FORCEPS DELIVERY

Obstetrical forceps are designed for extraction of the fetus. True forceps were first devised in the late 16^th and beginning of the 17^th century

Forceps

Obstetrical forceps is a pair of instruments specially designed to assist extraction of the fetal head and there by accomplishing delivery of the fetus.

History

The obstetrical forceps, allowing during birth, the extraction of a living child, was invented by the eldest son of the Chamberlen family of surgeons. The Chamberlens were French Huguenots working in Paris before they immigrated to England in 1569 to flee from religious violence perpetrated in France. William Chamberlen, the patriarch of the family, was most likely a surgeon; he had two sons, whom he both named Pierre, that became maverick surgeons that specialized in midwifery. William and the eldest son practiced in Southampton and then settled in London. The inventor was probably the eldest Pierre (then Peter in England), who became obstetrician-surgeon of Queen Henriette, wife of King Charles I of England and daughter of Henry IV, King of France. The forceps were used most notably in hard and difficult childbirths, ones which would most probably result in the death of the baby, because in other situations hooks or other instruments that would endanger the life of the infant were used. In the interest of secrecy, the forceps were carried into the birthing room in a lined box and would only be used once everyone was out of the room and the mother blindfolded. He was succeeded by his nephew, Dr. Peter Chamberlen (also known as Peter the Third), as royal obstetrician. The success of this dynasty of obstetricians with the Royal family and high nobles was related in part to the use of a "secret" instrument allowing release of live child in difficult cases.

The instrument was kept secret for a 150 years by the Chamberlen family, although there is evidence for its presence of as far back as 1634. Hughes Chamberlen, Grand nephew of Peter the eldest, tried to sell the instrument in Paris in 1670, but the demonstration he did in front of François Mauriceau, responsible for Paris Hotel-Dieu maternity, was a resounding failure which resulted in the death of child and mother. The secret may have been sold by Hughes Chamberlen to Dutch obstetricians at the start of the 18th century in Amsterdam, but there are doubts about the authenticity of what was actually provided to buyers.

Models derived from the Chamberlen instrument finally appeared gradually in England and Scotland in 1735. About 100 years after the invention of the forceps by Peter Chamberlen Sr. a surgeon by the name of Jean Palfyn presented his obstetric forceps to the Paris Academy of Sciences in 1723. They contained parallel blades and were called the Hands of Palfyn, which were possibly the instruments described by used in Paris by Gregoire father and son, Dussée and Jacques Mesnard.

In 1813, Peter Chamberlen’s midwifery tools were discovered at Woodham Mortimer Hall. In the attic of the house, the instruments were found along with gloves, old coins and trinkets. The tools discovered also contained a pair of forceps that were presumably invented by the father of Peter Chamberlen, assumed so because of the barbaric nature of the design.

The Chamberlen family's forceps were based on the idea of separating the two branches of sugar clamp, which were put in place one after another in the birth canal. This was not possible with conventional tweezers previously tested. However, they could only succeed in maternal pelvis of normal dimensions and on fetal heads already well engaged (i.e. well lowered into maternal pelvis). Abnormalities of pelvis were much more common in the past than today, which complicated the use of Chamberlen forceps. The absence of pelvic curvature of the branches (vertical curvature to accommodate the anatomical curvature of maternal sacrum) prohibited blades from reaching upper-part of the pelvis and exercising traction in the natural axis of pelvic excavation.

In 1747 French obstetrician Andre Levret, published "Observations sur les causes et accidents de plusieurs accouchements laborieux" (Observations on the Causes and Accidents of Several Hard Deliveries), in which he modified the instrument to follow the curvature of the maternal pelvis, allowing a grip on a fetal head still high in the pelvic excavation, which could assist in more difficult cases. This improvement was published in 1751 in England by William Smellie in the book " A Treatise on the theory and practice of midwifery." After this fundamental improvement, the forceps would become a common obstetrical instrument for more than two centuries.

The last improvement of the instrument was added in 1877 by a French obstetrician, Stephan Tarnier in "descriptions of two new forceps." This instrument featured a traction systemmisaligned with the instrument itself, sometimes called the "third curvature of the forceps". This particularly ingenious traction system, allowed the forceps to exercise traction on the head of the child following the axis of the maternal pelvic excavation, which had never been possible before. Tarnier's idea was to "split" mechanically the grabbing of the fetal head (between the forceps blades) on which the operator does not intervene after their correct positioning, from a mechanical accessory set on the forceps itself, the "tractor" on which the operator exercises traction needed to pull down the fetal head in the correct axis of the pelvic excavation. Tarnier forceps (and its multiple derivatives under other names) remained the most widely used system in the world until the development of the cesarean section.

