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I have, in recent weeks, been thinking about vacuum extraction, instrumental delivery, and the developments within the subject. This week, I am pondering whether it is dangerous to undergo an instrumental delivery, both for the mother and/or the baby.
Some of the women I meet at our clinic say that they absolutely do not want to be delivered using a vacuum extractor. Some even want it noted in their medical records that a vacuum extractor must not be used under any circumstances. In such cases, they would prefer to have a cesarean section if necessary.
Some women are afraid of significant tears and injuries (to the mother), while others are concerned about potential harm to the baby. Of course, some are afraid of both outcomes.
How does the vacuum extraction procedure work in practical terms?
This is what LÖF (Patient Insurance) wrote in 2017, and these are the rules that are still in use:
Method
Use the Vacuum Extraction Checklist.
Convert the bed to a short bed and use leg supports.
Place the cup over the "flexion point" (3 cm in front of the posterior fontanel).
Continuous CTG monitoring is sought. The responsible midwife or assisting midwife is responsible for monitoring fetal sounds.
The initial pressure is set to 0.2 kg/cm2. Ensure that there is clearance around the cup edge, then reduce the pressure to 0.8 kg/cm2.
The thumb of the free hand is placed on the cup, and the index finger is placed on the fetal head under the symphysis to ensure that the head follows during extraction. Maintain slight traction during contractions to prevent the baby from slipping back.
Pull downward in the direction of the pelvic axis during active pushing.
Perineal protection is mandatory and is performed by the operator or midwife.
The target is for the patient to be delivered within 15 minutes.
Abort the extraction and consider conversion to a cesarean section if:
Two cup releases occur.
The fetal head does not follow during extraction.
The fetal head is not at the pelvic floor after three contractions.
After a maximum of six extractions.
The woman is not expected to deliver within 15 (–20) minutes, including the application time.
It is often said that vacuum extraction is a gentler alternative to a cesarean section or forceps delivery. The method is considered safe when performed correctly by trained personnel.
Today, it is recommended that we always have a "Time-out" before a vacuum extraction delivery. This is when everyone in the room presents their roles, which helps calm the atmosphere in the delivery room.
If a vacuum extractor is used, the woman must lie on her back with her legs in leg supports at a 90-degree angle. This is to ensure the best access. If the amniotic sac has not ruptured, it is punctured first.
Some women experience discomfort when the cup is inserted into the vagina. Sometimes, it feels better if the woman breathes in some nitrous oxide while the cup is being positioned. The cup is placed on its "edge" to minimize space when trying to position it. The cup is then positioned about 3 centimeters in front of the baby's posterior fontanel, and traction is applied parallel to the contractions.
The traction is directed in line with the birth canal. At the same time, something called perineal protection is maintained, which involves using a hand to protect the perineum to minimize the risk of significant tearing.
The introduction of the "Time-out" ensures that the midwife and doctor jointly make a plan for who does what. This includes who holds the perineal protection and who delivers.
It also happens that the vacuum extractor is removed when there is one or two contractions left before the baby is born. The baby has then been helped down to the pelvic floor, and the mother can then deliver the baby's body without the assistance of the vacuum extractor. This is called tractive extraction.
If it is more urgent, or if the mother cannot push, the vacuum extractor is removed when the head has descended, and the baby's body can be delivered.
Is there anything that can be done to improve the management and reduce the risks of an instrumental delivery?
An innovation that was worked on extensively at Huddinge Hospital a few years ago was the development of a high-tech handle for use with the vacuum extractor.
The path to this innovation went through Genit: a high-tech assistive system where they tried to register the force used, the number of pulls, and the angle of use.
The information was then wirelessly sent for storage and processing. However, I haven't heard anything about the project in a while, and I wonder if it continued or if it disappeared like so much other clinical research did during the pandemic.
Perineal protection and episiotomy
As I described above, we always use what is called perineal protection during an instrumental delivery to prevent significant tearing in the mother.
Today, during a vacuum extraction, someone else (the midwife, perhaps?) often holds the perineal protection while the doctor operates the cup. However, I always hold this protection myself and have always done so. I was taught this way, and I have placed many cups over the years.
I find it very difficult to understand how you can apply and adjust the force during this manual work if you do not feel how the fetal head is moving forward. Placing a vacuum extractor is not just about pulling; sometimes it requires maneuvering the baby more delicately rather than pulling frantically.
In the case of vacuum extraction in a primiparous woman, it should always be considered to perform an episiotomy because there is evidence that it can reduce the rate of severe tears. It is important not to perform the episiotomy too early but when the baby is well visible in the vulva since the tissues are then stretched and less blood-filled.
Perform the episiotomy during a contraction. If the episiotomy is done too early, the risk of bleeding from the incision area increases.
