2. Description
• It is an instrumental device designed to assist
delivery by creating a vacuum (negative
pressure) between itself and the fetal scalp.
3. Parts
• Suction cup of variable sizes (30, 40, 50, 60
mm). It is either metallic, or soft (made of
silicone.)
• Vacuum generator.
• Traction tubing.
4. Types
• Malmstrom cup
– A metal cup to its centre attached a metal chain
passed through the rubber tube. The other end of the
chain is attached to a handle for traction.
• Bird’s cup
– The suction rubber tube is attached to the periphery
of the cup while the handle of traction is attached by
a separate short metal chain to the centre of the cup.
• Soft cup
– It is a bell-shaped 6.5 cm diameter soft cup which is
made of a firm but supple silastic material.
9. Soft Cup
• Advantage: It produces symmetric, less
cosmetically alarming caput succedaneum and
less scalp abrasions.
• Disadvantage: It slips more than the metal cup
but with less scalp injuries.
10. Indications
• Maternal distress in 2nd stage of labour.
• Fetal distress in 2nd stage of labour.
• Prolonged 2nd stage.
• To shorten the 2nd stage in VBAC.
• For prophylactic use in mothers with
cardiovascular, respiratory, cerebrovascular
disorders.
12. Prerequisites
• Bladder must be emptied
• Cervix fully dilated
• No evidence of CPD
• Vertex presentation and not above the station
of +2
• Membranes must be ruptured
13. Technique
• APPLICATION
– Station of the head and its position is assessed
– Instrument is checked to be in working condition
before application
– Selection of the cup is important
– The cup is introduced after retraction of perineum
with two fingers of the other hand
14. – The center of the cup
should be on the flexion
point of the head, which is
a point located on the
sagittal suture, 3cm in front
of posterior fontanelle
– Traction at this point results
in maximum flexion (flexing
median application)
16. Technique
• NEGATIVE PRESSURE
– The vacuum is created gradually after ensuring that no
soft tissue is included in the cup.
– Once the pressure reaches 0.2kg/cm2, it is rechecked
for inclusion of the soft tissue in the cup.
– The negative pressure is then gradually increased to a
maximum of 0.8kg/cm2 to create a chignon (artificial
caput)
– Following this the traction is applied
17. • Traction should be synchronous with uterine contraction
• Direction of pull should follow curve of Carus
• Traction should be at right angle to the cup
Principles During Traction
18. Principles During Traction
• Counter pressure should
be applied with the left
hand (thumb on the cup,
index finger on the scalp)
to prevent slipping
• Descent should occur
with each pull
• Delivery should occur
within 3 pulls over a
period of 15 minutes
19. Principles During Traction
• If the cup slips, reevaluate the station and
position of the head and reassess the pelvis
• Reapply only when there is no problem
• If it slips again or descent is not satisfactory, the
procedure should be abandoned
• As soon as baby is delivered, the vacuum
pressure is reduced, and cup is detached
• Delivery is completed in the normal way
24. Comparison
Forceps Delivery Vacuum Delivery
Does not require maternal effort Require some maternal effort as need to
synchronize with uterine contraction
Equipment less complex Less expertise required
Less incidences of cephalhematoma More incidences of cephalhematoma
Can be used in preterm Cannot be used in preterm
Can be used in non-cephalic
presentations
Can be used in partially-rotated head. Not
used in non-cephalic presentations.
Less injuries to infant, higher morbidity
for mother
Less maternal injuries, higher morbidity
for infant
Need for anesthesia/analgesia No need for anesthesia
Takes less time in fetal distress, quicker
delivery
Higher failure rate