Forceps had a profound influence on obstetrics as it allowed for the speedy delivery of the baby in cases of difficult or obstructed labor. Over the course of the 19th Century, many practitioners attempted to redesign the forceps, so much so that the Royal College of Obstetrics and Gynecologist collection has several hundred examples. In the last decades, however, with the ability to perform a cesarean section relatively safely, and the introduction of the ventouse or vacuum extractor, the use of forceps and training in the technique of its use has sharply declined.

Types of forceps

Eversince either peter 1 and peter 2  of the Chamberien family invented the forceps around A.D1600 , many designed were invented or modified. But only three varieties are commonly used in present day obstetric practice. These are

1. Long curvedforceps with or without axis traction device
2. Short curved forceps
3. Kielland’s  forceps

Design of forceps

Forceps vary considerably in size and shape, but basically consist of two crossing branches. Each branch has four components, 

The blade

The shank

Lock

Handle .

Each blade has two curves , the cephalic and pelvic. The cephalic curve conforms to the shape of the fetal head, and the pelvic curve with that of the birth canal.

The cephalic curve should be larger enough to grasp the fetal head firmly with out compression . the pelvic curve corresponds more or less to the axis of the birth canal but varies considerably among different instruments. The blades are connected to the handle by the shanks, which gives the requisites length to the instrument.

The kind of articulation or forceps lock varies among different instruments. The common method of articulation consist of a socket located on the shank at the junction with the handle , in to which fits a socket similarly located on the opposite shank. This forms of articulation is commonly referred to as the English lock. A sliding lock is used in some forceps , such as Kielland forceps and allow the shank to move forward and backward independently. In some cases, the operator chooses to use an axis traction device help to maintain the appropriate vector for a necessary delivery.

Indication for forceps delivery

1. Delay in second stage of labour  due to minor degree of cephalopelvic disproportion , persistent occipito posterior position , deep transverse arrest or secondary uterine inertia.
2. Foetal distress in the secondary stage of labour when the fetal head is engaged.
3. Prolapsed of the umbilical cord in the second stage of labour when the head is engaged.
4. In the delivery of the after coming head in the breech presentation
5. Maternal distress in the second stage of labour.
6. Prophylaxis in maternal conditions such as

a.       Cardiac disease

b.      Hypertension

c.       Preeclampsia and eclampsia

d.       Diabetes

e.       Chronic nephritis

f.       Pulmonary tuberculosis

g.      Prophylaxis in premature infants .

Choice of forceps operations /delivery

Mid forceps (10%)

It is used when head (station )is at or near the level of ischial spine. Internal rotation of the head is often incomplete. Manual rotation may be is needed before traction.

Low forceps (90%)

The head is near the pelvic floor or even visible at the introitus. It is commonly used now a days with advantages.

Outlet forceps

It is a variety of low forceps where the head is on the perineum. Thus , all outlet forceps are low forceps but not all the forceps are outlet forceps operations.

Types of application of blades

Cephalic application

The blades are applied along the sides of the head grasping the biparital diameter in between the widest part of the blades. The long axis of the blade corresponds more or less to the occipito – mental plane of the fetal head. It is the ideal method of application as it has got a negligible compression effect on the cranium

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 types of application puts serious compression effect on the cranium and thus must be avoided.

Functions of forceps

¨      Traction is the most important function of the forceps. In primigravidae , the pull required is estimated to about 18kg and that in multiparae about 13kg.

¨      Its compression effects on the cranium should be minimal when correctly applied over the biparital plaine and should not be more than required to grasp the fetal head.

¨      Rotation of the head can be achieved by  Kielland forceps. However in the low forceps operation with the sagital sutures placed obliquely , with the occiput placed say at 2 or 10 ‘o’ clock position . cephalic application of the blades of ordinary forceps and traction causes rotation of the sagital suture. So as to bring it in an antero- posterior diameter of he outlet.

¨      To provide a protective cage for the head from the pressure  of the birth canal as in premature baby or to control the delivery of the after coming head to lesson the dangers of sudden decompression.

¨      One forceps blade may be used as a vectis to assist delivery of the head in caesarian section.

Criteria to be fulfilled prior to forceps operation

1. Fetal and utero placental criteria

The fetal head must be engaged

The cervix must be fully dilated

The membranes must be ruptured

The position and station of the fetal head must be known with certainty .

2. Maternal criteria 

No major cephalo-pelvic disproportion by clinical pelvimetry

Bladder must be emptied

Adequate analgesia .

