Instrumental vaginal delivery :Delivery of a baby
vaginally using an instrument for assistance.
The incidence of instrumental intervention
varies widely both within and between countries
and may be performed as infrequently as 1.5%,
or as often as 26%.
Fetal distress –
Altered fetal heart rate and rhythm / by passage of
Objective evidence-Abnormal CTG and fetal
Inadequate expulsive efforts
Prolonged second stage – More than 2 hrs without and more
than 3 hrs with regional anaesthesia
in a nulliparous woman.
More than 2hrs with and more
than 1 hr without regional
anaesthesia in parous women.
Previous caesarean section or genital prolapse repair.
Medical indications to cut short second stage -
Cardiac disease NYHA class III or IV
Severe pre-eclampsia, eclampsia.
Uncorrected cerebral vascular malformations.
Spinal cord injury
Ventouse is an instrumental device designed to
assist delivery by creating a vacuum between it
and the fetal scalp that creates an artificial caput or
chignon within the cup that holds firmly and
allows adequate traction.
In the United states the device is referred as
vacuum extractor , while in Europe it is commonly
referred as a Ventouse.
James Yonge (1740) , a navy surgeon tried to assist delivery
by using a cupping glass fitted to the fetal scalp combined
with an air pump.
James Simpson , (1840) a professor of midwifery in Edinburg
is often credited with the invention of first vacuum extractor.
Malmstrom (1954) introduced the vacuum extractor which
has been widely accepted.
Bird (1969) modified the cup by separating the traction device
from the suction tubing allowing improved traction and
preventing slippage of the cup.
TYPES OF VACUUM CUPS-
Semirigid-Made of flexible plastic
Soft – Made of silicon.
Kiwi Omnicup – Made of rigid plastic.
SIZES AVAILABLE- The cups come in different sizes
and are usually 4,5 or 6 cm in diameter.
The presentation should be cephalic and
preferably well flexed.
Membranes must be ruptured.
No evidence of major cephalopelvic
Cervical dilatation must be sufficient to admit
the cup. The larger cup is safer and more
Head well engaged . In present day practice ,
delivery of the fetal head from high stations, i.e
above +2 is no longer favoured except in the case
of second twin.
Obstetrician is well trained in the application
of the instrument.
The patient is placed in lithotomy position.
Local parts are painted with antiseptic solution such as
betadine and draped with sterile sheets.
Ensure that the bladder is empty.
A thorough examination to determine the
station of the fetal head , position of the
occiput and suture lines, assessment of the
pelvis and extent of cervical dilatation made.
Pudendal block anesthesia usually suffices.
Proper cup placement is the most important
determinant of success in vacuum extraction.
• The centre
of the cup
in front of
Make sure that maternal soft parts like cervical
rim or vaginal wall are not included in the cup.
When using rigid cups vacuum is created
gradually by increasing the suction by 0.2kg/cm
sq every 2 mins until a negative pressure of
0.8kg/cm sq is reached . With soft cups negative
pressure can be increased to 0.8kg/cm sq over
as little as 1 min.
Traction should be intermittent and
coordinated with maternal expulsive
Traction may be initiated by using a
two handed technique.
Fingers of one hand are placed over
the suction cup while the other hand
grasps the handle of the instrument.
Traction should be sustained during
the pains and the direction of pull
should correspond with the axis of the
birth canal .
This can be ensured by pulling at right
angle to the cup .
The higher the head the more
downward should be the direction of
The total duration of time
recommended should not exceed 20
mins as greater the time greater is the
chance of cephalhaematoma
It is recommended to avoid more than
3 applications to prevent
After determining position of the head, (A) insert the cup into the vaginal
vault, ensuring that no maternal tissues are trapped by the cup. (B) Apply the
cup to the flexion point 3 cm in front of the posterior fontanel, centering the
sagittal suture. (C) Pull during a contraction with a steady motion, keeping the
device at right angles to the plane of the cup. In occipitoposterior deliveries,
maintain the right angle if the fetal head rotates. (D) Remove the cup when the
fetal jaw is reachable
Head does not descend with each pull.
Head is undelivered after 3 pulls with no
descent or after 20 mins of operation.
The cup slips off the head with maximum
Soft tissue injuries such as cervical tears ,
annular detachment of cervix , vaginal
tears , perineal lacerations and tears ,
extension of episiotomy , vaginal wall and
Incompetent os at subsequent pregnancy.
Hypoxia , particularly when extraction has
taken a long time and has been difficult.
Injury to scalp , abrasions ,lacerations and
haemorrhage , intraventricular and
cerebral haemorrhage particularly when the
babies are preterm.
Shoulder dystocia ,particularly when
the baby is macrosomic.
Prolonged traction in preterm babies
may lead to neurological sequel.
Premature babies , less than 34 wks
of gestational maturity.
Major degree of cephalopelvic
Soft tissue obstruction in the pelvis.
