podalic presentation of fetus

7.8 Internal version

Manual intrauterine procedure to convert one presentation to another, usually a transverse lie into a breech.

7.8.1 Indications and conditions

• Shoulder presentation during labour, at complete dilation with a relaxed uterus. This manoeuvre should be performed with extreme caution (risk of uterine rupture).
• Delivery of a second twin in cephalic presentation or transverse lie: version to bring the foetus into the breech position and allow a total breech extraction (Chapter 6, Section 6.3 ).
• Conditions necessary in all cases: normal pelvis, presenting part not engaged, bladder empty.
• Grasping one or both feet is best done through membranes that have been left intact [1] Citation 1. J Rabinovici, G Barkai, B Reichman, D M Serr, S Mashiach. Internal podalic version with unruptured membranes for the second twin in transverse lie. Obstetrics and Gynecology; 1988; 71(3 Pt 1):428-30. .

7.8.2 Technique

• Strict asepsis: swab perineum with 10% povidone iodine, wear sterile gloves.
• Perform spinal anaesthesia if possible.
• with the fingers in the form of a cone, go through the vaginal opening and the cervix toward the fundus;
• hold the fundus in place with the other hand on the abdomen.
• Grasp one foot or, if possible, both feet, firmly, without haste but not too slowly, since a prolonged manoeuvre might cause the uterus to contract (Figure 7.3a). It is better not to rupture the membranes immediately because the uterine retraction and lack of amniotic fluid will make it difficult to grasp and move the foetus. The membranes will spontaneously rupture when pulling the foot or will be artificially ruptured once the foot is down.
• Pull the foot/feet gently to the vaginal opening (Figure 7.3b).
• The delivery then continues normally as a breech delivery. For the second twin proceed with total breech extraction (Chapter 6, Section 6.3 ).
• Manually explore the uterus after delivery of the placenta (to look for uterine rupture), and administer routinely antibiotic prophylaxis ( cefazolin or ampicillin slow IV: 2 g single dose) a Citation a. For patients with a history of immediate hypersensitivity reaction to penicillin (urticaria, respiratory problems or oedema): clindamycin IV 900 mg single dose + gentamicin IV 5 mg/kg single dose. .

Figures 7.3 - Internal version

7.3a  - Catch hold of one foot (preferably both feet)

7.3b  - Bring the foot/feet down to the vaginal opening

• (a) For patients with a history of immediate hypersensitivity reaction to penicillin (urticaria, respiratory problems or oedema): clindamycin IV 900 mg single dose + gentamicin IV 5 mg/kg single dose.
• 1. J Rabinovici, G Barkai, B Reichman, D M Serr, S Mashiach. Internal podalic version with unruptured membranes for the second twin in transverse lie. Obstetrics and Gynecology; 1988; 71(3 Pt 1):428-30.

