Presentation

1. OTHER MALPRESENTATIONS
Dr Candia Emmanuel
Arua RRH
17-Apr-2023

2. • >95% of fetuses at term present with vertex (area
subtended by two parietal eminences, anterior, and
posterior fontanelle), (Collins et al., 2013)
• Non vertex presentations (including breech,
transverse lie, face, brow and compound
presentations) occur in less than 4% of fetuses at
term (Medscape, accessed on 30th-Apr-2019)

3. Face Presentation
• With this presentation, the head is hyperextended so that the occiput
is in contact with the fetal back, and the chin (mentum) is presenting
• The fetal face may present with the chin (mentum) anteriorly or
posteriorly, relative to the maternal symphysis pubis
• Although some mentum posterior presentations persist, most convert
spontaneously to anterior even in late labour (Duff, 1981)
• If not, the fetal brow (bregma) is pressed against the maternal
symphysis pubis
• This position precludes flexion of the fetal head necessary to negotiate
the birth canal
• Thus, a mentum posterior presentation is undeliverable except with a
very preterm foetus
• Face presentations rarely deliver as such vaginally
• Face presentation occurs in 1 of every 600-800 live births, averaging
about 0.2% of live births (Medscape, accessed on 30th-Apr-2019)
• Incidence of face presentation is between 1:600 and 1:1500 deliveries
(Collins et al., 2013)
• Among more than 70,000 singleton newborns delivered at Parkland
Hospital, approximately 1 in 2000 had a face presentation at delivery

5. Aetiology
• Causes of face presentations are numerous and include
conditions that favor extension or prevent head flexion
• Maternal
• 1. CPD-Extended positions develop more frequently when the
pelvis is contracted or the foetus is very large, in 10-40% of cases
of face presentation (Medscape, accessed on 30th-Apr-2019)
• This high incidence of pelvic contraction should be kept in mind
when considering management
• 2. High parity is a predisposing factor to face presentation
(Fuchs, 1985)
• In these cases, a pendulous abdomen permits the back of the
foetus to sag forward or laterally, often in the same direction in
which the occiput points
• This promotes extension of the cervical and thoracic spine

6. • Foetal
• Preterm infants, with their smaller head dimensions, can
engage before conversion to vertex position (Shaffer, 2006)
• Bashiri and associates (2008) reported that fetal
malformations and hydramnios were risk factors for face or
brow presentations
• Anencephalic foetuses naturally present by the face, 30% of
cases with face presentation (Medscape, accessed on 30th-
Apr-2019)
• In exceptional instances, marked enlargement of the neck or
coils of cord around the neck may cause extension
• Placental
• Bashiri and associates (2008) reported that fetal
malformations and hydramnios were risk factors for face or
brow presentations

7. Diagnosis
• Face presentation is diagnosed by vaginal examination
and palpation of facial features (Cunningham et al.,
2014 and Collins et al., 2013)
• The orbital ridges, nose, malar eminences, mentum,
gums, and mouth can be distinguished (Collins et al.,
2013)
• It is possible to mistake a breech for a face presentation
because the anus may be mistaken for the mouth and
the ischial tuberosities for the malar prominences
• The demonstration of the hyperextended head by
imaging with the facial bones at or below the pelvic
inlet is characteristic

8. Mechanism of labour

9. Mechanism of labour
• Face presentations rarely are observed above the pelvic inlet
• Instead, the brow generally presents early and is usually
converted to present the face after further extension of the head
during descent
• The mechanism of labour in these cases consists of the cardinal
movements of descent, internal rotation, and flexion, and the
accessory movements of extension and external rotation
• Descent is brought about by the same factors as in cephalic
presentations
• Extension results from the relation of the fetal body to the
deflected head, which is converted into a two-armed lever, the
longer arm of which extends from the occipital condyles to the
occiput
• When resistance is encountered, the occiput must be pushed
toward the back of the foetus while the chin descends