Breech and face or non vertex
High station of the head , above
Suspected fetal coagulopathy.
Scalp electrode has been used or
fetal scalp blood sampling
Obstetric forceps is a pair of
instruments specially designed to
assist extraction of fetal head or to
overcome or correct certain
abnormalities in cephalopelvic
relationship that interfere with
progress of labor and thereby
accomplishing delivery of fetus.
In modern obstetrics , all difficult forceps
delivery, the high and midcavity forceps ,
the axis traction forceps etc. are all
obsolete because of the high morbidity and
mortality these instruments cause to both
mother and fetus.
The only permissible forceps delivery today
is probably an outlet or low forceps.
5-15% depending on the
attitude of the staff, kind of
labour analgesia and parity of
The credit for the design and early use of
obstetric forceps goes to Chamberlen of
England. This instrument was kept a family
secret until Chapman publicly announced it
in the late 18th century.
Credit of introducing pelvic curve to the
earlier design goes to Levert of Paris.
Smellie gave the simple and effective design
of the secure English lock.
Tarnier is remembered for his invention of
the axis traction device. This permitted the
pull to coincide appropriately with the axis
of the pelvis at all stations.
Kjelland’s forceps was designed to permit
rotation and extraction of the baby. The
pelvic curve was minimized and offset by a
reverse pelvic at the end of the blades made
it almost a straight instrument. The sliding
lock permitted application of the forceps blades on
an asynclitic head.
Long forceps with axis
Rotation forceps Kjelland’s
Forceps for special use After coming head in
At caesarean section
At caesarean section
In India Das’s variety is most commonly
Length is 37cm.
Distance between tips is 2.5cm and widest
diameter between blades is 9cm.
Parts are Blade, Shank, lock, handle.
oBlade – Fenestrated
To facilitate good grip
To minimise compression of fetal
Decreases the weight of the
oToe – Tip of the blade.
oHeel – End of the blade that is attached to
Pelvic curve – Fit on the axis of the birth
canal (Curve of Carus). Forms a part of a
circle whose radius is 17.5cm. The front of
the forceps is the concave side of the pelvic
oCephalic curve – Curve on the flat surface which
when articulated grasps the fetal head without
compression. Radius of curve is 11.5cm.
oShank – part between the blade and lock.
oLock – Requires introduction of left blade first.
oHandle – Measures 12.5cm. Handles are
apposed when the blades are articulated.
Place the instrument in front of the pelvis with the
tip of the blades pointing upwards and the concave
side of the pelvic curve forward. The blade which
corresponds to left of maternal pelvis is the left
blade and that to the right side is right blade.
When isolated –
The tip should point upward. The cephalic curve is to
be directed inwards and the pelvic curve forwards.
Most commonly used instrument for
Long almost straight.
Absent or slight reverse pelvic curve.
Has got a sliding lock which facilitates
the correction of asynclitism of head.
One small knob in each blade is directed
Lighter about 1/3rd of the weight of an
ordinary long curved forceps. Instrument is
short due to reduction in the length of the
shanks and handle.
It has a marked cephalic curve with a slight
Wrigley’s forceps are nearly ideal outlet
forceps, light weight of length 27.5cm.
The max. distance between closed blades is
7.5 and tip of blades 2.7cm.
1 . Scalp is visible at the
introitus without separating
2.Fetal skull has reached
the pelvic floor.
3.Saggital suture in AP
diameter or right or left
occiput anterior or posterior
4.Fetal head is at or on
5.Rotation does not exceed
Low forceps Leading point of fetal
skull is at station ≥
+2 cm, and not on the
Rotation is 45 degrees
or less (LOA or ROA to
occiput anterior, and
LOP or ROP to occiput
Rotation > 45 degrees.
Station above +2 but
head is engaged.
1 – Traction- where unaided expulsive efforts of
mother are insufficient to achieve a safe delivery.
2- Rotation- KJelland’s forceps.
3 – Protection-It forms a protective cage around
the preterm head.
4 – Controlled delivery of after coming head In
breech to lessen the dangers of sudden
5-Simpson forceps- Deliver the fetus with a
moulded head as is common in nulliparous
6-Tucker-Mclane is often used for fetus with
round head as often seen in multiparous
7-Wrigley forceps can be used in cesarean
section delivery where manual traction is
Complex combination of traction ,
compression and friction by the
adjacent maternal tissue.
Force required for a Primipara – 18 kg.
Multipara – 13 kg.
Presentation should be either occipitoanterior
or direct occipitoposterior.
Fully dilated cervix.
Membranes already ruptured.
Bladder and bowel must be empty.
There must be no major disproportion at
Uterus must be actively contracting and
Head must be at perineum , rotated anteriorly
such that occiput lies near or just under the
symphisis pubis in occipito anterior position.
The sagittal suture must lie in the anterior
posterior diameter of the pelvis.
