How Wide Is a Babys Shoulders When Born?

Definition and incidence

Shoulder dystocia is fundamentally a mechanical problem. The average gynecoid pelvis at the inlet is 12 cm in the anteroposterior diameter and xiii cm in the transverse diameter. The average sized fetus has a biacromial diameter of about 12–fifteen cm.^1,2 The shoulders are commonly in the anteroposterior diameter higher up the pelvic inlet merely they traverse the pelvic inlet in the larger transverse bore.ⁱⁱⁱ Although the biacromial diameter is oft larger than the transverse diameter of the pelvic inlet, there is usually no obstruction because the shoulders are compressible and they are pushed forward toward the fetal chest. It can be a tight fit.⁴

By the time the head has exited the vulva, the fetal shoulders have usually traversed the pelvic inlet. Nigh 20% of the fourth dimension the shoulders are nevertheless in the anteroposterior bore or slightly obliquely and volition not traverse the inlet until the next uterine contraction, ancillary with maternal pushing.³ If one believes that the shoulders must follow immediately after the head and thereby starts exerting downward traction on the caput, 1 may interfere with the rotation of the shoulders at the inlet and contribute to an iatrogenic shoulder dystocia. At other times, there is a 18-carat mechanical impediment to delivery. If the chest circumference is also big and the biacromial bore is, say, sixteen or 17 cm the shoulders may not exist able to enter even a normal sized pelvis. Most cases of shoulder dystocia are, indeed, acquired by a big fetus trying to get through a normal sized pelvis. A few instances occur when an average sized fetus is trying to get through a small pelvic inlet. One can appreciate how a 3,700 grand fetus with a biacromial bore of 15 cm may take trouble getting the shoulders through a pelvic inlet of 11 × 12 cm.

Shoulder dystocia is a subjective diagnosis. The only objective definition that has been proposed is a head-to-torso commitment interval of more than 60 seconds.⁵ By this definition, some ten% of vaginal cephalic deliveries would be considered as having shoulder dystocia. This definition makes little sense, especially for those deliverers who adopt to wait for the adjacent contraction subsequently delivery of the head to get the shoulders delivered. The American⁶ and British⁷ Colleges of Obstetrics and Gynecology ascertain shoulder dystocia as the failure of the shoulders to deliver with maternal pushing and gentle downwardly traction on the caput. One problem with this definition is that you lot often have the mother pushing in the absence of a wrinkle and the second is that it implies that pulling on the head is allowed and is a normal feature of delivery. I will address this when discussing the topic of brachial plexus injury without shoulder dystocia. The definition that I prefer, merely it is in the minority, is the failure of the mother to deliver the shoulders with her own maternal try during the next contraction afterward the contraction that has delivered the head.

The reported incidence of shoulder dystocia is very variable, only seems to take increased in the terminal several decades. Whereas in the mid-20th century the usual reported incidence was 0.5% or less, information technology is now usually reported in the ii%–three% range, equally loftier every bit 5% range,^eight and even >10% if 1 uses the head-to-trunk delivery interval. Part of this increased incidence is certainly due to the fact that at that place are more big babies beingness born than in the past. One speculation is that the increased utilise of epidural anesthesia and the practice of having women deliver on their backs might exist responsible.⁹ It is certainly plausible that a adult female unencumbered by epidural anesthesia and allowed to presume her own position for pushing would probably be able to push button the shoulders out more than easily. In any event, in round figures, the likelihood of encountering shoulder dystocia after a vaginal cephalic delivery is about one% for babies weighing under iv kg, about 5% for babies weighing between 4 and 4.v kg, and about x% for babies weighing more than four.5 kg.

Consequences of shoulder dystocia

Shoulder dystocia is a serious emergency for the baby. Once the head has delivered and one has the usual blazon of shoulder dystocia where the posterior shoulder is below the sacral promontory, the baby's breast is compressed. Although the nose and oral cavity are free, the infant cannot breathe because the breast is compressed. The uterus may still be contracting and interfering with blood supply to the placenta. If at that place is some umbilical cord compression, hypoxemia and acidosis may beginning to develop. If there is fractional umbilical cord compression, the fetal heart may proceed to pump blood through the less compressible umbilical arteries into the placenta, but pinch of the more hands compressed umbilical vein may not allow claret to render from the placenta back to the fetus. Forth the same lines, the increased intrathoracic pressure may not allow filling of the fetal eye. Barnum¹⁰ hypothesized this every bit a cause of infant decease due to shoulder dystocia and the hypothesis has been proposed¹¹ that hypovolemic stupor may be the reason why some babies are unresuscitatable after shoulder dystocia. It has also been speculated that compression of the fetal cervix may interfere with blood flow to and blood drainage from the brain, simply this would not business relationship for the failure of resuscitation in some cases. As a dominion of pollex, once one gets to the 5-minute mark or and then with unresolved shoulder dystocia at that place is a real adventure of expiry or encephalon damage to the baby and one may accept to think of extraordinary measures to resolve the shoulder dystocia. There are also implications for how to bear the resuscitation of the infant, which will be discussed later.