10. • The objective of internal rotation of the face is to bring the chin
under the symphysis pubis
• Only in this way can the neck traverse the posterior surface of
the symphysis pubis
• If the chin rotates directly posteriorly, the relatively short neck
cannot span the anterior surface of the sacrum, which measures
about 12 cm in length
• Moreover, the fetal brow (bregma) is pressed against the
maternal symphysis pubis
• This position precludes flexion necessary to negotiate the birth
canal
• Hence, birth of the head from a mentum posterior position is
impossible unless the shoulders enter the pelvis at the same
time, an event that is impossible except when the foetus is
extremely small or macerated
• Internal rotation results from the same factors as in vertex
presentations

11. • After anterior rotation and descent, the chin and mouth
appear at the vulva, the undersurface of the chin presses
against the symphysis, and the head is delivered by flexion
• The nose, eyes, brow (bregma), and occiput then appear in
succession over the anterior margin of the perineum
• After birth of the head, the occiput sags backward toward
the anus
• Next, the chin rotates externally to the side toward which it
was originally directed, and the shoulders are born as in
cephalic presentations
• Edema may sometimes significantly distort the face
• At the same time, the skull undergoes considerable molding,
manifested by an increase in length of the occipitomental
diameter of the head

12. Management 1
• It’s a high risk delivery
• Explain the diagnosis, management options and outcomes
to the mother
• Reassure the mother
• Take appropriate history: symptoms, risk factors,
complications, differential diagnosis
• Do complete physical examination from head to toe, rule
out contracted pelvis which reduces chances of vaginal
delivery even in the presence of mentoanterior position
• Perform appropriate investigations including: blood-
complete blood count (haemoglobin), grouping and cross
match and book two units of blood; imaging-gestational
age, size, rule out cord prolapse, and others

13. Management 2
• In the absence of a contracted pelvis, and with effective labour, successful vaginal delivery
usually will follow (Cunningham et al., 2014)
• 60% are mentoanterior (MA), (Medscape, accessed on 30th-Apr-2019) and head can flex to
allow vaginal delivery
• Expectant management should be considered with mentoposterior
(MP) as about 20–30% will rotate on reaching the pelvic floor
• Forceps delivery is possible with an MA position well below spines (Collins et al., 2013)
• Persistent MP face presentations (25-33%, (Medscape, accessed on 30th-Apr-2019), cannot
deliver vaginally as it would require the head to overextend (Collins et al., 2013)
• Attempts to convert a face presentation manually into a vertex presentation (Thom
maneuver),
• internal podalic version
• manual or forceps rotation of a persistently posterior chin to a mentum anterior position, and
• extraction are dangerous and should not be attempted as these can lead to complications of
cord prolapse and fetal cervical cord injury (Cunningham et al., 2014 and Collins et al., 2013)
• Fetal heart rate monitoring is probably better done with external devices to avoid damage to
the face and eyes (Cunningham et al., 2014 and Collins et al., 2013)
• If there is poor progress or failure to rotate, CS is indicated because face presentations among
term-size foetuses are more common when there is some degree of pelvic inlet contraction
(Cunningham et al., 2014 and Collins et al., 2013)
• Oxytocin=caution

14. Management 3
• Offer routine care
• Nutrition
• Hygiene including oral care
• Rest and sleep
• Exercise
• Opening of bowels and bladder
• Monitor vitals and foetal parameters closely

16. Brow Presentation
• The incidence varies from 1 in 500 deliveries to 1 in 1400
deliveries (Medscape, accessed on 30th-Apr-2019)
• Incidence ranges between 1:1000 and 1:3500 deliveries
• The head occupies a position midway between full flexion
(vertex) and full extension (face), (Medscape, accessed on 30th-
Apr-2019 and Collins et al., 2013)
• It is diagnosed when that portion of the fetal head between the
orbital ridge and the anterior fontanel presents at the pelvic inlet
• The fetal head thus occupies a position midway between full
flexion (occiput) and extension (face)
• It can revert to a face or vertex presentation, but if it persists
vaginal delivery is not usually possible (Collins et al., 2013)
• Except when the fetal head is small or the pelvis is unusually
large, engagement of the fetal head and subsequent delivery
cannot take place as long as the brow presentation persists

