FORCEPS DELIVERY

The majority of obstetrical operations are done by means of a special instrument, the forceps. This consists of two separate thin steel blades with smooth inner surfaces curved to fit the sides of the infant’s head. The blades are inserted separately into the vagina, opposite each other, and when their handles are articulated, the child’s head is securely grasped between the blades. With moderate traction on the handles, exerted in the axis of the vagina, the head is extracted.

The word forceps in Latin means ‘a pair of tongs.’ It is said to have been derived from the earlier Latin words for-mus (‘hot’) + capere (‘to take’). The obstetric forceps in its modern form, an instrument capable of extracting a living child without injury to it or the mother, is an invention of the early seventeenth century. Previous to this, single-bladed and even double-bladed instruments, called hooks, were in use, but probably only for the extraction of a dead child. The old double-bladed instruments had a permanent articulation so that each blade could not be inserted separately; they looked like the once-familiar ice tongs.

The inventors of the modern obstetrical forceps were a singular medical family—the Chamberlens. In 1569 the first of the English line, William, emigrated from France to London to escape Huguenot persecution. Most of the Chamberlens were Royal Surgeons or Physicians, and several English queens were delivered by them. This obstetrical dynasty of Chamberlen extended uninterruptedly from Peter the Elder’s admission to the Guild of Barber-Surgeons in about 1596 to the death of Hugh, Junior, in 1728. They were no ordinary men; they lived hard and tempestuously, unwilling to confine their energies within the narrow scope of their profession.

History of the Forceps

The forceps were probably invented in about 1600 by Peter the Elder and kept as a hereditary family secret to be buried with Hugh, Junior, in 1728. According to modern medical standards, such conduct was wholly unethical, and any twentieth-century doctor who would dare a similar practice would find himself ostracized, read out of all medical societies, and anathema to decent people. However, it is obviously unfair to judge the behavior of one century by the standards of another.

How was the secret finally revealed? The existence of the forceps was hinted at as early as 1616 at a meeting of the Royal College when a slurring reference was made to the boast of Peter Chamberlen the Younger ‘that he and his brother, and none others, excelled in the management of difficult labors.’

Hugh, Senior, emigrated to Holland in 1699 under suspicion of debt. While there he appears to have obtained some money, for he returned to England for two years before settling permanently in Amsterdam. While in Holland, probably at the time of his supposed flight, he sold the secret of the forceps to Hendrik Van Roonhuyze, the leader of Dutch obstetrics. During the succeeding years of the early eighteenth century the secret oozed out in England and on the Continent. William Giffard of London used the forceps openly on April 6, 1726, calling them extractors. He is generally considered ‘the altruistic and honorable physician who should receive full credit for introducing the forceps into general use in England.’ By 1733, when Edmund Chapman published the very first account of the forceps, there were already several models, and their use ‘was well known to all the principal men of the profession, both in town and country.’

The retention of an important medical secret transmitted from generation to generation for a century and a quarter is unique in history. The Chamberlens were crafty enough to exclude all others from the room when they operated; they used the forceps unassisted.

Not because of its antiquity—for other obstetrical operative procedures antedated it—but because of its importance, delivery by forceps merits first place in the discussion of obstetrical operations.

Conditions Necessary before Forceps Can Be Used

A delivery by forceps can be done only under definite conditions: if the child presents head first, the head fits the pelvis without any disproportion, the membranes are ruptured, and the cervix is completely dilated. This means it cannot be done before the second stage of labor, except in the very rare case when the obstetrician stretches or cuts the last remaining undilated portion of the cervix to effect immediate delivery.

Indications for a Forceps Delivery

Indications for delivery by forceps are obviously divided into two broad classes—fetal and maternal. The sole fetal indication is acute distress of the unborn child, evidence of which is displayed by an irregular fetal heart with a rate below 100, particularly when coupled with the appearance of brown or dark green amniotic fluid in a head presentation. This change in the ordinarily colorless fluid is caused by contamination with fetal intestinal contents (meconium). If the fetus is in poor condition, the anal sphincter (rectal muscle) relaxes and allows meconium to be expelled. (The appearance of meconium in a breech presentation is normal and of no significance.) In the main there are two causes which account for these signs of fetal distress: a disturbance in the placental-fetal circulation, leading to deprivation of oxygen for the child; or pressure on the head of the child from the stress of labor. Any of a number of accidents may cause interference with the fetus’s oxygen supply: the cord may prolapse (slip down) into the vagina, the abnormal situation permitting its compression between the child’s body and the rigid walls of the pelvis; or the umbilical cord may become shortened from looping itself about the child’s neck so that, as the child descends, the cord is made so taut that its blood vessels are constricted. Premature separation of the placenta may also interfere with the fetal-placental circulation by lifting up and putting out of function large areas of the placental bed. The second source of fetal distress, excessive pressure on the head, may result from a short, stormy labor or a very long one—either may cause cerebral concussion or hemorrhage. When there is an acute slowing of the fetal pulse, particularly when associated with meconium-stained amniotic fluid, delivery is wise. If the head is sufficiently low in the pelvis and the cervix completely dilated, a prompt forceps delivery offers the best solution.