Whereas death and brain damage are a event of the shoulder dystocia itself, the other less grave but still serious complexity of brachial plexus injury is near e'er a outcome of the accoucheur trying to resolve the shoulder dystocia. I am skeptical that permanent brachial plexus injury can occur without some imposed traction. I acknowledge that when the head is delivered and i or both shoulders are trapped at the pelvic brim that the cervix and brachial plexus nerves may exist under more stretch than usual. But the idea that the shoulders are caught up by the bony pelvis and that the uterine contractions and maternal pushing efforts go on to push the head forwards while the shoulders are trapped or, in other words, the head keeps moving while the shoulders are stuck – the head is pulling the body – is too fanciful for me. It was clearly shown more than a century ago with cadaver experiments that traction on the baby's head in a direction away from the trapped shoulder makes the brachial plexus nerves taut like violin strings and that it does not have much force to have them snap.^12,thirteen It is true that just considering traction is the main cause of permanent brachial plexus injury information technology does not mean that all brachial plexus injuries are caused by traction, simply the vast majority are.

There are three lines of evidence that are proposed as supporting the idea that brachial plexus injury may exist a non-traction injury. The first is the occurrence of brachial plexus injury without described shoulder dystocia. I present one of the complications in my early career that might explain this phenomenon.

The mother had type 1 diabetes. The caput delivered easily. In anticipation of possible shoulder dystocia, the legs had been brought into McRoberts' position. After the head was delivered, I put my hands on the sides of the head and asked the mother to push and I pulled down while the patient pushed. The shoulders delivered hands. The baby weighed just over 4 kg. Equally far as I was concerned, there had not been any shoulder dystocia because there had been no difficulty delivering the shoulders. When I went to make rounds the adjacent morning, I found to my chagrin that the baby had a brachial plexus injury in the arm that had been anterior. The injury took over a year to heal with most, but non quite, complete render of function.

When there is a brachial plexus injury and no shoulder dystocia is recorded, it is possible that sometimes this is a deliberate omission of documentation by the obstetrician and so to have the defense that this was a non-iatrogenic injury. But, more often, it is likely a case where the usual customary method of delivery of the shoulders succeeds and shoulder dystocia is not appreciated. If, for example, 1 requires (every bit the standard definitions do) that the diagnosis of shoulder dystocia exist made only after gentle downward traction has failed to deliver the inductive shoulder, and then, if with perceived gentle downward traction the anterior shoulder is delivered, then the diagnosis of shoulder will not exist made, simply the brachial plexus could be injured. This is what I suspect happened in my case.

A second line of show proposed in back up of the non-traction theory of brachial plexus palsy is that the obstetrician genuinely did not put any more traction to evangelize the head than what he had always washed. I present another serious brachial plexus injury in my career.

This injury occurred in the babe of a type two diabetic adult female. In the 2nd phase, the maternal heart rate was existence recorded instead of the fetal heart charge per unit. When this was discovered and the fetal eye rate was checked it was severely bradycardic and a midcavity vacuum delivery was washed. Shoulder dystocia was identified, which was resolved by commitment of the posterior arm, which led to a fracture of the humerus. The infant was born in a depressed condition with metabolic acidosis and had moderate encephalopathy. The babe recovered well from the encephalopathy but at 1 month of age I discovered that the baby had a brachial plexus injury of the upper arm. When in that location was trivial improvement by 1 year of age, reconstructive surgery was done simply at iii years of age there was notwithstanding meaning handicap. I cannot remember, and the notes do not betoken, if downward traction was made on the head before the shoulder dystocia was resolved by delivery of the posterior arm (or, possibly, afterwards the posterior arm was delivered to deliver the anterior arm), but presumably at that place was. Certainly there was no downwardly traction out of the ordinary by the resident or myself equally I would have remembered that.

