Forceps in childbirth
Encyclopedia
Forceps are a surgical instrument that resembles a pair of tongs and can be used in surgery for grabbing, maneuvering, or removing various things within or from the body. They can be used to assist the delivery
Childbirth
Childbirth is the culmination of a human pregnancy or gestation period with the birth of one or more newborn infants from a woman's uterus...

 of a baby as an alternative to the ventouse
Ventouse
Ventouse is a vacuum device used to assist the delivery of a baby when the second stage of labour has not progressed adequately. It is an alternative to a forceps delivery and caesarean section. It cannot be used when the baby is in the breech position or for premature births. This technique is...

 (vacuum extraction) method.

Structure

Obstetric forceps consist of two branches that are positioned around the fetal head. These branches are defined as left and right depending on which side of the mother's pelvis they will be applied. The branches usually, but not always, cross at a midpoint which is called the articulation. Most forceps have a locking mechanism at the articulation, but a few have a sliding mechanism instead, allowing the two branches to slide along each other. Forceps with a fixed lock mechanism are used for deliveries where little or no rotation is required, as when the fetal head is in line with the mother's pelvis. Forceps with a sliding lock mechanism are used for deliveries requiring more rotation.

The blade of each forceps branch is the curved portion that is used to grasp the fetal head. The forceps should surround the fetal head firmly, but not tightly. The blade characteristically has two curves, the cephalic and the pelvic curves. The cephalic curve is shaped to conform to the fetal head. The cephalic curve can be rounded or rather elongated depending on the shape of the fetal head. The pelvic curve is shaped to conform to the birth canal and helps direct the force of the traction under the pubic bone. Forceps used for rotation of the fetal head should have almost no pelvic curve.

The handles are connected to the blades by shanks of variable lengths. Forceps with longer shanks are used if rotation is being considered.

Anglo-American types

All American forceps are derived from French forceps (long forceps) or English forceps (short forceps).
Short forceps are applied on the fetal head already descended significantly in the maternal pelvis (i.e., proximal to the vagina). Long forceps are able to reach a fetal head still in the middle or even in the upper part of the maternal pelvis.
At present practice, it is uncommon to use forceps to access a fetal head in the upper pelvis. So, short forceps are preferred in UK and USA. Long forceps are still in use elsewhere.

Simpson forceps (1848) are the most commonly used among the types of forceps and has an elongated cephalic curve. These are used when there is substantial molding, that is, temporary elongartion of the fetal head as it moves through the birth canal.

Elliot forceps (1860) are similar to Simpson forceps but with an adjustable pin in the end of the handles which can be drawn out as a means of regulating the lateral pressure on the handles when the instrument is positioned for use. They are used most often with women who have had at least one previous vaginal delivery because the muscles and ligaments of the birth canal provide less resistance during second and subsequent deliveries. In these cases the fetal head may thus remain rounder.

Kielland forceps (1915, Norwegian) are distinguished by an extremely small pelvic curve and a sliding lock. Probably the most common forceps used for rotation. The sliding mechanism at the articulation can be helpful in asynclitic birth
Asynclitic birth
An asynclitic birth or asynclitism refers to the position of a baby in the uterus such that the head is tilted to the side, causing the fetal head to no longer be in line with the birth canal. Most asynclitism corrects spontaneously in the progress of normal labor...

s (when the fetal head is tilted to the side), since the fetal head is no longer in line with the birth canal. On the other hand, Kielland forceps lack traction because they have almost no pelvic curve.

Wrigley's forceps are used in low or outlet delivery (see explanations below), when the maximum diameter is about 2.5 cm above the vulva. Wrigley's forceps were designed for use by general practitioner obstetricians, having the safety feature of an inability to reach high into the pelvis.

Technique

The cervix must be fully dilated and retracted and the membranes ruptured. The urinary bladder should be empty, perhaps with the use of a catheter. High forceps are never indicated in this era. Mid forceps can occasionally be indicated but require operator skill and caution. The station of the head must be at least +2 in the lower birth canal. The woman is placed on her back, usually with the aid of stirrups or assistants to support her legs. A mild local or general anesthetic is administered (unless an epidural anesthesia has been given) for adequate pain control. Ascertaining the precise position of the fetal head is paramount, and though historically was accomplished by feeling the fetal skull suture lines and fontanelles, in the modern era, confirmation with ultrasound is essentially mandatory. At this point, the two blades of the forceps are individually inserted, the posterior blade first, then locked. The position on the baby's head is checked. The fetal head is then rotated to the occiput anterior position if it is not already in that position. An episiotomy
Episiotomy
An episiotomy , also known as perineotomy, is a surgically planned incision on the perineum and the posterior vaginal wall during second stage of labor. The incision, which can be midline or at an angle from the posterior end of the vulva, is performed under local anaesthetic , and is sutured...

 may be performed if necessary. The baby is then delivered with gentle (maximum 30 lbf
Pound-force
The pound force is a unit of force in some systems of measurement including English engineering units and British gravitational units.- Definitions :...

 or 130 Newton) traction in the axis of the pelvis.