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Normal Labor

Fetal Lie The relation of the fetal long axis to that of the mother is termed fetal lie and is either longitudinal or transverse . Occasionally, the fetal and the maternal axes may cross at a 45-degree angle, forming an oblique lie . This lie is unstable and becomes longitudinal or transverse during labor. A longitudinal lie is present in more than 99 percent of labors at term. Predisposing factors for transverse fetal position include multiparity, placenta previa, hydramnios, and uterine anomalies ( Chap. 23 , p. 468 ). Fetal Presentation The presenting part is that portion of the fetal body that is either foremost within the birth canal or in closest proximity to it. It typically can be felt through the cervix on vaginal examination. Accordingly, in longitudinal lies, the presenting part is either the fetal head or breech, creating cephalic and breech presentations , respectively. When the fetus lies with the long axis transversely, the shoulder is the presenting part. Table 22-1 describes the incidences of the various fetal presentations. TABLE 22-1. Fetal Presentation in 68,097 Singleton Pregnancies at Parkland Hospital Cephalic Presentation Such presentations are classified according to the relationship between the head and body of the fetus ( Fig. 22-1 ). Ordinarily, the head is flexed sharply so that the chin is in contact with the thorax. The occipital fontanel is the presenting part, and this presentation is referred to as a vertex or occiput presentation . Much less commonly, the fetal neck may be sharply extended so that the occiput and back come in contact, and the face is foremost in the birth canal— face presentation ( Fig. 23-6 , p. 466 ). The fetal head may assume a position between these extremes, partially flexed in some cases, with the anterior (large) fontanel, or bregma, presenting— sinciput presentation —or partially extended in other cases, to have a brow presentation ( Fig. 23-8 , p. 468 ). These latter two presentations are usually transient. As labor progresses, sinciput and brow presentations almost always convert into vertex or face presentations by neck flexion or extension, respectively. Failure to do so can lead to dystocia, as discussed in Chapter 23 ( p. 455 ). Figure 22-1 Longitudinal lie. Cephalic presentation. Differences in attitude of the fetal body in (A) vertex, (B) sinciput, (C) brow, and (D) face presentations. Note changes in fetal attitude in relation to fetal vertex as the fetal head becomes less flexed. The term fetus usually presents with the vertex, most logically because the uterus is piriform or pear shaped. Although the fetal head at term is slightly larger than the breech, the entire podalic pole of the fetus—that is, the breech and its flexed extremities—is bulkier and more mobile than the cephalic pole. The cephalic pole is composed of the fetal head only. Until approximately 32 weeks, the amnionic cavity is large compared with the fetal mass, and the fetus is not crowded by the uterine walls. Subsequently, however, the ratio of amnionic fluid volume decreases relative to the increasing fetal mass. As a result, the uterine walls are apposed more closely to the fetal parts. If presenting by the breech, the fetus often changes polarity to make use of the roomier fundus for its bulkier and more mobile podalic pole. As discussed in Chapter 28 ( p. 559 ), the incidence of breech presentation decreases with gestational age. It approximates 25 percent at 28 weeks, 17 percent at 30 weeks, 11 percent at 32 weeks, and then decreases to approximately 3 percent at term. The high incidence of breech presentation in hydrocephalic fetuses is in accord with this theory, as the larger fetal cephalic pole requires more room than its podalic pole. Breech Presentation When the fetus presents as a breech, the three general configurations are frank, complete , and footling presentations and are described in Chapter 28 ( p. 559 ). Breech presentation may result from circumstances that prevent normal version from taking place. One example is a septum that protrudes into the uterine cavity ( Chap. 3 , p. 42 ). A peculiarity of fetal attitude, particularly extension of the vertebral column as seen in frank breeches, also may prevent the fetus from turning. If the placenta is implanted in the lower uterine segment, it may distort normal intrauterine anatomy and result in a breech presentation. Fetal Attitude or Posture In the later months of pregnancy, the fetus assumes a characteristic posture described as attitude or habitus as shown in Figure 22-1 . As a rule, the fetus forms an ovoid mass that corresponds roughly to the shape of the uterine cavity. The fetus becomes folded or bent upon itself in such a manner that the back becomes markedly convex; the head is sharply flexed so that the chin is almost in contact with the chest; the thighs are flexed over the abdomen; and the legs are bent at the knees. In all cephalic presentations, the arms are usually crossed over the thorax or become parallel to the sides. The umbilical cord lies in the space between them and the lower extremities. This characteristic posture results from the mode of fetal growth and its accommodation to the uterine cavity. Abnormal exceptions to this attitude occur as the fetal head becomes progressively more extended from the vertex to the face presentation (see Fig. 22-1 ). This results in a progressive change in fetal attitude from a convex (flexed) to a concave (extended) contour of the vertebral column. Fetal Position Position refers to the relationship of an arbitrarily chosen portion of the fetal presenting part to the right or left side of the birth canal. Accordingly, with each presentation there may be two positions—right or left. The fetal occiput, chin (mentum), and sacrum are the determining points in vertex, face, and breech presentations, respectively ( Figs. 22-2 to 22-6 ). Because the presenting part may be in either the left or right position, there are left and right occipital, left and right mental, and left and right sacral presentations. These are abbreviated as LO and RO, LM and RM, and LS and RS, respectively. FIGURE 