The maternal indications for forceps are many. The mother may be ill with heart disease, tuberculosis, a toxemia of pregnancy, or some other serious illness; if so, it is wise to shorten labor. Or perhaps the patient has been delivered in a previous pregnancy by Cesarean section and to protect the uterine scar from rupture one spares it some of the severe strain of the second stage of labor by a forceps delivery as early as feasible. Then, too, mother and fetus may both be in excellent condition but a forceps may be indicated by lack of progress in labor. If the cervix is fully dilated, the head very low in the pelvis, and there is no progress for an hour, it is best to interfere for the sake of both mother and child. If the head is higher, usually a two-hour or longer period without progress after full dilatation of the cervix is permitted before a forceps is undertaken.

The indications I have described are agreed upon by all obstetricians, but this is not true of the so-called ‘prophylactic forceps,’ which may be done as a matter of routine as soon as the head impinges against the perineum, particularly in first births. Proponents of the prophylactic forceps, who include most obstetricians of this country, as well as the author, claim that it spares the fetal head from prolonged pressure against a rigid perineum, and that the mother is relieved of much of the strain of the terminal part of labor. Also, if one combines the prophylactic forceps with an episi-otomy (anticipating a tear by cutting the perineum), the maternal tissues are left in better condition at the conclusion of the delivery than if a spontaneous birth were allowed. Those opposed damn it with the catch phrase, ‘Meddlesome midwifery.’

The Performance of a Forceps Delivery

Before a forceps operation the patient is fully anesthetized, positioned on the table, cleansed, draped, and usually catheterized. The operator performs a careful vaginal examination to determine the position of the head. This is done with the aid of familiar landmarks, the two soft spots (fontanelles) at the front and back of the child’s head. The one in front is relatively large and diamond-shaped, while the one in back is small and triangular. The operator can corroborate his fontanelle findings by crowding bis fingers alongside the head and sliding them above it to feel the baby’s ear, since the front of the ear is fixed, while the back is loose and floppy.

After accurately diagnosing the exact position in which the baby’s head lies, he picks up one blade of the forceps and inserts his other hand in the vagina. He then gently slides the blade along the palm of his vaginal hand so that it is insinuated between the vaginal wall and the fetal head. He then shifts the blade so that the child’s ear underlies the center of the blade. Now properly placed, the first blade is held firmly in position while the operator introduces the second blade, manipulating it so that it comes to rest on a straight line opposite its fellow. For example, if one imagines the pelvis as a clock with twelve in front at the top, and one blade is inserted at three o’clock, the other would be inserted at nine; or if the first blade is inserted at half-past five, the other would be placed at half-past eleven. The two handles are then locked. If the forceps are properly applied, the handles lock easily; if not, they must both be removed and reinserted. An experienced forceps operator knows that forceps injuries to the baby are the result of an imperfect application of the blades, and he will spend limitless time and patience in getting just the application he desires. When he is satisfied that both blades are well applied to the sides of the head he begins his forceps extraction.

The head cannot be born unless a line drawn down the center of its long axis is parallel to the longitudinal axis of the pelvic outlet. Obstetrical forceps have two functions—to rotate and to extract. The operator first rotates the head so that these two axes are parallel, the blades at three and nine on our imaginary dial. He does this by turning the handles through the necessary arc. This accomplished, he begins the extraction, pulling steadily for fifteen or twenty seconds, then releasing traction momentarily before he pulls again. The cycle is repeated over and over. The head descends little by little with each tug; when it distends the perineum, an episiotomy is performed. Soon the head is almost completely born, the forceps blades slipped off, and delivery of the head completed by a lifting motion on the chin applied through the mother’s tissues, the perineum. The delivery of the rest of the child is the same as in a spontaneous birth.

The amount of force necessary to perform a forceps operation depends on the point in the pelvis to which the head has already descended and on the size of the baby and the pelvis. An easy delivery requires relatively little force, but a difficult one requires brawn. Forceps operations are divided into high, mid, low, and outlet, depending on the point in the pelvis the head has reached when the operation is begun. The guide points which differentiate the various types are the same ischial spines I mentioned in describing a spontaneous birth. If the head has descended to the level of these spines, it is a mid-forceps; it is a high forceps when the head is above the spines, and a low forceps when the head is below them. When the scalp of the child is visible before the operation is begun, it is termed a perineal or outlet forceps.

The high forceps has fallen into complete disuse because of the great damage which it so often causes to the maternal tissues and the child. Cesarean section, which is far safer for both patients, has been substituted.

The incidence of forceps operations varies markedly in different clinics, depending on the parity (number of previous deliveries), race, and social status of their clientele. It is much higher among private patients. It also depends on whether or not the clinic practices routine prophylactic forceps.

There are as many models of forceps as there are kinds of baseball bats. In some instances a new forceps merely represents a slight modification of some pre-existing standard instrument—perhaps an inch longer or an inch shorter. In my opinion it makes relatively little difference which forceps is used as long as the operator is skilled in the use of that particular instrument to accomplish delivery under the circumstances presented by the case at hand. Obstetricians may sing paeans of praise for the Smith or the Jones instrument, but it is largely a matter of the instrument to which one is accustomed by training and use.