Suction cup delivery (vacuum extraction, VE; synonyms: vacuum delivery; suction cup birth) is an obstetric surgical procedure used to assist vaginal birth (birth through the vagina). The vacuum extractor is an obstetric device used to terminate birth from the cranial position (SL) during the expulsion period. Various attempts to use a vacuum to end childbirth have been made in different variations since 1705. They were usually not very successful, so forceps extraction was preferred. It was not until 1954 that the Swede Malmström succeeded in developing a metal bell by means of a concave suction mechanism that the method gained acceptance. In Germany, this method was introduced in 1955 by Evelbauer (Braunschweig). The original bell developed was a metal bell. In the meantime, there have been developments in silicone (soft and hard), rubber bells as well as a disposable instrument. The differences will not be discussed here.
Indications (areas of application) [1, 2, 4, Guideline 1]
Birth termination from cranial position in the expulsion period due to subsequent indications:
- Mother
- Child
Contraindications [1, 2, 4, Guideline 1]
- Suspected disproportion
- Height level: above the interspinous level (IE; results from the line connecting the two spinae ischiadicae/seat bone spine) at occipital setting.
- Guiding point between the interspinal plane and the pelvic floor in the case of transverse arrow suture or deflexion posture (most of the head circumference has not yet entered the pelvis in this situation).
- <36th week of pregnancy (SSW) because of the potential risk of intracranial hemorrhage (brain hemorrhage) due to the immaturity of the child.
Prerequisites [1, 2, 4, Guideline 1]
- Accurate altitude diagnostics
- Exclusion of contraindications (contraindications).
- Empty urinary bladder, so as not to interfere with deep treading of the fetal head and to prevent maternal injury.
The surgical procedure
Instrumentation
Components are:
- Bell, either metal, silicone, or rubber; offered in various orifice diameters.
- Hose system that connects to the vacuum-generating system.
- Vacuum system: different systems are offered, e.g. electric system with vacuum bottle and vacuum pump, manual system with manual generation of negative pressure.
Technology
- Insertion of the bell: this is inserted into the vagina over the edge, rotated 90° and placed on the child’s head.
- Attachment of the bell: The attachment is made in the area of the guide line in the guide line.
- In the case of anterior occipital position: in the area of the small fontanel.
- In the case of anterior occipital position: in the area of the large fontanel
- Creation of the vacuum: The vacuum should be created slowly, preferably over a period of 2 minutes. During suction, the correct fit is checked to exclude entrapment of maternal soft tissues.
- Trial traction: it is checked whether the head steps deeper during traction.
- Extraction: it is carried out in synchrony with the contractions in the line of guidance with simultaneous co-pushing of the delivery, usually assisted by the Kristeller handle (method by which the birth of the child should or can be accelerated by synchronous pressure on the uterine roof in the expulsion phase). When the contraction subsides, the traction decreases and sists during the pause in labor. One hand is the “traction hand”, the other is the control hand (checks, in addition to the bell, the lowering and, if necessary, changes in the rotation of the head). In case of a pull not exactly in the leading line or a misjudgment of the bell, it draws air. This is the signal to immediately change the direction of the pull.Tearing off should be avoided if possible because it can lead to sudden and pronounced intracranial pressure fluctuations in the child (risk of intracranial hemorrhage/brain hemorrhage). It may also cause skin abrasions on the child’s head. If necessary, a second application of the bell is possible.
- Development of the head: during the “cutting of the head”, i.e. when the head is visible in the vulva/external area of the female primary sex organs (between the large labia/pubic lips) even during the pause in labor, i.e. remains stationary, the surgeon steps to one side of the woman giving birth and performs perineal protection with the contact hand. After development of the head, the negative pressure is turned off. The bell can then be easily removed.Note: “Incision of the head” means: the head appears in the vulva during the contraction and retracts into the vagina at the end of the contraction.
Possible complications [1-5, Guideline 1]
Child
Complications in children depend on the duration of vacuum extraction, frequency of traction, tearing, and reapplication.