22-2 Longitudinal lie. Vertex presentation. A. Left occiput anterior (LOA). B. Left occiput posterior (LOP). FIGURE 22-3 Longitudinal lie. Vertex presentation. A . Right occiput posterior (ROP). B . Right occiput transverse (ROT). FIGURE 22-4 Longitudinal lie. Vertex presentation. Right occiput anterior (ROA). FIGURE 22-5 Longitudinal lie. Face presentation. Left and right mentum anterior and right mentum posterior positions. FIGURE 22-6 Longitudinal lie. Breech presentation. Left sacrum posterior (LSP). Varieties of Presentations and Positions For still more accurate orientation, the relationship of a given portion of the presenting part to the anterior, transverse, or posterior portion of the maternal pelvis is considered. Because the presenting part in right or left positions may be directed anteriorly (A), transversely (T), or posteriorly (P), there are six varieties of each of the three presentations as shown in Figures 22-2 to 22-6 . Thus, in an occiput presentation, the presentation, position, and variety may be abbreviated in clockwise fashion as: Approximately two thirds of all vertex presentations are in the left occiput position, and one third in the right. In shoulder presentations, the acromion (scapula) is the portion of the fetus arbitrarily chosen for orientation with the maternal pelvis. One example of the terminology sometimes employed for this purpose is illustrated in Figure 22-7 . The acromion or back of the fetus may be directed either posteriorly or anteriorly and superiorly or inferiorly. Because it is impossible to differentiate exactly the several varieties of shoulder presentation by clinical examination and because such specific differentiation serves no practical purpose, it is customary to refer to all transverse lies simply as shoulder presentations . Another term used is transverse lie , with back up or back down , which is clinically important when deciding incision type for cesarean delivery ( Chap. 23 , p. 468 ). FIGURE 22-7 Transverse lie. Right acromiodorsoposterior (RADP). The shoulder of the fetus is to the mother’s right, and the back is posterior. Diagnosis of Fetal Presentation and Position Several methods can be used to diagnose fetal presentation and position. These include abdominal palpation, vaginal examination, auscultation, and, in certain doubtful cases, sonography. Rarely, plain radiographs, computed tomography, or magnetic resonance imaging may be used. Abdominal Palpation—Leopold Maneuvers Abdominal examination can be conducted systematically employing the four maneuvers described by Leopold in 1894 and shown in Figure 22-8 . The mother lies supine and comfortably positioned with her abdomen bared. These maneuvers may be difficult if not impossible to perform and interpret if the patient is obese, if there is excessive amnionic fluid, or if the placenta is anteriorly implanted. FIGURE 22-8 Leopold maneuvers (A–D) performed in a fetus with a longitudinal lie in the left occiput anterior position (LOA). The first maneuver permits identification of which fetal pole—that is, cephalic or podalic—occupies the uterine fundus. The breech gives the sensation of a large, nodular mass, whereas the head feels hard and round and is more mobile and ballottable. Performed after determination of fetal lie, the second maneuver is accomplished as the palms are placed on either side of the maternal abdomen, and gentle but deep pressure is exerted. On one side, a hard, resistant structure is felt—the back. On the other, numerous small, irregular, mobile parts are felt—the fetal extremities. By noting whether the back is directed anteriorly, transversely, or posteriorly, fetal orientation can be determined. The third maneuver is performed by grasping with the thumb and fingers of one hand the lower portion of the maternal abdomen just above the symphysis pubis. If the presenting part is not engaged, a movable mass will be felt, usually the head. The differentiation between head and breech is made as in the first maneuver. If the presenting part is deeply engaged, however, the findings from this maneuver are simply indicative that the lower fetal pole is in the pelvis, and details are then defined by the fourth maneuver. To perform the fourth maneuver, the examiner faces the mother’s feet and, with the tips of the first three fingers of each hand, exerts deep pressure in the direction of the axis of the pelvic inlet. In many instances, when the head has descended into the pelvis, the anterior shoulder may be differentiated readily by the third maneuver. Abdominal palpation can be performed throughout the latter months of pregnancy and during and between the contractions of labor. With experience, it is possible to estimate the size of the fetus. According to Lydon-Rochelle and colleagues (1993), experienced clinicians accurately identify fetal malpresentation using Leopold maneuvers with a high sensitivity—88 percent, specificity—94 percent, positive-predictive value—74 percent, and negative-predictive value—97 percent. Vaginal Examination Before labor, the diagnosis of fetal presentation and position by vaginal examination is often inconclusive because the presenting part must be palpated through a closed cervix and lower uterine segment. With the onset of labor and after cervical dilatation, vertex presentations and their positions are recognized by palpation of the various fetal sutures and fontanels. Face and breech presentations are identified by palpation of facial features and fetal sacrum, respectively. In attempting to determine presentation and position by vaginal examination, it is advisable to pursue a definite routine, comprising four movements. First, the examiner inserts two fingers into the vagina and the presenting part is found. Differentiation of vertex, face, and breech is then accomplished readily. Second, if the vertex is presenting, the fingers are directed posteriorly and then swept forward over the fetal head toward the maternal symphysis ( Fig. 22-9 ). During this movement, the fingers necessarily cross the sagittal suture and its linear course is delineated. Next, the positions of the two fontanels are ascertained. For this, fingers are passed to the most