18. Aetiology and Diagnosis
• The causes of persistent brow presentation are the
same as those for face presentation
• A brow presentation is commonly unstable and often
converts to a face or an occiput presentation ((Collins
et al., 2013 and Cruikshank, 1973)
• The presentation may be recognized by abdominal
palpation when both the occiput and chin can be
palpated easily, but vaginal examination is usually
necessary
• The frontal sutures, large anterior fontanel, orbital
ridges, eyes, and root of the nose are felt on vaginal
examination, but neither the mouth nor the chin is
palpable

19. Mechanism of labour
• With a very small foetus and a large pelvis, labour is generally easy,
but with a larger foetus, it is usually difficult
• This is because engagement is impossible until there is marked
molding that shortens the occipitomental diameter or more
commonly, until there is either flexion to an occiput presentation or
extension to a face presentation
• The considerable molding essential for vaginal delivery of a persistent
brow characteristically deforms the head
• The caput succedaneum is over the forehead, and it may be so
extensive that identifcation of the brow by palpation is impossible
• In these instances, the forehead is prominent and squared, and the
occipitomental diameter is diminished
• In transient brow presentations, the prognosis depends on the
ultimate presentation
• If the brow persists, prognosis is poor for vaginal delivery unless the
foetus is small or the birth canal is large
• Principles of management are the same as those for a face
presentation

21. Transverse Lie
• In this position, the long axis of the foetus is approximately perpendicular to that of
the mother
• When the long axis forms an acute angle, an oblique lie results
• The latter is usually only transitory, because either a longitudinal or transverse lie
commonly results when labour supervenes
• For this reason, the oblique lie is called an unstable lie in Great Britain
• In a transverse lie, the shoulder is usually positioned over the pelvic inlet
• The head occupies one iliac fossa, and the breech the other
• This creates a shoulder presentation in which the side of the mother on which the
acromion rests determines the designation of the lie as right or left acromial
• And because in either position the back may be directed anteriorly or posteriorly,
superiorly or inferiorly, it is customary to distinguish varieties as dorsoanterior and
dorsoposterior
• Transverse and oblique lie occur in 1:300 pregnancies and result in a
shoulder, limb, or cord presentation (Collins et al., 2013)
• Transverse lie was found once in 322 singleton deliveries (0.3 percent) at both the
Mayo Clinic and the University of Iowa Hospital (Cruikshank, 1973; Johnson, 1964)
• This is remarkably similar to the incidence at Parkland Hospital of approximately 1 in
335 singleton foetuses

22. Etiology
• Some of the more common causes of transverse lie include:
• Maternal
• (1) contracted pelvis
• (2) abnormal uterine anatomy,
• (3) abdominal wall relaxation from high parity,
• Women with four or more deliveries have a tenfold incidence of transverse
lie compared with nulliparas
• A relaxed and pendulous abdomen allows the uterus to fall forward,
deflecting the long axis of the foetus away from the axis of the birth canal
and into an oblique or transverse position
• Foetal
• (4) preterm foetus,
• Placental
• (5) hydramnios, and
• (6) placenta praevia,
• Placenta previa and pelvic contraction act similarly
• A transverse or oblique lie occasionally develops in labour from an initial
longitudinal position

