🔘 Forceps Delivery

Forceps delivery:

👉🏻 Definition:

• Obstetric forceps is a pair of instruments specially designed to assist extraction of the foetal head and thereby accomplishing delivery of the foetus.

👉🏻 Introduction of Forceps:

• Only three varieties are commonly used in present day obstetric practice.

• These are:-

1. Long-curved forceps with or without axis traction device

2. Short-curved forceps

3. Kielland’s forceps

• The basic construction of these forceps is the same in that each consists of two halves (blades) articulated by a lock.

• In India, Das’s variety is commonly used with advantages.

👉🏻 Parts: 

i) Blades - There are two blades and are named right or left in to relation to maternal pelvis in which they lie when applied.

ii) Shank

iii) Lock

iv) Handle with or without screw

👉🏻 Types of forceps:

1. Long curved Obstetric Forceps:

• Measurements - Length is 37 cm, distance in between the tips is 2.5 cm and widest diameter between the blades is 9cm.

i) Blade:

• The blade is fenestrated to facilitate a good grip of the foetal head. - There is usually a slot in the lower part of the fenestrum of the blades to allow the upper end of the axis traction rod to be fitted.

• The toe of the blade refers to the tip and the heel to the end of the blade that is attached to the shank.

• The blade has got two curves:

a. Pelvic curve:

• The curve on the edge is to fit more or less the curve on the axis of the birth canal (curve of Carus).

• The front of the forceps is the concave side of the pelvic curve. Pelvic curve permits ease of application along the maternal pelvic axis.

b. Cephalic curve:

• It is the curve on the flat surface which when articulated grasps the foetal head without compression.

ii) Shank:

• It is the part between the blade and the lock and usually measures 6.25 cm.

• It increases the length of the instrument and thereby, facilitates locking of the blades outside the vulva.

iii) Lock:

• The common method of articulation consists of a socket system located on the shank at its junction with the handle (English lock). 

• Such type of lock requires introduction of the left blade first.

iv) Handle:

• The handles are apposed when the blades are articulated. It measures 12.5 cm.

• There is a finger guard on which a finger can be placed during traction. A screw may be attached usually at the end (or at the base) of one blade (commonly left). 

• It helps to keep the blades in position

2. Short curved obstetric forceps:

• The instrument is lighter, about a third of the weight of a long curved forceps.

• It is short which is due to reduction in length of the shank and handles.

• It has a marked cephalic curve with a slight pelvic curve.

3. Kielland’s Forceps:

• It is a long almost straight (very slight pelvic curve) obstetric forceps without any axis traction device.

• It has got a sliding lock which facilitates correction of the head. 

• One small knob on each blade is directed towards the occiput.

👉🏻 Classification of forceps operation:

1. Outlet Forceps:

• Scalp is visible at the introitus without separating the labia

• Foetal skull has reached the level of the pelvic floor

• Sagittal suture is in direct anteroposterior diameter or in the right or left occiput anterior or posterior position.

• Foetal head is at or on the perineum. (Wrigley forceps)

2. Low forceps:

• Leading point of the foetal skull (station) is at +2 cm or more but has not yet reached the pelvic floor.

3. Mid forceps:

• Foetal head is engaged

• Leading point of the foetal skull (station) is above +2 cm (Kielland's forceps)

👉🏻 Classification of forceps operation:

1. Outlet Forceps:

• Scalp is visible at the introitus without separating the labia

• Foetal skull has reached the level of the pelvic floor

• Sagittal suture is in direct anteroposterior diameter or in the right or left occiput anterior or posterior position.

• Foetal head is at or on the perineum. (Wrigley forceps)

2. Low forceps:

• Leading point of the foetal skull (station) is at +2 cm or more but has not yet reached the pelvic floor.

3. Mid forceps:

• Foetal head is engaged

• Leading point of the foetal skull (station) is above +2 cm (Kielland's forceps).

👉🏻 Indications:

• Delay in the 2nd stage.

a. Maternal:

• Maternal distress

• Pre-eclampsia

• eclampsia

• Heart disease 

• Post caesarean pregnancy

• Failure to bear down

b. Foetal:

• After coming head of breech.

• Prolonged second stage of labour

👉🏻 Prerequisites for vaginal operative delivery:

• The cervix must be fully dilated and effaced.

• Membranes must be ruptured.

• The head must be engaged with no parts of head palpable abdominally.

• Head position is exactly known

• No appreciable CPD

• The bladder must be empty

• Presence of good uterine contractions as a safeguard to postpartum haemorrhage

• Adequate maternal analgesia

• Informed consent with prior clear explanation

1) Low forceps operation:

• The women’s vulval area is thoroughly cleaned and draped with sterile towels using aseptic technique. 