anterior extension of the sagittal suture, and the fontanel encountered there is examined and identified. Then, with a sweeping motion, the fingers pass along the suture to the other end of the head until the other fontanel is felt and differentiated ( Fig. 22-10 ). Last, the station, or extent to which the presenting part has descended into the pelvis, can also be established at this time ( p. 449 ). Using these maneuvers, the various sutures and fontanels are located readily ( Fig. 7-11 , p. 139 ). FIGURE 22-9 Locating the sagittal suture by vaginal examination. FIGURE 22-10 Differentiating the fontanels by vaginal examination. Sonography and Radiography Sonographic techniques can aid fetal position identification, especially in obese women or in women with rigid abdominal walls. Zahalka and associates (2005) compared digital examinations with transvaginal and transabdominal sonography for fetal head position determination during second-stage labor and reported that transvaginal sonography was superior. Occiput Anterior Presentation In most cases, the vertex enters the pelvis with the sagittal suture lying in the transverse pelvic diameter. The fetus enters the pelvis in the left occiput transverse (LOT) position in 40 percent of labors and in the right occiput transverse (ROT) position in 20 percent (Caldwell, 1934). In occiput anterior positions—LOA or ROA— the head either enters the pelvis with the occiput rotated 45 degrees anteriorly from the transverse position, or this rotation occurs subsequently. The mechanism of labor in all these presentations is usually similar. The positional changes of the presenting part required to navigate the pelvic canal constitute the mechanisms of labor . The cardinal movements of labor are engagement, descent, flexion, internal rotation, extension, external rotation, and expulsion ( Fig. 22-11 ). During labor, these movements not only are sequential but also show great temporal overlap. For example, as part of engagement, there is both flexion and descent of the head. It is impossible for the movements to be completed unless the presenting part descends simultaneously. Concomitantly, uterine contractions effect important modifications in fetal attitude, or habitus, especially after the head has descended into the pelvis. These changes consist principally of fetal straightening, with loss of dorsal convexity and closer application of the extremities to the body. As a result, the fetal ovoid is transformed into a cylinder, with the smallest possible cross section typically passing through the birth canal. Figure 22-11 Cardinal movements of labor and delivery from a left occiput anterior position. Engagement The mechanism by which the biparietal diameter—the greatest transverse diameter in an occiput presentation—passes through the pelvic inlet is designated engagement . The fetal head may engage during the last few weeks of pregnancy or not until after labor commencement. In many multiparous and some nulliparous women, the fetal head is freely movable above the pelvic inlet at labor onset. In this circumstance, the head is sometimes referred to as “floating.” A normal-sized head usually does not engage with its sagittal suture directed anteroposteriorly. Instead, the fetal head usually enters the pelvic inlet either transversely or obliquely. Segel and coworkers (2012) analyzed labor in 5341 nulliparous women and found that fetal head engagement before labor onset did not affect vaginal delivery rates in either spontaneous or induced labor. Asynclitism. The fetal head tends to accommodate to the transverse axis of the pelvic inlet, whereas the sagittal suture, while remaining parallel to that axis, may not lie exactly midway between the symphysis and the sacral promontory. The sagittal suture frequently is deflected either posteriorly toward the promontory or anteriorly toward the symphysis ( Fig. 22-12 ). Such lateral deflection to a more anterior or posterior position in the pelvis is called asynclitism . If the sagittal suture approaches the sacral promontory, more of the anterior parietal bone presents itself to the examining fingers, and the condition is called anterior asynclitism . If, however, the sagittal suture lies close to the symphysis, more of the posterior parietal bone will present, and the condition is called posterior asynclitism . With extreme posterior asynclitism, the posterior ear may be easily palpated. FIGURE 22-12 Synclitism and asynclitism. Moderate degrees of asynclitism are the rule in normal labor. However, if severe, the condition is a common reason for cephalopelvic disproportion even with an otherwise normal-sized pelvis. Successive shifting from posterior to anterior asynclitism aids descent. Descent This movement is the first requisite for birth of the newborn. In nulliparas, engagement may take place before the onset of labor, and further descent may not follow until the onset of the second stage. In multiparas, descent usually begins with engagement. Descent is brought about by one or more of four forces: (1) pressure of the amnionic fluid, (2) direct pressure of the fundus upon the breech with contractions, (3) bearing-down efforts of maternal abdominal muscles, and (4) extension and straightening of the fetal body. Flexion As soon as the descending head meets resistance, whether from the cervix, pelvic walls, or pelvic floor, it normally flexes. With this movement, the chin is brought into more intimate contact with the fetal thorax, and the appreciably shorter suboccipitobregmatic diameter is substituted for the longer occipitofrontal diameter ( Figs. 22-13 and 22-14 ). FIGURE 22-13 Lever action produces flexion of the head. Conversion from occipitofrontal to suboccipitobregmatic diameter typically reduces the anteroposterior diameter from nearly 12 to 9.5 cm. FIGURE 22-14 Four degrees of head flexion. The solid line represents the occipitomental diameter, whereas the broken line connects the center of the anterior fontanel with the posterior fontanel. A. Flexion poor. B. Flexion moderate. C. Flexion advanced. D. Flexion complete. Note that with complete flexion, the chin is on the chest. The suboccipitobregmatic diameter, the