Obstetrics and Gynecology - A.M. Hromova 2000

Operative Obstetrics
Delivery Operations
Vacuum Extraction of the Fetus

This method is used when rapid delivery is required, a Cesarean Section is undesirable or contraindicated, and conditions for forceps application are absent.

The vacuum extractor consists of a vacuum unit (which generates negative pressure) and cups applied to the fetal HEAD. The operating principle is based on creating negative pressure between the inner surface of the cup and the fetal head. This generates an attractive force that enables the traction required to deliver the fetus.

Indications for vacuum extraction of the fetus:

- prolonged uterine inertia;

- onset of Fetal Hypoxia;

- umbilical cord prolapse (after repositioning);

- partial placental Separation;

- bleeding from the marginal sinus of the Placenta.

Contraindications include the following conditions:

- deflexion presentations of the fetus;

- premature labor at less than 35 weeks of gestation;

- cephalopelvic disproportion;

- conditions where pushing is undesirable (Heart defects, severe forms of gestosis, etc.);

- Hydrocephalus of the fetus;

- anomalies of head engagement;

- premature placental abruption;

Prerequisites:

- living fetus;

- ruptured amniotic membranes;

- full Cervical Dilatation;

- adequate cephalopelvic proportions;

- vertex presentation of the fetus.

Surgical technique. The cup is guided along the palmar surface of the fingers of the right hand, while the vaginal introitus is opened with the fingers of the left hand. The cup is inserted sideways into the straight diameter, rotated into the transverse diameter, and its opening is applied against the fetal head. The fontanelle is the preferred site (where the scalp firmly adheres to the periosteum). A negative pressure of 500-550 mmHg is established. The correct placement of the cup on the head must be verified (trapping of the vaginal walls must be ruled out). Tractions are performed synchronously with uterine contractions along the axis perpendicular to the plane of the cup opening. The traction force must not exceed 10-15 kg (the force exerted by the obstetrician's arm bent at the elbow).

Vacuum extraction is rarely used nowadays due to the potential Adverse effects of this intervention on the child's subsequent neuropsychological development.

Control questions

1. What are the components of a vacuum extractor?

2. Operating principle of the vacuum extractor.

3. Indications for vacuum extraction.

4. Contraindications for vacuum extraction.

5. Technique of fetal vacuum extraction.