Outlet, low, mid or high

The accepted clinical standard classification system for forceps deliveries according to station and rotation was developed by ACOG and consists of:
  • Outlet forceps delivery, where the forceps are applied when the fetal head has reached the perineal floor and its scalp is visible between contractions. This type of assisted delivery is performed only when the fetal head is in a straight forward or backward vertex position or in slight rotation (less than 45 degrees to the right or left) from one of these positions.
  • Low forceps delivery, when the baby's head is at +2 station or lower. There is no restriction on rotation for this type of delivery.
  • Midforceps delivery, when the baby's head is above +2 station. There must be head engagement before it can be carried out.
  • High forceps delivery is not performed in modern obstetrics practice. It would be a forceps-assisted vaginal delivery performed when the baby's head is not yet engaged.

Indications for use

Advantages to forceps use include avoidance of C-sect, reduction of delivery time, general applicability with cephalic presentation. Complications include the possibility of bruising, deformation, rectovaginal fistula
Rectovaginal fistula
A rectovaginal fistula is a medical condition where there is a fistula or abnormal connection between the rectum and the vagina. Rectovaginal fistula may be extremely debilitating. If the opening between the rectum and vagina is wide it will allow both flatulence and feces to escape through the...

, nerve damage, Descemet's membrane
Descemet's membrane
Descemet's membrane is the basement membrane that lies between the corneal proper substance, also called stroma, and the endothelial layer of the cornea. It is composed of a different kind of collagen than the stroma. The endothelial layer is located at the posterior of the cornea...

 rupture (extraordinarily rare), skull fractures, and cervical cord injury.
  • Maternal factors
  1. Maternal exhaustion
  2. Prolonged second stage
  3. Maternal illness; such as heart disease, hypertension, glaucoma, aneurysm, or other things which make pushing difficult or dangerous
  4. Haemorrhage
  5. Analgesic drug-related inhibition of maternal effort (especially with epidural/spinal anaesthesia)
    • Foetal Factors
  6. Non-reassuring foetal heart tracing

History

The obstetric 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 from Normandy origin but 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, who 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
Peter Chamberlen
Peter Chamberlen was the name of two brothers, the sons of William Chamberlen , a Huguenot surgeon who fled from Paris to England in 1576. They are famous for inventing the modern use of obstetrical forceps...

 (then Peter in England), who became obstetrician-surgeon of Queen Henriette
Henrietta Maria of France
Henrietta Maria of France ; was the Queen consort of England, Scotland and Ireland as the wife of King Charles I...

, wife of King Charles I of England and daughter of Henry IV, King of France.
He was succeeded by his nephew, Dr. Peter Chamberlen (also known as Doctor Peter, being the first to be graduated "Doctor", because barbers-surgeons were not Doctors), 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 this "secret" instrument allowing release of live child in difficult cases.

In fact, the instrument was kept secret for 150 years by the Chamberlen family, although there is evidence for its presence 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
François Mauriceau
François Mauriceau was a French obstetrician from Paris. He received his training in obstetrics at the Hôtel-Dieu.Mauriceau was a leading obstetrician in 17th century Europe...

, responsible for Paris Hotel-Dieu
Hôtel-Dieu de Paris
The Hôtel-Dieu de Paris is regarded as the oldest hospital in the city of Paris, France, and is the most central of the Assistance publique - hôpitaux de Paris hospitals. The hospital is linked to the Faculté de Médecine Paris-Descartes...

 maternity, was a resounding failure which resulted in the death of mother and child. 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 buyersn.

The forceps were used most notably in difficult childbirths. The forceps could avoid some infant deaths when previous approaches (involving hooks and other instruments) extract them in parts.. 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.

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.

These "hands" were possibly the instruments described and used in Paris by Gregoire father and son, Dussée, and Jacques Mesnard.

In 1813, Peter Chamberlen’s midwifery tools were discovered at Woodham Mortimer
Woodham Mortimer
Woodham Mortimer is a village on the Dengie peninsula about three miles west-south-west of Maldon in the English county of Essex. The village is part of the Wickham Bishops and Woodham ward of the Maldon district.-History:...

 Hall near Maldon
Maldon, Essex
Maldon is a town on the Blackwater estuary in Essex, England. It is the seat of the Maldon district and starting point of the Chelmer and Blackwater Navigation.Maldon is twinned with the Dutch town of Cuijk...

 (UK). 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" (as those used to remove "stones" from bladder), 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
André Levret
André Levret was a French obstetrician who practised medicine in Paris. He was a contemporary of famed English obstetrician William Smellie , and along with Jean-Louis Baudelocque helped advance the science of obstetrics in 18th century France.Levret is considered by many the most influential...

, published "Observations sur les causes et accidents de plusieurs accouchements laborieux" (Observations on the Causes and Accidents of Several difficult Deliveries), in which he described his modification of the instrument to follow the curvature of the maternal pelvis, this "pelvic curve" 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
William Smellie (obstetrician)
William Smellie was a Scottish obstetrician.He practiced medicine before getting a licence, but enrolled later at the University of Glasgow and received his M.D. degree in 1745. After training in obstetrics in London and Paris, he opened a practice in London and began teaching...

 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 system misaligned 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
Childbirth
Childbirth is the culmination of a human pregnancy or gestation period with the birth of one or more newborn infants from a woman's uterus...

. Over the course of the 19th Century, many practitioners attempted to redesign the forceps, so much so that the Royal College of Obstetrics and Gynecologists' 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
Ventouse
Ventouse is a vacuum device used to assist the delivery of a baby when the second stage of labour has not progressed adequately. It is an alternative to a forceps delivery and caesarean section. It cannot be used when the baby is in the breech position or for premature births. This technique is...

or vacuum extractor, the use of forceps and training in the technique of its use has sharply declined.
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