shortest anteroposterior diameter of the fetal head, is passing through the pelvic inlet. Internal Rotation This movement consists of a turning of the head in such a manner that the occiput gradually moves toward the symphysis pubis anteriorly from its original position or, less commonly, posteriorly toward the hollow of the sacrum ( Figs. 22-15 to 22-17 ). Internal rotation is essential for completion of labor, except when the fetus is unusually small. FIGURE 22-15 Mechanism of labor for the left occiput transverse position, lateral view. A. Engagement. B. After engagement, further descent. C. Descent and initial internal rotation. D. Rotation and extension. FIGURE 22-16 Mechanism of labor for left occiput anterior position. FIGURE 22-17 Mechanism of labor for right occiput posterior position showing anterior rotation. Calkins (1939) studied more than 5000 women in labor to ascertain the time of internal rotation. He concluded that in approximately two thirds, internal rotation is completed by the time the head reaches the pelvic floor; in about another fourth, internal rotation is completed shortly after the head reaches the pelvic floor; and in the remaining 5 percent, rotation does not take place. When the head fails to turn until reaching the pelvic floor, it typically rotates during the next one or two contractions in multiparas. In nulliparas, rotation usually occurs during the next three to five contractions. Extension After internal rotation, the sharply flexed head reaches the vulva and undergoes extension. If the sharply flexed head, on reaching the pelvic floor, did not extend but was driven farther downward, it would impinge on the posterior portion of the perineum and would eventually be forced through the perineal tissues. When the head presses on the pelvic floor, however, two forces come into play. The first force, exerted by the uterus, acts more posteriorly, and the second, supplied by the resistant pelvic floor and the symphysis, acts more anteriorly. The resultant vector is in the direction of the vulvar opening, thereby causing head extension. This brings the base of the occiput into direct contact with the inferior margin of the symphysis pubis (see Fig. 22-16 ). With progressive distention of the perineum and vaginal opening, an increasingly larger portion of the occiput gradually appears. The head is born as the occiput, bregma, forehead, nose, mouth, and finally the chin pass successively over the anterior margin of the perineum (see Fig. 22-17 ). Immediately after its delivery, the head drops downward so that the chin lies over the maternal anus. External Rotation The delivered head next undergoes restitution (see Fig. 22-11 ). If the occiput was originally directed toward the left, it rotates toward the left ischial tuberosity. If it was originally directed toward the right, the occiput rotates to the right. Restitution of the head to the oblique position is followed by external rotation completion to the transverse position. This movement corresponds to rotation of the fetal body and serves to bring its bisacromial diameter into relation with the anteroposterior diameter of the pelvic outlet. Thus, one shoulder is anterior behind the symphysis and the other is posterior. This movement apparently is brought about by the same pelvic factors that produced internal rotation of the head. Expulsion Almost immediately after external rotation, the anterior shoulder appears under the symphysis pubis, and the perineum soon becomes distended by the posterior shoulder. After delivery of the shoulders, the rest of the body quickly passes. Occiput Posterior Presentation In approximately 20 percent of labors, the fetus enters the pelvis in an occiput posterior (OP) position (Caldwell, 1934). The right occiput posterior (ROP) is slightly more common than the left (LOP). It appears likely from radiographic evidence that posterior positions are more often associated with a narrow forepelvis. They also are more commonly seen in association with anterior placentation (Gardberg, 1994a). In most occiput posterior presentations, the mechanism of labor is identical to that observed in the transverse and anterior varieties, except that the occiput has to internally rotate to the symphysis pubis through 135 degrees, instead of 90 and 45 degrees, respectively (see Fig. 22-17 ). Effective contractions, adequate head flexion, and average fetal size together permit most posteriorly positioned occiputs to rotate promptly as soon as they reach the pelvic floor, and labor is not lengthened appreciably. In perhaps 5 to 10 percent of cases, however, rotation may be incomplete or may not take place at all, especially if the fetus is large (Gardberg, 1994b). Poor contractions, faulty head flexion, or epidural analgesia, which diminishes abdominal muscular pushing and relaxes pelvic floor muscles, may predispose to incomplete rotation. If rotation is incomplete, transverse arrest may result. If no rotation toward the symphysis takes place, the occiput may remain in the direct occiput posterior position, a condition known as persistent occiput posterior . Both persistent occiput posterior and transverse arrest represent deviations from the normal mechanisms of labor and are considered further in Chapter 23 . Fetal Head Shape Changes Caput Succedaneum In vertex presentations, labor forces alter fetal head shape. In prolonged labors before complete cervical dilatation, the portion of the fetal scalp immediately over the cervical os becomes edematous ( Fig. 33-1 , p. 647 ). This swelling, known as the caput succedaneum , is shown in Figures 22-18 and 22-19 . It usually attains a thickness of only a few millimeters, but in prolonged labors it may be sufficiently extensive to prevent differentiation of the various sutures and fontanels. More commonly, the caput is formed when the head is in the lower portion of the birth canal and frequently only after the resistance of a rigid vaginal outlet is encountered. Because it develops over the most dependent area of the head, one may deduce the original fetal head position by noting the location of the caput succedaneum. FIGURE 22-18 Formation of caput succedaneum and head molding.