Almost obstetricians take been taught that after commitment of the head they should put their hands on either side of the head, ask the mother to push button, and then pull gently down on the head. If shoulder dystocia is encountered they are taught to try McRoberts' position or suprapubic pressure and pull gently down once more. The not bad bulk of the time both shoulders are already through the inlet by the time the head is delivered. Since the shoulders are not stuck when the obstetrician puts his hands on the side of the head and pulls on the head, there is no impediment to the shoulders and caput moving together, and then no harm is done. The obstetrician gets used to pulling with a certain amount of traction and the dandy majority of the time no harm is washed.⁹ But for the very infrequent case where one or both shoulders are still at the pelvic brim and the shoulders do not easily follow the caput, and then a customary level of traction that caused no problem in hundreds of cases beforehand may be plenty (especially if the fetus is asphyxiated and has no musculus tone) to cause serious injury to the brachial plexus.

The third argument proposed in support of the non-traction etiology for brachial plexus injury is the occurrence of brachial plexus injury in the arm that was posterior. If the anterior shoulder is trapped backside the pubic symphysis and the posterior shoulder is in the sacral hollow and, instead of delivering the posterior arm and shoulder directly, one pulls on the head in an upward direction, the neck and contained posterior brachial plexus can exist overstretched. This was clearly shown in a picture show in an 1897 article.¹² Some other way to damage the posterior brachial plexus is to rotate the nonrestituted head the incorrect mode and and then pull.^xiv

I do not retrieve that the trouble of brachial plexus injury volition be solved unless obstetricians acknowledge that traction is almost invariably the crusade instead of proposing other theories to spare us medicolegal problems.

Prevention of shoulder dystocia

Well-nigh half of shoulder dystocia cases occur in the 10% or then of women delivering a baby weighing iv kg or more. It stands to reason that if there were fewer big babies born at that place would be less shoulder dystocia. The main determinant of a babe's nativity weight in nondiabetic women is the weight of the female parent before pregnancy and the corporeality of weight she gains during pregnancy. In a perfect world, overweight women would become to their ideal weight before conception but losing weight is hard and not probable to be widely accomplished. With respect to weight proceeds during pregnancy, it was common practice decades ago for the obstetrician to chide the pregnant woman if she were gaining as well much, merely obstetricians nowadays are loath to be scolding their patients.

The other clear risk factor for delivering a infant more than four kg is maternal diabetes. Women with diabetes have about a 20% gamble of delivering a baby more than than 4 kg. The principal reason to treat diabetic women with oral hypoglycemics and/or insulin is to reduce the chance of third trimester stillbirth but, of course, handling will as well reduce the chance of macrosomia. Once a woman with diabetes has a fetus with impending macrosomia (abdominal circumference measurement of about 360 or so), delivery should be strongly considered, not and so much to reduce the run a risk of shoulder dystocia just rather to reduce the chance of unexplained stillbirth. Some women during pregnancy do not have a degree of hyperglycemia that poses any meaning risk of stillbirth, but, nevertheless, glucose-lowering treatment volition reduce the hazard of macrosomia and presumably shoulder dystocia.¹⁵ Whether it is desirable to treat a few dozen women with insulin to forbid one shoulder dystocia is unsettled.

With respect to prevention of shoulder dystocia, withal, about 90% of cases occur in women who are not diabetic. About 50% of cases will occur in women whose baby weighs more than than four kg. Ultrasound interpretation of fetal weight is imprecise, but likely improve than clinical interpretation lone. An abdominal circumference of under 360 nearly never indicates a fetus over 4,500 g. An abdominal circumference of 400 mm has a very high likelihood that the nascence weight will be over 4,500 g. Between 360 and 400, there is a lot of inaccuracy. A frequently proposed remedy to reduce the hazard of shoulder dystocia and its serious complications is to perform an elective cesarean section if the estimated fetal weight is four,500 g or more. In Tabular array i, I have estimated what such an approach would hateful for the population of the infirmary that I work at.

Table i Estimated number of permanent BPI prevented by routine CS for fetuses greater than iv,500 grams Notes: Policy of routine CS if >4,500 chiliad results in two,000+2,600=4,600 CS. Of these, 600+(xv% of 2,600)=i,000 would have had a CS in labor. Therefore: 3,600 extra CS. Would have prevented 3 BPI in >4,500 k and iii BPI in the 2,600 women in iv,000–4,500 grand group who avoided attempted vaginal commitment. Abbreviations: BPI, brachial plexus injury; BW, nativity weight; CS, caesarean section; Perm, permanent; SD, shoulder dystocia.

One can see that one would have to perform some 600 extra cesarean sections to forbid one example of permanent brachial plexus injury. Of course shoulder dystocia can lead to fetal brain damage so it is possible that the 600 extra cesarean sections would likewise forestall the rare case of baby brain damage or death. Cesarean section is one of the safest operations in the world, but several hundred cesarean sections to prevent one bad outcome seems excessive to me although others may legitimately disagree and the mother may consider this a reasonable tradeoff. If ane believes, for example, that all breech presenting fetuses in labor should exist delivered by cesarean department and then one is implicitly accepting that doing several hundred cesarean sections to prevent one bad consequence is reasonable. Similarly, in a suitably chosen woman who is attempting a trial of labor later cesarean, the chance of a major ending, namely, expiry or damage to the infant, is virtually 1 in 1,000 attempts. We let women to choose elective repeat cesarean section for such a small take chances; one and then has to accede to a woman's request for an elective cesarean department if the babe is thought to be besides large.

