Breech Presentation.—The pelvic pole enters the inlet first, once in thirty cases and more commonly in primiparas than otherwise.

Etiology.—Anything that interferes with or deranges the laws of normal gestation will predispose to, or produce this anomaly.

Thus, if the head is too large, as in hydrocephalous, or if the foetus is too movable, as in hydramnios, or if an obstacle, like placenta previa, contracted pelvis or tumors prevent the proper approach of the head to the inlet, the mechanism will be disturbed and a breech or possibly a shoulder presentation will result.

Abnormal flaccidity of the uterine or abdominal walls, prematurity or twins also contribute definitely to its occurrence.

The attitude of the child generally retains its normal aspect of complete flexion. This pose, however, is not maintained invariably for on occasion the buttocks and genitals may rest upon the inlet while one or both feet may be extended on the thighs and lie beside the neck, or the thighs may be extended while the knees remain flexed, and what is known as a knee presentation, or if the foot comes down, a footling presentation results.

Positions.—The sacrum is the most prominent bony landmark of the breech, hence the positions are named from the relation this bone bears to the four quadrants of the inlet.

We have therefore in their order of frequency the following designations: Left-sacro-anterior, where the sacrum lies to the left of the median line of the mother’s body and in front; right-sacro-anterior, where the sacrum lies to the right and in front; right-sacro-posterior, where the bone lies near the mother’s vertebral column, and on the right side; and the left-sacro-posterior position, where the bone occupies a corresponding place on the left side.

Diagnosis.—The recognition of this presentation is most easily secured by external abdominal palpation in pregnancy, which may be reinforced during labor by the internal examination.

Externally the palpating fingers at the pelvic brim will note the absence of the hard, round head, and feel a mass, softer, quite irregular in shape, and less defined than customary. Movements also may be appreciated that would be too far down in the uterus if the head was presenting.

Next the hard, spherical tumor of the head can be outlined somewhere in the fundus, and the heart tones, instead of being below the umbilicus will be on the same level or even higher.

Vaginally the cervix is not filled out, the presenting part does not come down, but after labor has begun the distinctive features of the breech gradually become more evident, as they are driven into the pelvis.

One or both feet, or the buttocks, may be recognized. The examining finger may possibly enter the anus and be stained with meconium or pinched by the sphincter, which differentiates this orifice from the mouth.

One after another the characteristic landmarks appear until the diagnosis can not be doubtful. As soon as the sacrum is found or the legs definitely placed, the position can be named.

Mechanism.—The hips always enter the inlet in one of the oblique diameters and the back is turned to the same part of the uterine wall as in the corresponding vertex positions.

The acts described in the mechanism for vertex deliveries show a somewhat different order. Descent is first, then comes internal anterior rotation, which brings the anterior hip under the symphysis and its delivery is quickly followed by the posterior hip, which rolls out over the perineum.

The body advances, as a rule, with the back toward the front of the mother. The shoulders with arms folded move under the pubic arch and then the head delivers in a state of flexion. The head, of course, has no caput and it is not moulded.

This mechanism may be greatly impeded or complicated at any stage of the movement. The advance may be retarded to a pathological degree, the belly may be large and as it passes along the canal one or both arms may be stripped up alongside the head or even into the back of the neck. The head may be arrested at the inlet by the arms, by its degree of deflexion, or by pelvic contraction.

The rotation may not take place, or it may be abnormal, and the belly of the child look forward toward the mother’s. Any of these variations adds further to the difficulty of the labor and to the danger of the partners in the event.

Artificial aid may be required which brings with it the possibility of sepsis.

The foetal mortality which averages five per cent is due mostly to asphyxiation. Interference with the supply of oxygen begins as soon as the cord passes the vulva and the child must be delivered in eight minutes from that time, or perish. Partial detachment of the placenta may also cut off the oxygen to a fatal degree, and the child may be unable to breathe when born on account of mucus sucked into the trachea by premature efforts at respiration.

Minor accidents also occur, such as fractures, dislocations, and paralysis from injury to the nerve trunks.

Management.—In the interest of the child, this presentation is occasionally converted into a vertex by external version during the last weeks of pregnancy or in labor before the membranes have ruptured. It is difficult, however, to maintain the vertex over the inlet. The woman must be kept quiet in a horizontal posture and long roller splints applied to the side of the child in utero and bound on.

In primiparas, this is nearly impossible, and it is wiser, in the absence of some great necessity to warn the parents of the conditions and dangers and let them share in the responsibility.

When the labor begins, the bag of waters must be kept from rupture as long as possible and when it finally breaks, an internal examination should be made to see if the cord has come down. If this happens it may be necessary to expedite the delivery by external assistance.

