, when the operator is inexperienced in using the device, when there is uncertainty of the fetal position, when there is a very small pelvis, or when there is a suspected coagulation problem in the baby or mother. An obstetrician must also consider the estimated weight of the fetus. If maternal diabetes, obesity, excessive weight gain, and previous ultrasound reports point to a very large baby, operative delivery with a vacuum should be avoided.
What if the position of the baby is not exactly perfect as it descends–can we still use a vacuum? The optimal position for delivery of a baby is the face looking downwards with the back of the baby’s head underneath mom’s pubic bone. The head is generally nicely flexed in this position.
When the vacuum is placed on the correct position of the fetal head–which is on the sagital midline suture, about 2 cm in front of the posterior fontanelle in the back of the baby’s head (flexion point)-the majority of heads will naturally rotate into the correct position as the head descends and is delivered. If rotations involve more than 45 degrees off the midline, the vacuum is not generally employed.
When the head is in the opposite direction or posterior—i.e. baby’s face looking upwards—generally it does not rotate but gets delivered as a “lift-out”.
What Complications Can Occur With A Vacuum?
Overall, complications from a vacuum assisted delivery are small when the operator is experienced and patients are carefully and appropriately selected. However, maternal injury can occur from internal lacerations of the lower genital tract if the vacuum is accidentally placed on vaginal tissue instead of the baby’s head. In addition, maternal rectal tears with possible damage to the pelvic floor presents a risk, especially when the fetal head rotates or is in a posterior position. Careful inspection of the genital tract after delivery is essential.
Fetal injuries may occur, including scalp lacerations, intracranial hemorrhages, hematomas on the occiput, (9.8%) and even very rare life threatening subgaleal hemorrhages. With the new hand held polyethylene or combined polyethylene-silastic flexible cups, this is much less likely to occur. In addition, limiting the amount of suction attempts to under 20 minutes, with automatic pop-offs when certain pressures are exceeded, along with the operator releasing pressure in between contractions helps to minimize the probability of injury. The absolute risk of major morbidity is extremely low– 1 in 860 deliveries. Unfortunately, delivery failures occur often due to these frequent detachments of the plastic suction cup. The key is noting progress through descent of the fetal head with each traction effort. If descent does not occur, this technique should be abandoned.
Compared to vacuum delivery, the incidence of injury with forceps has virtually the same incidence of complications except for a higher rate of facial nerve injury due to pressure of the forceps on the facial nerve. The injury is generally transient. Anal sphincter injuries are also more common with forceps deliveries. Shoulder dystocias are less common compared to vacuum deliveries.
With a vacuum, force is exerted on the fetal scalp putting fetal vessels at risk for injury. With forceps, the force is on the fetal skull. Decisions are often made by the comfort level of the operator.
The more techniques used (vacuum and forceps) the greater the risk of injury compared to spontaneous delivery. Complications are generally low with all modes of delivery but were always greater if vacuum, forceps, or c-section was done during labor.
C-sections increase the risk of hemorrhage, fever, longer hospital stay with increased costs, and complications for future deliveries due to scar tissue both in the uterus and in the abdomen. Patients will often require a c-section for future births and have added risk of uterine rupture should they choose to labor in the future. C-section with labor with or without prior operative vaginal delivery has the highest rate of complications in the fetus of intracranial hemorrhage. The major risk factor generating complications may be the long dysfunctional labor rather than the mode of delivery. Disengaging a fetal head that is very low in the pelvis in a woman that has labored a long time also has high risk of injury to the fetal neck and brachial plexus.
The rates for complications are similar in all 3 modes suggesting that it is labor and not necessarily the mode of delivery that increases the risks of injury. Skill and experience of the operator are of paramount importance.
Patients should be informed of the risks and benefits of any procedure performed. This includes C-sections and operative vaginal deliveries. Many obstetricians are now creating documents that patients sign after full discussion with their obstetrician during their prenatal care or upon admission to the labor floor.
Due to the lack of training by residency programs and development of the necessary skill set possessed by their graduates, the number of operative vaginal deliveries has been declining and there is a shift away from forceps towards the use of vacuum. Skilled operators have used both techniques in some instances where the fetal head is brought to the outlet and then a lift is done with a forceps. However, skill is essential and the obstetrician must accomplish their first goal of rotation with descent before moving to the second technique. Most skilled obstetricians have had a vacuum pop off and then applied a simple forceps successfully. This is different from the situation in which there is a severe fetal distress pattern or cephalo-pelvic disproportion, where one technique is tried unsuccessfully and then a second device is attempted unsuccessfully leading to a c-section with a very high risk of injury and lasting neurological complications.
With proper training and carefully selected situations in a woman with an adequate pelvic size, vacuum and/or forceps delivery can be both time saving and life saving for the fetus and provide a safe, successful delivery for a mother who would otherwise require a more invasive C-section procedure. The C-section presents greater risk of morbidity and mortality for both the mother, and after a prolonged dysfunctional labor, higher risk of injury to the fetus.
Unfortunately, we are currently caught in a vicious cycle. The number of operative deliveries is declining due to fear of litigation, less available skill resulting from practices and standards of obstetrician training programs, and even patient refusal due to fear of harmful consequences . Regretfully, the fear of litigation is leading to a vicious cycle of less teaching, less use of forceps and vacuum, which lead to more bad outcomes due to poor training and resultant increase in invasive C-sections which are, generate higher rates of uterine lacerations which leads to more litigation.