• The bladder is emptied using a straight catheter.

• A vaginal examination is performed by the obstetrician to confirm the station and exact position of the foetal head

• A pudendal block, supplemented by perineal and labial infiltration with 1 % lignocaine hydrochloride, is given to produce effective local anaesthesia.

• An episiotomy may be done prior to introduction of the blades or during traction when the perineum becomes bulged and thinned out by the advanced head.

• The forceps are identified as left or right by assembling them briefly before proceeding.

Step 1- Identification and application of the blade:

• The left blade is passed gently between the perineum and foetal head with the four fingers of right hand of the operator’s hand lying alongside the foetal head protecting the maternal tissue. 

• The handle of the left blade is taken lightly by three fingers of left hand.

• The blade is introduced between the guiding internal fingers and foetal head, manipulated by the thumb.

• When correctly applied, the blade should be over the parietal eminence, the shank should be in contact with perineum and superior surface of the handle should be directed upwards.

• The procedure is repeated with the right blade until it sits on the right of the pelvis.

Step 2 - Locking of the blade:

• It should then be easy to lock the two blades and there should be little or no gap between the handles.

• A significant gap suggests that the forceps are wrongly positioned and they should be reapplied after carefully checking the position of head.

• Correct application is evidenced by:

a. Easy locking

b. The blades are equidistant from the lamboid suture

c. Firm gripping of the head on the biparital diameter.

Step 3-4 - Traction and removal of blades:

• Principle: Steady but intermitted traction should be given if possible during contraction.

• In outlet forceps the pull may be continuous.

• Gripping the articulated forceps during traction: the traction is given by gripping the handle, placing the middle finger in between the shanks with ring and right fingers on either side on the fingers guard.

• During the final stage of traction, the four fingers are placed in between shank and thumb which is placed on the under surface of the handles and exerts the necessary force.

• Direction of the pull: corresponds to the axis of the birth canal.

• Downward n backward - until the head comes to the perineum. 

• Horizontally straight toward the operator till the head almost crowned - Upward and forward, toward the mother’s abdomen to deliver the head by extension.

• Blades are removed one after another, right one first.

• Following the birth of the head, usual procedure are to be taken as normal delivery.

• IV methergin 0.2 mg is administered with the delivery of the anterior shoulder.

• Episiotomy is repaired.

2) Outlet forceps operation:

• Wringley’s (short curved) forceps are used exclusively in outlet forceps operation.

• Local anaesthesia with1% lignocaine.

• The blades are introduced as in the low forceps operation with long curved forceps except that two fingers are to be introduced into the vagina for application of the left blade.

• Traction is given indirection of the pull is straight horizontal and then upward and forwards.

3) Mid forceps operation:

• The commonest indication of mid forceps operation is following manual rotation of the head in mal rotated occipito-posterior position.

• Commonly used – long curved forceps

• Kielland’s forceps is useful.

Procedure:

• General anaesthesia is preferable.

• Prior correction of the malrotation then introduction of the blades.

A) Without axis – traction device:

• Blades introduce as low forceps. An assistant is required to hold the left handle after its introduction.

• Traction- Downward n backward- Horizontally straight - Upward and forward.

B) With axis – traction device:

• During introduction of the right blade, the traction rod must be held forward otherwise it will prevent locking of the blades. 

• Traction during raction, the traction rods should remain parallel with the shanks. When the base of the occiput comes under the symphysis pubis, the traction rods are to be removed.

👉🏻 Complication of forceps operation:

1. In the mother:

a. Immediate:

• Injury

• Extension of the episiotomy towards rectum or upwards up to the vault of vagina

• Vaginal lacerations

• Cervical tear especially when applied through an incompletely dilated cervix.

• Bruising and trauma to the urethra

• Postpartum haemorrhage due to trauma, or atonic uterus related to prolonged labour or effects of anaesthesia.

• Shock due to blood loss, prolonged labour and dehydration.

• Sepsis due to devitalisation of local tissues and improper asepsis.

b. Late:

• Chronic low backache due to tension imposed on softened ligaments of lumbosacral or sacroiliac joints during lithotomy position.

• Genital prolapse or stress incontinence.

2. In the infant:

a. Immediate:

• Asphyxia due to intracranial stress out of prolonged compression.

• Intracranial haemorrhage due to misapplication of the blades.

• Cephalhaematoma

• Facial palsy due to damage to facial nerve.

• Abrasions on the soft tissues of the face and forehead by the forceps blade

• Skull fractures, cervical spine injury.

b. Remote:

• Cerebral or spastic palsy