Is vacuum extraction dangerous? The most common complications for women
Even if perineal protection is used, vacuum extraction is a situation with the risk of significant tears. Grade three and four tears are more common in instrumental deliveries than in spontaneous vaginal deliveries.
I just want to remind you of how we grade tears:
Tear Grade
Grade 1 = Skin or mucous membrane
Grade 2 = Perineal muscle but not the anal muscle
Grade 3 = Perineal muscle and anal muscle
Grade 4 = Perineal muscle, anal muscle, and the rectal wall
This was the SBU's finding in 2016, and it's still roughly as important today:
The percentage of (undetected) sphincter injuries is assumed to decrease
If ultrasound is used as an examination method immediately after delivery (which is not the current clinical practice)
When healthcare professionals have participated in training programs aimed at not rushing the baby's delivery (significant training efforts have been made, at least at our hospital)
Protecting the perineum through various techniques (training efforts have been made)
Performing episiotomies when necessary (such as the EVA study, where we await results)
However, the studies conducted so far cannot determine which of these components has the most significant impact.
Complications in the baby during an instrumental delivery
The most serious risks and complications with vacuum extraction for the baby are:
Intracranial bleeding: Bleeding inside the skull, extensive bleeding in the brain, and the spaces around the tough membrane and the arachnoid membrane.
Cephalohematoma: Swelling in the baby's head that occurs after bleeding beneath the periosteum. This swelling can be soft or firm and often appears on the side or rear part of the head, clearly limited to the skull bone. Cephalohematomas occur in about 1% of all newborns, especially after an instrumental delivery. Most cephalohematomas resolve spontaneously within a few weeks to months and typically do not require treatment.
Subgaleal bleeding: A mushy swelling that spreads diffusely over the baby's head. It occurs after a traumatic birth, where the veins between the periosteum and the scalp are torn, causing a seeping bleed.
Subgaleal hematomas are rare, affecting approximately 1-5 per thousand births but can contain up to 50-100ml of blood. Considering that a baby does not have a large blood volume, this can lead to the baby having a low blood count.
Symptoms of blood loss can include rapid heartbeat, paleness, and sometimes jaundice. This condition is potentially life-threatening and needs to be detected and referred early for monitoring and treatment.
The risk of these fetal complications is somewhat higher:
In short women with large babies
In older mothers
During induction
When an epidural (EDA) is used
Other complications with vacuum extraction include temporary swelling on the baby's head/scalp (fetal edema). This usually resolves within 2 hours to 2 weeks.
The baby may have head pain after an instrumental delivery and may need pain relief for a few days.
The baby may also experience bleeding from the eye's retina. This occurs relatively frequently during instrumental deliveries but typically has no long-term consequences.
Long-term effects on the baby?
(Ahlberg M, Ekéus C, Hjern A. Birth by vacuum extraction delivery and school performance at 16 years of age. Am J Obstet Gynecol. 2014;210:361 e1-8.)
I have a close researcher friend (Cecilia Ekeus, a professor at Uppsala University). Cecilia and her research group have conducted several studies looking at both short-term and long-term outcomes after vacuum extraction deliveries.
Is it dangerous for the baby to be born with a vacuum extractor?
In one of her doctoral students' theses, the following summary was published:
The aim was to study whether delivery with a vacuum extractor affected the child's cognitive development in the long term.
Cognition was measured in terms of performance on the national mathematics exam and the overall final grade in ninth grade.
All children born between 1990-1993 in a head-first position without any serious malformations and born after the 33rd week of pregnancy were identified in the Medical Birth Register.
The final study population consisted of 126,032 children, grouped based on the method of delivery. All of these children were then followed up in registers containing information on basic school grades.
Children delivered with a vacuum extractor had statistically significantly lower mean grades in mathematics and merit values in ninth grade compared to children born entirely naturally.
However, the differences were small: 0.51 points lower in mathematics grades (average 40.2) and 1.05 points lower in merit values (average 223.8).
Children delivered by emergency cesarean section also had slightly lower grades compared to children born spontaneously vaginally (mathematics - 0.51 and merit value - 1.20).
Since these children, delivered in different ways, had lower grades than children born through spontaneous vaginal delivery, this suggests that the cause of the choice of delivery method is more likely to be responsible for this decrease in grades rather than the method itself.
Moreover, this marginal grade reduction is considered to be so small that it is unlikely to affect the child's future cognitive abilities.
Did this answer the question of whether vacuum extraction is dangerous for the baby? Not really.
Should I continue to note in the woman's medical record that she does not want vacuum extraction? Yes, the woman decides.
As usual, however, a spontaneous vaginal delivery is always the best option! /Dr. Eva
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