Ane interesting endeavour to endeavour to better predict those instances where shoulder dystocia with injury might occur has been proposed.^xvi The model essentially takes the estimated fetal weight with the maternal weight and height and calculates a risk of shoulder dystocia with injury. In this model, to prevent one case of shoulder dystocia with brachial plexus injury, I estimated that 27 extra cesarean sections would have to exist performed. If one assumes that xx% of those injuries would be permanent, it comes to 135 actress cesarean sections to preclude a permanent injury. The model is promising, just however one is doing many cesarean sections to prevent one bad event.

A final approach to reducing the hazard of macrosomia and shoulder dystocia is to induce labor early on if the infant is thought to be getting too big. One prospective study has addressed the question of labor induction to prevent shoulder dystocia.¹⁷ Instead of waiting to induce labor when the fetus was already thought to be 4 kg or more, consecration was carried out between 36 and 39 weeks when the fetus was thought to be large clinically and on ultrasound. The authors demonstrated that the induction of labor group had a lower cesarean section rate (28% vs 32%) and that the rate of shoulder dystocia of whatsoever blazon was 4% vs 8%. In the induction grouping, the mean nascency weight was about 300 yard less. At first look, the results are impressive. Disconcerting, however, is that despite the fact that less than half the babies weighed over 4 kg and <10% were more than 4,500 yard, notwithstanding, the overall cesarean department charge per unit in the study was 30%. In a study carried out in my hospital 25 years ago¹⁸ where all babies had a birthweight of 4,500 g or more, the cesarean section rate in women without a previous cesarean section was merely over xx%. The problem with ultrasound estimation of fetal weight is that if one tells the obstetrician or the pregnant woman that the fetus may be big, that noesis by itself will bias people to perform a cesarean section, either before labor or during labor if labor is going slower than expected.

Management of shoulder dystocia

General considerations

If there is worry that the fetus might be macrosomic, or that there is an otherwise increased gamble of shoulder dystocia, for example, a mid-cavity delivery afterwards a long second stage, or if the woman is obese and has diabetes, then commitment should not be in the same room where labor occurred. Delivery should be in an operating room. If serious shoulder dystocia is encountered and one has to consider a full general anesthetic or complicated obstetrical maneuvers you exercise not want to be wasting valuable minutes going from a birthing room to an operating room.

Unless ane is doing an operative vaginal delivery for the head (in which case one has no choice) the lower end of the bed should non be broken. This tempts the accoucheur to pull downward on the head to deliver the shoulders. Go out the bed unbroken. One should not pull on the head at all. If the shoulders have not delivered with the same contraction as the caput, I prefer to wait for the next contraction in almost all circumstances. Information technology may take 2–3 minutes for the next contraction to come and it is unnerving for those who have become accepted to aiming for delivery of the shoulders correct later the head. When the adjacent contraction comes, the mother is encouraged to button strongly and it may take 3–iv pushes during the contraction for delivery of the shoulders. Ane should avoid pulling on the head.

One legitimate business and an unsettled outcome is the following: if there is an apprehension that shoulder dystocia may occur and if, indeed, this turns out to exist a case of genuine shoulder dystocia then one has lost 2–iii valuable minutes in waiting that could have been used to effort and resolve the shoulder dystocia. This is a downside of waiting for shoulders.

In certain circumstances, the delivery of the head can requite clues as to whether 1 might be dealing with shoulder dystocia. If, subsequently commitment of the caput, with or without instruments, the face and chin are delivered with difficulty, the mentum has to be hooked over the perineum, or the perineum has to be pushed dorsum to allow the mentum to evangelize, or later the head has delivered the head is sucked back against the vulva and does not restitute at all, if these weather condition apply, it is probably not a proficient thought to await 2–three minutes for the next contraction before asking the female parent to push vigorously. If with vigorous maternal pushing the female parent cannot push the shoulders out, then the diagnosis of shoulder dystocia tin be made. But there should be no pulling on the baby'south caput.

One time the diagnosis of shoulder dystocia is anticipated or is made, extra help should exist summoned, including an anesthesiologist if not already washed beforehand, the bed should exist broken, and the mother's buttocks brought downwardly beyond the edge of the tabular array, and the hips should exist flexed so that the knees are close to the mother's chest. This is the and then-chosen McRoberts' position.