3. Others

Experienced operators

Verbal or written consent

                                           

Mnemonic for F-O-R-C-E-P-S

F :- Favorable head position and station

O :- Open os ( fully dilated )

R :- Ruptured membranes

C :- contraction present and consent

E :- Engaged head empty bladder

P :- pelvimetry no major CPD

S :- Stirrup,  lithotomy position

Classification of forceps delivery according to station and rotation

1. High forceps

Head is not engaged . this types is not included in classification

2. Mid forceps

Head is engaged in the pelvis but presenting part is above +2 station .

3. Low forceps

Leading point of the fetal skull is + 2 or more but has not get reached th pelvic floor (1) rotation is <45 ̊ (2) rotation is >45 ̊

4. Outlet forceps

¨      Scalp is visible at the introitus without separating the labia

¨      Fetal skull has reached the level of the pelvic floor

¨      Sagital sutures is in direct anterior posterior diameter

¨      Fetal head is at or on the perineum

¨      Rotation is <45 ̊

LOW FORCEPS DELIVERY

Low forceps delivery is the delivery of the fetal head which has descented below the level of the ischial spine . an episiotomy is done before the delivery is carried out

Preparation of the patient for forceps delivery

Indication

Maternal and foetal distress in the second stage of labour.

Types of forceps

Wrigley’s forceps is used for low forceps delivery .

Anesthesia

Pudentral block is supplemented by perineal and labial infilteration with 1% lignocain hydrochloride is quite effective in producing local anesthesia .

Catheterization

Internal examination to assess

1. state of the cervix
2.  membranous status
3. Presentation and position of the head
4. Assessment of the pelvic outlet

Episiotomy :- it may be done during traction when the perineum becomes bulged and thinned out by the advancing head.

Steps of forceps delivery

The operation consist of the following steps

®    Identification of the blades and their application

®    Locking of the blades

Step 1 identification and application of the blade

Step 2 locking of the blade

Step 3 and 4 traction and removal of the blades 

Step 1  identification and application of the blades

The identification of the blades is to be made after articulation as mentioned earlier. The left or lower blade is to be introduced first. The four fingers of the semi supinated right hand are inserted along the left lateral vaginal wall , the palmar surface of the fingers rest against the side of the head. The fingers are to guide during application and to protect the vaginal wall. The handle of the left blade during application and to protect the vaginal wall. The handle of the left blade is taken lightly by three fingers of the left hand . index , middle and thumb in a pen holding manner and is held vertically almost parallel to the right inguinal ligament

The fenestrated portion of the blade is placed on the right palm with the tip pointing upwards . the right thumb is placed at the junction of the blade and the shank .

The blade is introduced between the guiding inernal fingers and the fetal head manipulated by the thumb . as a blade is pushed up and up , the handle is carried downwards and backwards , traversing wide arc of a circle towards the left until the shank is to lie straight on the perineum. Utmost gentleness is required while introducing the blade . no assistant is usually required to hold the handle in low forceps operation . when correctly applied the blade should be in contact with the perineum and the superior surface of the handle should be directed upwards.

Introduction of the right blade

The two fingers of the left hand are now introduced in to the right lateral wall of the vagina along side the babies head. The right blade is introduced in the same manner as with left one but holding it with the right hand.

Step 2  locking of the blades

When correctly applied , the blade should be articulated with ease. Minor difficulty in locking can be corrected by depressing the handle on the perineum. In case of major difficulty the blades are to be removed , the cause are to be sought for (vide infra ) and  the blades are to be reinserted. The handle should never be forced to lock them

Step 3 and 4 traction and removal of blade

Before traction is applied , correct application of the blade to be ensured. Correct application is evidenced by

1. easy locking
2. the blades are equidistant from the lambdoid suture
3. firm gripping of the head on the bipolar diameter – as judged by a few tentative pulls.

Principles

Steady but intermittent traction should be given if possible during contraction. However in outlet forceps the pull may be continuous. Strong traction is not needed as the only resistance to overcome is the perineum and the coccyx .

Gripping of the articulated forceps during traction

The traction is given by gripping the handle, placing the middle finger in between the shanks with the ring and index fingers on either side on the finger guard. During the final stage of traction , the four fingers are placed in between the shanks and the thumb which is placed on the under surface of the handles exerts the necessary force.

Direction of the pull

The direction of the pull corresponds to the axis of the birth canal. In low forceps operation depending upon the station of the head , the direction of the pull is downwards and backwards until the head comes to the perineum. The pull is then directed horizontally straight towards the operator till the head is almost crowned. The direction of pull is gradually changed to upwards and forwards , towards the mothers abdomen to deliver the head by extension. The blades are removed one after the other , the right one first . 