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• v.318(7192); 1999 May 1

ABC of labour care

Unusual presentations and positions and multiple pregnancy.

In the vast majority of deliveries near term the fetus presents by the head, with the best fit into the lower pelvis in the occipito-anterior position. However, although the head is presenting, it may be not in an occipito-anterior but in an occipito-posterior or transverse position. In a few cases the head is grossly deflexed so that the brow or even the face can present.

In other instances, it is not the head that is at the lower pole of the uterus but the buttocks, or breech (from the old English brec—breeches or buttocks). The fetus many even lie transversely so that no pole is in relation to the pelvic inlet. A fetus in this position is undeliverable vaginally; both transverse lies and breech presentations are much more common if the woman enters labour in the earlier weeks of pregnancy (22-28 weeks of gestation).

All these malpresentations and malpositions need careful diagnosis and skilful management.

Malpositions

Normal mechanism.

Usually the fetal head engages in the left (less commonly, right) occipito-anterior position and then undergoes a short rotation to be directly occipito-anterior in the mid-cavity.

Occipito-posterior position

This is the commonest malpresentation. The head engages in the left or right occipito-transverse position, and the occiput rotates posteriorly, rather than into the more favourable occipito-anterior position. The reasons for the malrotation are often unclear. A flat sacrum or a head that is poorly flexed may be responsible; alternatively, poor uterine contractions may not push the head down into the pelvis strongly enough to produce correct rotation; epidural analgesia might sometimes relax the pelvic floor to an extent that the fetal occiput sinks into it rather than being pushed to rotate in an anterior direction. The diagnosis is determined clinically by vaginal examination.

The best management is to await events, preparing the woman and staff for a long labour. Progress should be monitored by abdominal and vaginal assessment, and the mother’s condition should be watched closely. Good pain relief with an epidural and adequate hydration are required.

The mother may have an urge to push before full dilation, but the midwife should discourage this. If the occiput comes directly into the posterior position (face to pubis) a vaginal delivery is possible if the pelvic diameters are reasonable.

Occipito-transverse position

The head engages in the left or right occipito-transverse position, but then rotation to occipito-anterior fails to occur and the head remains in the transverse position. If the second stage is reached the head must be manually rotated, rotated with appropriate forceps (namely, those with no pelvic curve—for example, Kielland’s forceps), or delivered using vacuum extraction.

Such vaginal deliveries must not be undertaken if there is any acidosis (fetal blood pH <7.15) as cerebral haemorrhage may result. They are now often undertaken in the operating theatre (trial of forceps) so that a rapid change to caesarean section can be made if there is any difficulty. Some obstetricians have abandoned these more difficult vaginal deliveries in favour of caesarean section.

Face and brow positions

If there is a complete extension of the fetal head, the face will present for delivery. Labour will be longer, but if the pelvis is adequate and the head rotates to a mentoanterior position, a vaginal delivery can be expected. If the head rotates backwards to a mentoposterior position a caesarean section is needed.

In a brow presentation the fetal head stays between full extension and full flexion so that the biggest diameter (the mento-vertex 13 cm) presents. This is usually only diagnosed once labour is well established. Unless the head flexes, a vaginal delivery is not possible, and a caesarean section is required.

Malpresentations

This is the commonest malpresentation. It is usually discovered before labour, although one third are not diagnosed until during labour, when vaginal examinations allow a more precise diagnosis to be made, especially as the cervix dilates and allows direct palpation of the presenting part of the fetus. Current opinion holds that in late pregnancy, external cephalic version should be offered, with the use of tocolytics in nulliparous women to relax the uterus. This procedure is successful in 40% of nulliparous women, and 60% of multiparous women if performed after 38 weeks. If breech presentation persists, preparations for delivery are made. Delivery should be in a hospital with an experienced midwife and obstetrician actively involved. An anaesthetist and paediatrician should be available.

All women with malpresentations and malpositions should be delivered in hospital

Vaginal delivery of breech presentation

• The mother should be in the lithotomy position (laterally tilted to avoid supine hypotension)
• The bladder should be emptied
• An anaesthetist and a paediatrician should be present
• An episiotomy is advisable
• The breech, legs, and abdomen should be allowed to deliver spontaneously (the legs can be assisted by flexing)
• The shoulders can be encouraged to deliver by rotation of the trunk (Lövsett’s manoeuvre)
• Delivery of the head should be controlled manually or with forceps

With a normal pelvis and the fetus’s weight estimated by ultrasonography to be 2500-4000 g, assisted breech delivery in experienced hands is probably as safe as a caesarean section. These days many women with a breech presentation choose to have a caesarean section as they think this is the safest method of delivery. In the past doctors have led them to believe this, but meta-analyses of randomised controlled trials do not substantiate this view. Of those women who aim for a vaginal delivery, about half will succeed. Before 32 weeks, caesarean section is commonly performed for a breech presentation, although the evidence of its effectiveness even at this gestation is not strong; the operation can be technically difficult, leading to maternal complications (see next article).

Breech delivery is an art that all those practising obstetrics need to learn, with supervision by senior practitioners, because unexpected breech deliveries still occur.

Transverse lie

When the fetus is lying sideways with the head in one flank and the buttocks in the other, it cannot be born vaginally. Unless it converts or is converted in late pregnancy, a caesarean section is required. After opening the abdominal wall, the surgeon may be able through the wall of the uterus to rotate the fetus so that it then becomes a longitudinal lie. If not, the uterine incision must be so placed transversely to allow access to a fetal pole.

Nowadays internal podalic version is not often attempted in transverse lies; a caesarean section is thought to be safer, although it can be a difficult operation

Prolapsed umbilical cord

If the presenting part of the fetus does not fit the pelvis after membrane rupture, the umbilical cord can slip past and present at the cervix, or actually prolapse into the vagina. If such an event is diagnosed in labour, the woman should be transferred straight to a hospital, preferably in a steep lateral or knee chest position with a midwife holding up the presenting part with fingers in the vagina, to stop it compressing the umbilical cord during contractions. A caesarean section is needed urgently.