The McRoberts' position has advantages. The first is that in some instances sharply flexing the mother'south legs against her chest will movement the symphysis pubis over the anterior shoulder helping to dislodge it. The other is that the position may allow the posterior shoulder to slide downwardly further into the sacral hollow and make access to the posterior arm and shoulder easier. The McRoberts' position is fine; the problem is with McRoberts' maneuver. After the McRoberts' position is adopted, the usual advice is for the delivering obstetrician to now pull on the infant's head in concert with maternal pushing. Indeed, some other purported reward given for the McRoberts' maneuver is that the traction forces are less than when the mother is not in McRoberts' position. The adjacent step described is to apply suprapubic pressure on the stuck anterior shoulder to try to dislodge the shoulder from behind the symphysis pubis. This maneuver is besides followed with traction on the head.

The guidelines of the expert bodies (the American,^six the British,⁷ and the French^nineteen) all endorse the McRoberts' maneuver with or without suprapubic pressure every bit the beginning-line treatment for the management of shoulder dystocia. I disagree. The reported success rates with these maneuvers as commencement-line measures is about 50%, with higher success rates more often than not in the reports with the highest incidences of shoulder dystocia. Who can argue with this? The trouble is that when one looks at reports^20–23 of brachial plexus injury when the only maneuvers that have been used are the McRoberts' maneuver, with or without suprapubic pressure, in that location is about a 10% incidence of brachial plexus injury. The fact is that in the usual instance of shoulder dystocia in that location have often been at to the lowest degree iii traction efforts on the baby'due south caput, namely, the first downward traction used to diagnose shoulder dystocia and then a second downward traction attempt with the McRoberts' maneuver, and a third traction attempt with the suprapubic pressure maneuvers.

The defence of using the McRoberts' maneuver and suprapubic pressure level as first-line handling is that they are easy to perform and that they often resolve the shoulder dystocia. The further defense force is that when comparison is made with the incidence of brachial plexus injury when the other standard maneuvers are used, such equally rotation of the shoulders or delivery of the posterior or anterior arm, the rate of brachial plexus injury seems to exist the same. What is not emphasized, however, is that recourse to the other standard maneuvers is almost invariably made afterwards there have been failed attempts with McRoberts' maneuver and/or suprapubic pressure. Every bit rotation maneuvers and direct arm extraction maneuvers practice non cause lateral traction on the brachial plexus, most such injuries are almost certainly a upshot of the initial downwards traction used to diagnose shoulder dystocia or to the traction attempts during the McRoberts'/suprapubic combination or to upward traction on the fetal head to attempt to free the posterior shoulder. McRoberts' position is expert; McRoberts' maneuver, if that involves traction, is bad.

A final consideration: information technology is imperative that 1 avoid cutting whatsoever nuchal cord before commitment. If shoulder dystocia occurs it is a disaster.^24,25

Specific maneuvers

So the diagnosis of shoulder dystocia has been fabricated by the inability of the mother to push the shoulders out by her own efforts and even after the McRoberts' position has been employed. What is the adjacent stride? The next step is to put 1's dominant hand into the posterior part of the pelvis and determine if the posterior shoulder is in the sacral concavity or not.

Almost ever, the posterior shoulder has gotten by the sacral promontory and is present somewhere along the curve of the sacrum. This volition virtually always be resolvable with the standard obstetrical maneuvers. There are two standard approaches, the rotational maneuvers and the arm extraction maneuvers.

In the rotational maneuvers, the best approach is to employ ane's ascendant hand (non only two fingers) and introduce the palm of the hand into the 6 o'clock position in the pelvis behind the shoulder, as if applying the first forceps blade in a forceps commitment, and then move that mitt to the left side (for right handers) of the mother's pelvis. The mitt will now be either at the anterior part of the posterior shoulder or the posterior part of the posterior shoulder. If it is the anterior surface of the posterior shoulder that i'due south hand is against, ane will now try to rotate the posterior shoulder clockwise in gild to corkscrew the shoulders through the pelvis. This is the only time when some fundal pressure may exist allowed, although it has to be nether the direction and coordination of the obstetrician. If it works, the posterior shoulder will rotate around so that it lies nether the symphysis pubis and the previous anterior shoulder will at present be in the hollow of the sacrum and delivery should continue smoothly after that. This is the Woods spiral maneuver.²⁶

If it is the baby'southward left shoulder that is lying posteriorly in the sacral hollow, and then when the obstetrician puts his ascendant hand into the left side of the maternal pelvis, the paw volition be confronting the posterior aspect of the posterior shoulder. Now, once again, clockwise rotation attempts are made and can be synchronized with attempts to push the stuck anterior shoulder dorsally to the female parent'due south left. This is the opposite Woods maneuver that was described by Rubin.²⁷ One tin can of course attempt to rotate the shoulders counter clockwise, but, unless one is left handed, the left paw is not as effective in causing rotation.