Following the birth of the head , usual procedures are to be taken as in normal delivery. Routine intravenous methergin 0.2 mg is to be administered with the delivery of the anterior shoulder.  Episiotomy is repaired in the usual method . laceration on the vaginal walls or perineum are to be excluded .

OUTLET FORCEPS OPERATIONS

Wrigley’s forceps are used exclusively in outlet forceps operations . perineal and vulval infiltration with 1% lignocain is enough for local anesthesia . the blades are introduced as in the low forceps operations with long curved forceps except the two fingers are to be introduced into the vagina for the application of the left blade. Traction is given holding the articulated forceps with the fingers placed in between the shank and the thumb on the under surface of the handle. The direction of the pull is straight horizontal and then upward and forwards.

      MID FORCEPS OPERATIONS

The commonest indication of the midforceps operation is following manual rotation of the head in malrotated occipito –posterior position. The commonly used forceps is long curved one with or without axis traction device. Kiellands is useful in the  hands of an experts.

Procedures

General anesthesia is preferable

1. Introduction of the blades :- the introduction of the blades is to be done after prior correction of the malrotation .

a.       without axis traction device – the blades are introduced as in the low forceps operations. An assistant is required to hold the left handle after its introduction

b.      with axis traction device – while applying the left blade, the traction rod already attached to the blade is held backwards. During introduction of the right blade the traction –rod must be held forwards otherwise it will prevent locking of the blades.

2. Traction

a.       with out axis traction device – The direction of pull is first downwards and backwards then and finally upwards and forwards.

b.      With axis traction device – the traction handle is to be attached to the traction rods. During traction, the traction rod  should remain parallel with the shanks. When the base of the occiput comes under the symphysis pubis , the traction rods are to be removed.

Difficulties in forceps delivery

The difficulties are encountered mainly due to faulty assessment of the case before the operative delivery is undertaken. However there is hardly any difficulty in low forceps operation.

During application of the blades – The causes are

®    Incompletely dilated cervix

®    Unrotated or non-engaged head

Difficulties in locking – The causes are

®    Application in unrotated head

®    Improper insertion of the blade

®    Failure to depress the handle against the perineum

®    Entanglement of the cord or fetal parts inside the blades.

Difficulty  in traction –The causes of failure to deliver with traction are

1.      Undiagnosed occipito – posterior position

2.      Faulty cephalic application

3.      Wrong direction of traction

4.      Mild pelvic contraction

5.      Constriction ring

Slipping of the blades -  The causes are

• The blades are not introduces far enough
• Faulty application in occipito posterior position. The blades should be equidistant from the sinciput and occiput. 

Complication of forceps delivery

Maternal

Immediate

¨      Injury –

®    vaginal laceration or sulcus tear,

®    cervical tear ,

®    extention of episiotomy to involve the vaginal vault ,

®    complete perineal tear.

¨      Nerve injury :- femoral (L2, 3, 4 )

®    Lumbosacral trunk (L4, 5) with mid forceps delivery

¨      Postpartum hemorrhage may be

1. Traumatic
2. Atonic requiring blood transfusion  
3. Both may cause shock

Anesthetic complications

Purperial sepsis and maternal morbidity

Remote

®    Painful perineal scars

®    Dyspareunia

®    Lowback ache

®    Genital prolapse

®    Stress urinary incontinence

®    Sphincter  dysfunction

Fetal

Ø  Immediate

Ø  Asphyxia

Ø  Facial brusing

Ø  Intracranial hemorrhage

Ø  Cephal hematoma

Ø  Facial palsy

Ø  Skull fracture

Ø  Cervical spine injury  

Remote

Cerebral or spastic palsy due to residua cerebral injury

Nursing diagnosis

1. Alteration in comfort due to pain related to delivery process

®    Assess the types of pain ,types , duration and intensity

®    Provide comfortable  left lateral position to the mother

®    Provide psychological reassurance  to the mother

2. Potential for complication related to forceps application

®    Assess for any types of laceration

®    Maintain aseptic technique

®    Handle the case carefully

®    Case should handle by experts

®    Clean the perineal area with betadine

3. Potential for infection  related to forceps application

®    Assess for any scar

®    Maintain strict aseptic technique

®    Clean the surrounding

®    Avoid many visitors

4. Fear and anxiety of parents related to delivery process

®    Provide proper explanation about babies condition

®    Give information about progress of delivery frequently

®    Provide psychological reassurance to the mother 

®    Clarify the mother doubts