If the cord is found ahead of the presenting part before membrane rupture, the membranes should be ruptured artificially only if full preparations for an emergency caesarean section have been made. The cord often slips to one side of the head and disappears when the membranes rupture.

Shoulder dystocia

After delivery of the head the hardest part of delivery is usually over, but occasionally the shoulders are slightly broader than usual, with a bisacromial diameter greater than 10 cm. The shoulders usually adopt the antero-posterior axis to negotiate the outlet. If the shoulders are still above the brim at this stage, no advance occurs. The baby’s chest is trapped within a vaginal cuirass. Although the nose and mouth are outside, the chest cannot expand with respiration. There is currently no way of predicting this problem reliably. The fifth annual report from the confidential inquiry into stillbirths and deaths in infancy (1998) considers the problem well.

Shoulder dystocia: best delivery method

• Flex and abduct the mother’s thighs as much as possible (the McRoberts procedure) and then depress the baby’s head towards the mother’s anus, with an assistant applying suprapubic pressure
• If this does not work, then manual rotation of the baby through 180° by vaginal and abdominal pressure may succeed
• Cleidotomy or symphysiotomy is the last resort and should be attempted only by an experienced obstetrician

Multiple pregnancies

Multiple pregnancies are increasing in frequency in Britain, mainly as a result of infertility treatment (both ovarian stimulation and in vitro fertilisation). Nearly all multiple pregnancies are now diagnosed early by ultrasound examination. Some twins, however, die and are absorbed in the first half of pregnancy (the disappearing twin syndrome). When pregnant with twins, most women go into labour early at about 37 weeks. The woman should be in labour in a hospital with a special care baby unit. With no complicating factors, the mother can go into spontaneous labour provided that the first twin is lying longitudinally. It is wise to have an intravenous line running. Labour usually proceeds rapidly; although each fetus is small, the total content of the uterus is large. The fetal heart rates of each twin should be monitored separately; some cardiotocographs allow this to be shown on a single chart. An anaesthetist should be present at delivery, and an epidural makes delivery of the second twin easier if there is a malpresentation (which occurs in 5-15% of cases). Paediatricians also should be present at the second stage of labour.

Multiple births in United Kingdom, 1995

Data supplied by Multiple Births Foundation.

*A maternity is any pregnancy that results in the birth of at least one live baby; the total number of maternities in 1995 was 725 638.

Conclusions

• Women with a fetus with an abnormal presentation or position should be transferred to hospital for the best care
• Problem cases should be anticipated
• Emergencies during an apparently normal labour need the immediate attention of a skilled obstetrician
• Prepared protocols ensure that all members of the labour ward team know their function and what should be done

Key references

• Johnstone F, Myerscough P. Shoulder dystocia. Br J Obstet Gynaecol 1998;105:811-5.
• Hofmeyr J. Planned elective caesarean section for term breech. In: Cochrane Collaboration. Cochrane Library . Issue 4. Oxford: Update Software, 1997.

After the first twin is delivered, the cord should be clamped and the lie of the second twin assessed carefully. This can be done clinically, but ultrasound scanning is more reliable. If the lie is not longitudinal, it should be made so by an external cephalic or internal podalic version. Unless uterine contractions return within 15 minutes, stimulation of the uterus with dilute oxytocin should be started, with an aim of delivering the second twin 25-45 minutes after the first. If there is any difficulty in delivery of the second twin, or if this twin develops a bradycardia, a vacuum extraction (in a cephalic presentation) or a breech extraction, if the fetus is lying the other way, can be performed. Internal podalic version and breech extraction is usually easy in this situation. It is not necessary to resort automatically to a caesarean section.

Fetal head engages in left occipito-anterior position (top) then descends into mid-cavity and rotates to full occipito-anterior (bottom)

If, instead of the normal curve, the sacrum is straightened (shaded area), the anterior-posterior diameter in mid-cavity is reduced (A-A), thus hindering head rotation in this zone

Three methods of delivering a baby in occipito-transverse position in the second stage of labour: (a) vacuum extraction with a linear pull, so allowing rotation to occur according to the pelvic anatomy; (b) rotation and extraction with Kielland’s (straight) forceps; or (c) manual rotation of head and then forceps applied immediately, once occipito-anterior position is achieved

Left: Abdominal features of a face presentation; the head is felt on the same side as the back and is often not engaged. Right: Abdominal features of a brow presentation—both the sinciput and the occiput are equally palpable on each side of the lower abdomen; the head is commonly not engaged

Transverse lie with subseptate uterus and low lying placenta

Prolapsed cord into the vagina after membrane rupture with a high head

Philip Steer is professor of obstetrics and consultant obstetrician at the Imperial College School of Medicine, Chelsea and Westminster Hospital, London.

The ABC of Labour Care is edited by Geoffrey Chamberlain, emeritus professor of obstetrics and gynaecology at the Singleton Hospital, Swansea. It will be published as a book in the summer.

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CHAPTER 22:  Normal Labor

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Fetal orientation.

