Alternative to forceps for extraction of an infant from the birth canal, if it becomes stuck during delivery.
Ventouse extraction works by placing a cup of 30 - 60 mm diameter on the top of the infant's head when it is accessible in the birth canal. The cup is attached to a vacuum extractor, which creates sufficient suction (about 0.8 kg/cm2) for the cup to grip the head. The baby can then be gently pulled out by a chain attached to the cup.
The ventouse apparatus was developed in the 1950's by Mälmstrom, and has been refined since then. There are three types of cup
- the Mälmstrom cup, made of metal, with the pulling chain passing through the rubber suction tube
- Bird's cup, also metal, where the suction tube is separate from the traction chain
- a soft cup, made of silicone, which can be used for extraction during earlier stages of labour
The ventouse apparatus is less damaging, and less traumatic, to the mother and the baby than forceps. However, it is not suitable for breech babies. It is occasionally used in Caesarian sections, and should only be performed by trained medical staff.