Head should lie at station +2 to +4.
Cephalic application – The blades are applied
along the side of the head grasping the
biparietal diameter in between the widest part
of the blades. The long axis of the blades
corresponds to the occipito-mental plane of
the fetal head.
Ideal method of application as it has got a
negligible compression effect on the cranium.
Biparietal-bimalar application offers uniform grip on the
two sides. The sagittal suture bisects the shank which is
over the flexion point – about 3 cm anterior to the
Pelvic application – When the blades of the
forceps are applied on the lateral pelvic walls
ignoring the position of the head, it is called
pelvic application. If the head remains
unrotated ,this type of application puts
serious compression effect on the cranium
and thus must be avoided.
1 -Patient is taken in dorsal
lithotomy position and
positioned such that
her buttocks are at the
age of the table.
block with perineal
infiltration is provided.
3- The left blade is held
vertically in the left
hand over the
Two fingers of the right
hand are slipped
alongside the fetal
head holding the
vaginal tissues back .
4-The blade is then
introduced into the
left side of the
maternal pelvis under
the guidance of right
The blade is closely
applied to the fetal
head , gently guided
by the right fingers to
sit on the lateral side
of the fetal head over
the baby’s ear.
• 5-The fingers of left
hand are next slipped
along the other side of
the fetal head and the
right blade is glided
along its palmar
aspect to the right side
of the maternal pelvis.
Biparietal-bimalar application offers uniform
grip on the two sides. The sagittal suture
bisects the shank which is over the flexion
point – about 3 cm anterior to the occiput.
6 –When correctly
biparietal placement) the
blades are articulated with
7-Traction is in the
direction of the
pelvic curve and is
8-An episiotomy is usually needed when the head is
crowning at the vulva.
9- In low forceps the direction of traction is
initially downwards and backwards till the
occiput comes under the symphysis pubis then
directed horizontally straight towards operator
till the head is almost crowned.
The direction of pull
is gradually changed upward and forward pull
towards the mothers abdomen to deliver the
head by extension.
In outlet forceps the direction of pull is straight
horizontal and then upwards and forwards.
10-The right blade is removed first and then the
11-IN OCCIPUTO-POSTERIOR POSITION –
Traction is given horizontal till the root of
nose is under the symphysis pubis then
upward till the occiput emerges over the
perineum and finally downwards to deliver
nose and chin.
12- IN FACE PRESENTATION – Blades
are introduced along the occipito-
Traction is applied downwards till the
chin appears below symphysis pubis
and then upward delivering nose ,
eyes , brows and occiput.
Forceps used are – Long curved with or
without axis traction device & Kjelland’s
INDICATION – Following manual rotation in
Blades are to be introduced only after manual
correction of malposition of occiput.
Can be applied in DTA / face presentation, or
correction of asynclitism.
Application- Anterior blade is applied first
followed by posterior blade.
Wandering method in DTA – Anterior blade is
applied over the face then moved over to
anterior parietal bone. The posterior blade is
applied between head and sacrum.
Blades can also be applied directly over the
Named after De Lee.
Refers to forceps delivery only to shorten
second stage of labour when maternal and/or
fetal complications are anticipated.
Previous H/O caesarean section
To curtail the painful second stage
Patient under epidural analgesia
It is a tentative attempt of forceps delivery
in a case of suspected midpelvic contraction
with a preamble declaration of abandoning
it in favour of cesarean section if moderate
traction fails to overcome the resistance.
Conducted in OT keeping everything ready
for caesarean section.
When a deliberate attempt in vaginal delivery
with forceps has failed to expedite the
process, it is called failed forceps.
Incompletely dilated cervix
Unrotated occipito posterior positions
Unrecognised malpresentation or hydrocephalus
Clinically big baby
Maternal BMI > 30
In a case with mid-cavity delivery.
1. Greater incidence of maternal vaginal and
perineal lacerations including 3rd and 4th degree
tears compared with vacuum deliveries.
2.Perineal pain during delivery.
6.Urinary and fecal incontinence.
Can be used in unrotated or malrotated head.
Helps in autorotation.
Not a space occupying device like forceps blade.
Traction force is less(10KG) compared to forceps.
Low rates of maternal trauma and genital tract
Analgesia need is less.
Reduced maternal pelvic floor injuries and
is advocated as the instrument of first
Perineal injuries are less compared to
Postpartum maternal discomfort are less.
Simplicity of use in delivery makes it
convenient to the operator.
Where moderate traction is required,
forceps will be more effective as compared
It can quickly expedite fetal delivery in case
of fetal distress where ventouse will be
unsuitable as it takes longer time.
Safer in premature babies. The fetal head
remains inside the protective cage.
Can be employed in anterior face or in
after coming head of breech
presentation , where ventouse is
Lesser neonatal scalp trauma , retinal
haemorrhage , jaundice or
cephalohaematoma compared to
Higher rate of successful vaginal