• MECHANISMS OF LABOR
• NORMAL LABOR CHARACTERISTICS
• MANAGEMENT OF NORMAL LABOR
• LABOR MANAGEMENT PROTOCOLS
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Labor is the process that leads to childbirth. It begins with the onset of regular uterine contractions and ends with delivery of the newborn and expulsion of the placenta. Pregnancy and birth are physiological processes. Thus, labor and delivery should be considered normal for most women.

Fetal position within the birth canal is critical to labor progress and to the delivery route. It should be determined in early labor, and sonography can be implemented for unclear cases. Important relationships include fetal lie, presentation, attitude, and position.

Of these, fetal lie describes the relationship of the fetal long axis to that of the mother. In more than 99 percent of labors at term, the fetal lie is longitudinal . A transverse lie is less frequent. Occasionally, the fetal and maternal axes may cross at a 45-degree angle to form an oblique lie . This is unstable and becomes longitudinal or transverse during labor.

Fetal Presentation

The presenting part is the portion of the fetal body either within or in closest proximity to the birth canal. It usually can be felt through the cervix on vaginal examination. In longitudinal lies, the presenting part is either the fetal head or the breech, creating cephalic and breech presentations, respectively. When the fetus lies with the long axis transversely, the shoulder is considered the presenting part.

Cephalic presentations are subclassified according to the relationship between the head and body of the fetus ( Fig. 22-1 ). Ordinarily, the head is flexed sharply so that the chin contacts the thorax. The occipital fontanel is the presenting part, and this presentation is referred to as a vertex or occiput presentation . Much less often, the fetal neck may be sharply extended so that the occiput and back come into contact, and the face is foremost in the birth canal— face presentation . The fetal head may assume a position between these extremes. When the neck is only partly flexed, the anterior (large) fontanel may present— sinciput presentation . When the neck is only partially extended, the brow may emerge— brow presentation . These latter two are usually transient. As labor progresses, sinciput and brow presentations almost always convert into occiput or face presentations by neck flexion or extension, respectively. If not, dystocia can develop ( Chap. 23 , p. 441).

FIGURE 22-1

Longitudinal lie, cephalic presentation. Differences in attitude of the fetal body in (A) occiput, (B) sinciput, (C) brow, and (D) face presentations. Note changes in fetal attitude as the fetal head becomes less flexed.

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Internal podalic version for neglected shoulder presentation with fetal demise

Affiliation.

• 1 Department of Obstetrics and Gynaecology, Padhar Hospital, Padhar, Dist-Betul, Madhyapradesh, India. [email protected]
• PMID: 19656146
• DOI: 10.1111/j.1471-0528.2009.02296.x

In modern obstetrics, the role of internal podalic version (IPV) is limited to delivery of the second twin. A retrospective study was conducted to assess the efficacy of IPV in singleton neglected shoulder presentation with fetal demise. Women with live fetuses, previous CS or contracted pelvis were excluded. The procedure involved repositioning the prolapsed hand under anaesthetic followed by breech extraction. 12 women were identified over a 19 month period and all underwent successful IPV. One woman had a postpartum haemorrhage. We conclude that, in singleton pregnancies with a transverse lie, IPV has a role to play in the delivery of dead fetuses.

Publication types

• Evaluation Study
• Developing Countries
• Fetal Death / surgery*
• Labor Presentation*
• Obstetric Labor Complications / surgery*
• Retrospective Studies
• Version, Fetal / methods*

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Victoria’s Secret is bringing its controversial fashion show back to the runway

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The Angels are back.

While Victoria’s Secret tried a revamped version of its iconic fashion show in 2023, the brand announced Wednesday that it was bringing the catwalk spectacular back to its original format with a splashy runway show this year.

The new show “will deliver precisely what our customers have been asking for – the glamour, runway, fashion, fun, wings, entertainment – all through a powerful, modern lens reflecting who we are today,” a spokesperson for the brand tells Page Six Style.

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Victoria’s Secret tested a new format for its fashion show last year after receiving backlash for not including a diverse range of models in its annual TV special.

The show went on a four-year hiatus after facing  plummeting ratings  in 2018, returning with the “Victoria’s Secret World Tour” in 2023, which was a more fluid pre-taped presentation and streamed on Prime Video.

The brand’s fashion show debuted in 1997 and featured a range of big-name models — dubbed Victoria’s Secret Angels — over the years, with the likes of Heidi Klum, Gisele Bündchen, Naomi Campbell, Kendall Jenner, Claudia Schiffer and Tyra Banks walking the catwalk.

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Fans eagerly tuned in each year to see the steamy lingerie and performances from artists like Taylor Swift, Rihanna and the Spice Girls, but the special — which swapped between airing on ABC and CBS —  dipped in popularity in the wake of the #MeToo movement.

However, it seems like the company is going back to basics after the “World Tour” special featuring Doja Cat shook things up from the typical runway format.

Though there is no date announced, the brand tells us it’s “thrilled to share a women-led articulation of this iconic property later this year.”

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