If the rotation maneuvers do non work, one should go along to try to excerpt one of the artillery. This was the neat insight of Jacquemier²⁸ in 1860. The idea is that if one can extract one of the arms then one tin can convert the obstructing diameter from a biacromial diameter to an acromial-axillary diameter thereby reducing the biacromial width past the ii–three cm width of one shoulder.

Unremarkably, the anterior arm is likewise hard to reach behind the subpubic arch with the shoulder impacted against the symphysis pubis. All the same, information technology is worth trying a Couder maneuver^29,30 to see if it will work. This involves taking the index and middle fingers of one manus and, using them as a splint, try to place them on the anterior surface of the upper humerus. These two fingers now endeavour to button the humerus backward toward the baby'southward back and this will sometimes flex the elbow and let the paw announced under the symphysis. The hand tin can now be grasped and the anterior arm delivered.

The usual approach is to endeavour to evangelize the posterior arm showtime. This was described in English by Barnum¹⁰ and is described in all of the textbooks. The operator follows the shoulder to the humerus and hopes to notice the elbow and forearm of the posterior arm lying over the baby'southward breast and, once again, one grasps the forearm and sweeps information technology across the babe'southward chest and outside the vulva. Generally one time the posterior arm and shoulder take delivered, the inductive shoulder will fall beneath the symphysis pubis and be hands delivered. If the anterior shoulder does not follow, one can endeavor a Couder maneuver again or, using the delivered posterior arm, rotate the baby so that the anterior shoulder ends up in the posterior pelvis where it can be delivered. I should non pull on the head.

When commitment of the posterior arm fails, it is because the posterior arm is non lying across the fetal chest but is lying extended under the baby'southward body with the forearm and hand unreachable. This is where posterior axillary traction should be used.^31,32 It is my preferred approach to all cases where the posterior shoulder is in the sacral concavity. This involves not extracting the posterior arm first but delivering the posterior shoulder first. I puts the middle fingers (not index fingers – they are not strong enough) into the axilla like hooks and pull down the posterior shoulder with the overlapping fingers. Ideally an assistant is tilting (not pulling) the baby's head upward. The operator should exist on his knees. One pulls the posterior shoulder downwards using traction with the overlapping middle fingers in the axilla. I should not pull parallel to the flooring, only instead drag the posterior shoulder along the curve of the sacrum until the posterior shoulder and then arm emerge. This is past no means a novel technique. In fact, it was described in 1609 past the purple midwife Louise Conservative. In Jacquemier's treatise on shoulder dystocia, the technique is often described. English-language textbooks did not describe information technology in the past because of concern that the fingers in the posterior axilla could somehow damage the brachial plexus past direct force per unit area (a theory proposed by Erb), but this fear is unfounded.

On very rare occasions, the two middle fingers together cannot pull the posterior shoulder downwards and it is necessary to pass a strong, thin nonstretchable cord or catheter effectually the axilla to hook it then pull downward on the cord with a Kocher clench.³³ Ane can also impart rotation with this approach. Almost invariably once the posterior shoulder and arm are delivered, the anterior shoulder volition release itself from the symphysis pubis. If not, 1 must resist the temptation to pull down on the head. Instead, utilize a Couder maneuver to free the anterior arm or rotate the babe by the arm 180°.

The apprehension that some take with delivering the posterior arm and, especially, the posterior shoulder directly is the high risk (in my experience, about one in four) of fracturing the humerus. In many manufactures, fractured humeri and brachial plexus injuries are lumped together as birth trauma, merely the comparison makes no sense. Fractured humeri always heal. There is never permanent injury. A permanent brachial plexus injury is a serious lifelong inability.

What if shoulder dystocia is diagnosed and the vaginal hand shows that the posterior shoulder is non in the pelvis, that is, the posterior shoulder is caught up above the sacral promontory, in other words, there is a double shoulder dystocia? 1 has a big problem.