- Tearing off the bell
- Severe abrasions and lacerations (lacerations or cuts) on the child’s head. They develop with long extraction duration, continuous traction, and when the bell is torn off. In all cases, regression and healing occur without problems.
- Artificial caput succedaneum (birth tumor), so-called chignon. This is an accumulation of bloody-serous fluid in the subcutis (subcutaneous tissue) and cutis, has a diffuse spread across the cranial sutures, is doughy edematous (edema-like; swelling), about 5-6 cm spreading and passing over the cranial sutures. A ring hematoma (“ring-like effusion”) through the bell is characteristic. This distinguishes the chignon from the spontaneous birth tumor regardless of size. Regression usually within 12-24 hours.
- Cephalhematoma (head hematoma): this is a subperiosteal hematoma (bruise below the periosteum/periosteum) and results from rupture of vessels between the periosteum and bone due to shear forces. Because the periosteum is firmly fused to the bone at the cranial sutures, it does not cross the cranial sutures (unlike subgaleal hemorrhage, see below). Because of the confinement, blood loss is limited and has no clinical relevance. In most cases, the hematoma resorbs within a few days. However, in the case of pronounced findings, it may sometimes take several weeks. It occurs up to 12% of all vacuum deliveries (2% in spontaneous deliveries, 3-4% in forcep deliveries/forceps deliveries).
- Intracranial hemorrhage (cerebral hemorrhage): causes: multiple rupture of the bell (> 2 times). The resulting intracranial pressure fluctuations, which may be as high as 50 mmHg, may be the cause of cerebral hemorrhage; other causes include prolonged extractions (> 15 minutes) and frequent extractions (> 6 times).
- Subgaleal hemorrhage (subgaleal hematoma): subgaleal hemorrhage occurs between the periosteum (periosteum) and galea aponeurotica (muscle aponeurosis) due to detachment of the aponeurosis from the periosteum and bleeding into this anatomically preformed space. It may extend to the anatomic margins of the aponeurosis and is a potentially life-threatening complication of vacuum extraction. Unlike cephalhematoma, blood loss is not limited by cranial sutures. Up to 80% of the infant’s blood volume can bleed in, leading to hypovolemic shock (shock due to lack of volume). This complication occasionally occurs after hours or days. The incidence (frequency of occurrence) is reported to be 1-4% (about 0.4/1000 in spontaneous delivery). The mortality rate can be as high as 25%. Commonly, these complications occur when the suction cup is placed in the area of the large fontanel, when slipping, as well as during long extraction attempts.
- Retinal hemorrhage (retinal hemorrhage): retinal hemorrhages occur more frequently after vacuum extraction as well as after forceps deliveries (forceps deliveries) than after spontaneous deliveries. They are harmless and regress spontaneously within 4 weeks without ophthalmologic follow-up. Permanent visual disturbances do not occur.
- Hyperbilirubinemia (increased occurrence of bilirubin in the blood): hyperbilirubinemias occur more frequently after vacuum extraction than after forceps surgery. Phototherapeutic treatment is occasionally necessary.
Mother
- Vaginal rupture
- Labia injury (injury of the labia)
- Perineal laceration
- Episiotomy (perineal incision)
- Heavy bleeding
Vacuum or forceps?
The incidence of vaginal operative deliveries is 6% of all births [Guideline 1], of which about 5.9% are vacuum extractions and about 0.3% are forceps (forceps) deliveries. The long observed downward trend in forceps extractions continues. From the publications, it can be seen that there are no recommendations as to whether vacuum extraction or forceps delivery is more beneficial. Often, the application also depends on the experience of the obstetrician in this method. Both methods have advantages and disadvantages. Disadvantages of vacuum extraction are fetal injuries in the area of the suction point of the vacuum extractor, abrasions, lacerations, accidental caput succedaneum, cephalhematoma, subgaleal hemorrhage (they are more frequent in vacuum extraction with the metal bell, less frequently with soft bells, in which again tearing is more frequent). Disadvantages of forceps extraction (delivery in which the baby is extracted through forceps applied to the head) include more difficult handling and increased risk of injury to maternal soft tissues.