The doctor brings down a foot, if it is not already down, or pulls on the breech until the feet drop out. Compression of the cord must be always in mind. It is always compressed after the umbilicus has passed the navel. The shoulders are delivered by seizing the feet with the operating hand and swinging the body out of the way. This brings the posterior shoulder, which should be first, into the hollow of the pelvis. Extraction is then completed by what is called the Smellie-Veit maneuver. The child is put astride one arm, the first finger of which is hooked into the child’s mouth to maintain flexion. The fingers of the other hand then grasp the shoulders of the child astride the back of the neck and traction is made downward in the axis of the inlet until the head slips into the excavation.

If the head is delayed at the inlet, it may be necessary to put the woman in the Walcher position (q. v.) and for the nurse to use the Wiegand compression (q. v.). The feet must not be fastened in stirrups for breech cases.

Forceps are not recommended for application to the breech as they do not fit and are liable to slip off and injure both child and mother. The fingers are best.

Forceps are not recommended for the after-coming head unless the child is dead. If the child lives, the Smellie-Veit is more-successful; and if the child dies, the cranioclast, if possible, will save the mother much suffering and avoid some injury to the tissues.

Transverse or Shoulder Presentations.—These are cases in which the long axis of the child lies directly across or obliquely across the long axis of the uterus.

The shoulder (scapula) is the bony landmark, and the part which most frequently impends over the inlet. This presentation probably occurs once in two hundred labors.

It is due to the same conditions that were given for breech cases; namely, weak abdominal or uterine muscles, pelvic contraction, placenta previa, hydramnios, and twins.

It is easily recognized in pregnancy, and must not be neglected, for it is impossible of delivery without first changing it into a longitudinal presentation. If this correction is not done, rupture of the uterus is liable to occur, with the consequent death of both mother and child.

The treatment is invariably version.

Face and Brow Presentations.—The face presents once in about three hundred labors. In this case, the head is completely extended so that the occiput rests against the back of the neck. The trunk and spine are straightened out while the legs and arms remain in the normal attitude of flexion.

The causes of these anomalies must be sought in those conditions which bring about the deflexion of the chin. The most common are pelvic contraction, large child, placenta previa, hydramnios, goiter, anencephalus and multiparity.

Face positions take their names from the location of the chin (mentum—Latin). Thus the most frequent face position is the right-mento-posterior.

The diagnosis is not easy and may not be conclusive until the bony prominences of the face, such as the nose and orbital ridges can be distinguished by vaginal examination.

The delivery is protracted from three to five hours beyond the average by this complication, and the mortality is higher both for mother and child. The face is badly swollen and disfigured, but the normal condition of the tissues will be restored by the end of a week. Most face cases terminate spontaneously, but operative interference is not infrequent on account of danger to mother or child.

Version or manual correction of the presentation may be done before engagement.

Forceps is the operation of choice after the head is fixed in the pelvis, but it may be necessary to precede the delivery by a preparatory pubiotomy, or in case of failure, to do a craniotomy on the dead child.

If the chin does not rotate forward under the symphysis, the labor is impossible without pubiotomy or the destruction of the child. In general, the case should be left to nature unless some definite indication to interfere develops.

The brow presents much more rarely than the face, possibly once in a thousand labors. It is due to the same conditions as bring about the presentation of the face. The mortality for both mother and child is higher than in face cases. The whole labor is harder and longer, besides being more dangerous to life and to tissues.

This presentation, if recognized before the head is fixed, should be converted into a breech by version, but after the head comes down, it may be possible by hand or forceps to deliver either as a face or as an occipito-posterior, but otherwise the cranioclast must be considered.

Occipito-posterior position is the name given to vertex cases wherein the occiput lies in one or the other of the two posterior quadrants of the pelvic inlet.

These labors are necessarily prolonged, both in the first and second stages, because the mechanism of delivery is deranged by the larger diameters brought into relation with the bony canal and by the ineffectiveness of the contractions.

The pains in the second stage may become violent and extremely painful, but the labor does not advance appreciably. After a little experience, mere observation of the course of the labor will cause the suspicion to arise in the mind of a competent nurse that the occiput is posterior. The diagnosis will be cleared up by the doctor’s internal examination, which shows the large fontanelle anterior and the sagittal suture running backward.

The head is partially deflexed and it may not be possible at first to find the small fontanelle.

The position terminates by delivery uncorrected, by spontaneous rotation into an anterior position, or is corrected by the doctor.

Correction should not be attempted until it is apparent that the anomaly will not right itself, which it will do in four cases out of five.