The classic approach is to use the Jacquemier'southward maneuver described in 1860.²⁸ Information technology is substantially trying to evangelize the posterior arm, but unlike in some respects from when the posterior shoulder is already in the sacral hollow. Delivery of the posterior arm when the posterior shoulder is to a higher place the sacral promontory is virtually never described in English-language textbooks or articles. The best descriptions, with illustrations, are in Italian and French textbooks.^34,35

The mother's hips are by the edge of the bed. The operator is on i knee in front of the patient. The paw that volition be used is the 1 that corresponds to the baby's abdomen. If it is the baby's right shoulder that is posterior, the operator's right hand is used. If it is the baby's left shoulder that is posterior it is the operator's left hand that is used. The operator uses his gloved hand only the forearm is blank and well lubricated so every bit to reduce the friction of a gown when the forearm up until the elbow is inside the vagina. The operator is on one knee considering the forearm has to follow the maternal axis from the coccyx to the omphalos. Getting the forearm into the pelvis and past the sacral promontory is not hard considering the pelvis is empty apart from the baby's neck. The hand and lower forearm are passed beyond the pelvic inlet and one seeks to observe the baby's forearm and bring down that arm. Delivery is generally straightforward after this. In centers experienced in the technique, information technology succeeds more than nine times out of ten.³⁶

Another technique described (with which I have no personal experience) is the Letellier maneuver,^34,35 which aims to deliver the posterior shoulder trapped above the sacral promontory. This fourth dimension ane uses the mitt corresponding to the fetal dorsum (right paw for the left shoulder, left paw for the right shoulder). 1 reaches upwardly and tries to claw the alphabetize finger into the posterior function of the axilla and the thumb in the anterior role of the axilla. Instead of trying to pull the posterior shoulder directly downward the posterior shoulder is pushed in the direction of the pubis while simultaneously rotating it along the pelvic brim. If i is fortunate, the posterior shoulder can be rotated under the pubis and that arm brought down.

If after three–four minutes the Jacquemier±Letellier maneuvers have failed or else one has been able to deliver the posterior arm and yet the shoulder dystocia cannot be resolved, one is now faced with a catastrophic shoulder dystocia and something drastic has to be done.

The procedure most described is to attempt to push the already delivered head back into the vagina and go on to do a cesarean section. The bulk of the time this is described as easy and if indeed the head does enter the vagina easily and a quick cesarean section can be done so this is probably the best style to go along. In cases where cephalic replacement has been unsuccessful, there are descriptions of doing hysterotomies and through the hysterotomy trying to dislodge the stuck anterior shoulder or else trying to pass the stuck posterior shoulder from to a higher place into the sacral hollow to be delivered by an assistant from the vagina. I accept no personal feel with either method.

To me the best solution is to proceed with a symphysiotomy. Whenever one is anticipating the possibility of shoulder dystocia one should be physically and psychologically prepared to proceed with symphysiotomy. A iii cm separation of the symphysis pubis will enlarge the diameter of the pelvic inlet by some 25%³⁷ and resolve every case of shoulder dystocia. A Foley catheter should be left in place or, alternatively, be inserted if shoulder dystocia is more than than a remote possibility. Trying to insert a catheter through the urethra when the head has already delivered and the shoulders are stuck is difficult. A scalpel should be at manus. If an anesthesiologist is not already present to put the adult female to sleep or if the epidural coldhearted has not been topped up, the mons veneris over the symphysis pubis and the underlying symphysis ligament should be infiltrated with xylocaine.

Rubin²⁷ proposed symphysiotomy every bit a desperate measure in his article on shoulder dystocia. There are about a dozen cases published of symphysiotomy done for shoulder dystocia. In every single case where symphysiotomy was washed, there was immediate commitment of the body. Even so, the result is not uniformly good for the baby. The process has been described as "too little, likewise late" just only the "too late" function is correct. The 25% enlargement of the pelvic inlet always allows piece of cake delivery of the shoulders. However, the procedure must be done promptly. In the iii cases described in one commodity,³⁸ the procedures were washed 12 minutes, 13 minutes, and 23 minutes after commitment of the head, and of course all the outcomes were bad. In some other report²⁵ of two cases, there was again immediate delivery of the body, but one outcome was bad considering a nuchal cord had been clamped and cut earlier shoulder dystocia was recognized. As has been stated in using symphysiotomy for the trapped after-coming head of a breech, waiting too long to do a symphysiotomy merely facilitates the delivery of a dead or brain-damaged baby.³⁷ The best description of the technique, with pictures, is that of Grand. Mola.³⁹ I caveat with symphysiotomy is to never let the vaginal heart finger deviate from its position nether the symphysis. The urethra and, more importantly, the fetal cervix are located under the symphysis.

There is no clear cutting time limit as to how fast one should attempt to resolve shoulder dystocia simply after four–5 minutes of trying other maneuvers without success, one should be thinking nearly symphysiotomy. It does non neglect in resolving shoulder dystocia. It always works.

The legitimate argument volition be proposed that information technology is much better to have performed the several hundred elective cesarean sections necessary to foreclose a permanent injury from shoulder dystocia for the baby rather than find oneself in the situation of having to perform a symphysiotomy. There is no doubt whatsoever that the woman recovering from a symphysiotomy volition be more miserable for 2–three weeks than the woman who has had an elective cesarean department instead. But the proper comparison is not between one symphysiotomy and one cesarean section. The proper comparison is the morbidity from one symphysiotomy vs the several hundred needless cesarean sections, allow alone the subsequent repeats, to preclude 1 symphysiotomy. It is the aforementioned dilemma with vaginal breech delivery. To prevent i catastrophe in a vaginally born breech baby, you have to do several hundred cesarean sections. I have always felt that anybody who is going to undertake vaginal breech commitment should e'er be physically and psychologically prepared to perform a symphysiotomy if the need arises. The same applies to shoulder dystocia.

Resuscitating the baby later shoulder dystocia

After the obstetrician or midwife has finally succeeded in resolving a shoulder dystocia, after swell stress and anxiety, and a limp, depressed baby is born, and the neonatal team is anxiously waiting to resuscitate the babe, in that location is an inevitable natural trend to immediately clamp and cutting the umbilical string so as to paw the baby over to the waiting resuscitators. This is the wrong affair to practise. Fifty-fifty if the shoulder dystocia has taken less than v minutes to resolve, some babies come out without a pulse and cannot be resuscitated.⁴⁰ The problem is not lack of oxygen. Expert resuscitators should be able to resuscitate without subsequent brain damage babies born after 5–10 minutes of complete uterine rupture or abruptio placenta or sudden unexplained bradycardia. The deviation with the depressed baby after shoulder dystocia is that in add-on to interruption of oxygen supply, the babe may besides be severely hypovolemic.^11,41 While the baby's chest has been severely compressed within the pelvis, the babe'south heart has been able to pump blood through the umbilical arteries into the placenta; yet, because of the chest compression or umbilical vein pinch, placental claret cannot render back to the chest. The worst thing when the baby comes out limp is to immediately clamp the cord. The resuscitators should come up to the babe instead of the baby being taken to the resuscitators. A minute or and so should be immune for the fetal blood accumulated in the placenta to return back to the baby's apportionment.

Decision

1. Shoulder dystocia is a serious emergency. If it is not resolved, the babe can die or be brain damaged. If one acts impetuously and pulls on the head, the brachial plexus tin be permanently injured.
2. The admonition has been fabricated "practice non pull hard, do not pull quickly, and do not pull down." I believe that one should not pull AT ALL, neither to make the diagnosis of shoulder dystocia nor as function of the McRoberts' maneuver or in conjunction with suprapubic pressure.
3. If the fetus is macrosomic or the mother is obese or diabetic, delivery should not take identify in a birthing room but rather in an operating room.
4. Exercise not clamp and cutting a nuchal cord.
5. Be prepared for the worst, including the need for symphysiotomy and general anesthesia.
6. Shoulder dystocia is diagnosed when the mother cannot push the shoulders out with the subsequent contraction. If an urgent vacuum or forceps delivery has been done for severe bradycardia or a terrible tracing, or if at that place is a strong presumption of shoulder dystocia because the mentum is tight against the vulva, practise not look until the next contraction.
7. McRoberts' position is fine; McRoberts' maneuver, pulling on the head, is not.
8. Put your hand in the vagina and detect out if the posterior shoulder is in the sacral hollow or not.
9. If the posterior shoulder is in the sacral hollow, the almost effective approach is to utilize posterior axillary traction, either with overlapping middle fingers or with a sling, and drag the shoulder forth the sacral hollow until the shoulder and arm are delivered. The humerus will often fracture. This is unfortunate but not disastrous. Dozens of fractured humeri are better than one permanent brachial plexus injury with a useless arm.
10. If the posterior shoulder is not in the sacral hollow but is at the pelvic brim, the all-time maneuver is the Jacquemier maneuver and properly performed volition almost always work.
11. If after five minutes or then, the shoulder dystocia has not been resolved, try to push the delivered caput dorsum into the vagina and if information technology goes in easily proceed to a cesarean section. If the head cannot be replaced hands, proceed to a symphysiotomy. Others would go along to symphysiotomy instead of trying to supercede the head.
12. After the babe is born, do not immediately clench and cut the umbilical cord. Permit a minute become by and so that the babe can be autotransfused through the placenta and have the infant resuscitators start their resuscitating at the female parent's bedside.

Disclosure

The writer reports no conflict of interest in this work. The author would like to disclose that as the patients take been lost to follow-upwardly, patient written informed consent for publication of these case details was not possible. The details accept been sufficiently anonymized as not to crusade harm to the patient.

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