23. Diagnosis
• A transverse lie is usually recognized easily, often by inspection alone
• The maternal abdomen is unusually wide and the fundus is lower than
expected for the gestation and the uterine fundus extends to only slightly above the
umbilicus (Cunningham et al., 2014 and Collins et al., 2013)
• No fetal pole is detected in the fundus and pelvic inlet, and the ballottable head is
found in one iliac fossa and the breech in the other (Cunningham et al., 2014 and
Collins et al., 2013)
• The position of the back is readily identifiable
• When the back is anterior (Fig. 23-9, p. 469), a hard resistance plane extends across
the front of the abdomen
• When it is posterior, irregular nodulations representing fetal small parts are felt
through the abdominal wall
• On vaginal examination, the pelvis is empty, and in the early stages of labour, if the
side of the thorax can be reached, it may be recognized by the “gridiron” feel of the
ribs (Cunningham et al., 2014 and Collins et al., 2013)
• With further dilatation, the scapula and the clavicle are distinguished on opposite
sides of the thorax
• A limb or cord may prolapse through the cervix (Cunningham et al., 2014 and Collins
et al., 2013)
• The position of the axilla indicates the side of the mother toward which the shoulder
is directed

25. Mechanism of labour
• Spontaneous delivery of a fully developed newborn is impossible with a persistent
transverse lie
• After rupture of the membranes, if labour continues, the fetal shoulder is forced into
the pelvis, and the corresponding arm frequently prolapses
• After some descent, the shoulder is arrested by the margins of the pelvic inlet, with
the head in one iliac fossa and the breech in the other
• As labour continues, the shoulder is impacted firmly in the upper part of the pelvis
• The uterus then contracts vigorously in an unsuccessful attempt to overcome the
obstacle
• With time, a retraction ring rises increasingly higher and becomes more marked.
With this neglected transverse lie, the uterus will eventually rupture
• Even without this complication, morbidity is increased because of the frequent
association with placenta previa, the increased likelihood of cord prolapse, and the
necessity for major operative efforts
• If the foetus is small—usually < 800 g—and the pelvis is large, spontaneous delivery
is possible despite persistence of the abnormal lie
• The foetus is compressed with the head forced against its abdomen
• A portion of the thoracic wall below the shoulder thus becomes the most dependent
part, appearing at the vulva
• The head and thorax then pass through the pelvic cavity at the same time
• The foetus, which is doubled upon itself and thus sometimes referred to as
conduplicato corpore, is expelled

26. Management
• Active labour in a woman with a transverse lie is usually an
indication for cesarean delivery
• Before labour or early in labour, with the membranes intact,
attempts at external version are worthwhile in the absence of
other complications
• If the fetal head can be maneuvered by abdominal manipulation
into the pelvis, it should be held there during the next several
contractions in an attempt to fix the head in the pelvis
• With cesarean delivery, because neither the feet nor the head of
the foetus occupies the lower uterine segment, a low transverse
incision into the uterus may lead to difficult fetal extraction
• This is especially true of dorsoanterior presentations
• Therefore, a vertical incision is typically indicated or TLSI after
acute tocolysis (Cunningham et al., 2014 and Collins et al., 2013)

28. Compound Presentation
• Incidence and Aetiology
• In a compound presentation, an extremity prolapses
alongside the presenting part, and both present
simultaneously in the pelvis
• Goplerud and Eastman (1953) identifed a hand or arm
prolapsed alongside the head once in every 700 deliveries
• Much less common was prolapse of one or both lower
extremities alongside a cephalic presentation or a hand
alongside a breech
• At Parkland Hospital, compound presentations were
identifed in only 68 of more than 70,000 singleton
foetuses—an incidence of approximately 1 in 1000
• Causes of compound presentations are conditions that
prevent complete occlusion of the pelvic inlet by the fetal
head, including preterm labour

31. Management and Prognosis
• In most cases, the prolapsed part should be left alone, because
most often it will not interfere with labour
• If the arm is prolapsed alongside the head, the condition should
be observed closely to ascertain whether the arm retracts out of
the way with descent of the presenting part
• If it fails to retract and if it appears to prevent descent of the
head, the prolapsed arm should be pushed gently upward and
the head simultaneously downward by fundal pressure
• Tebes and coworkers (1999) described a tragic outcome in a
newborn delivered spontaneously with the hand alongside the
head
• The infant developed ischemic necrosis of the presenting
forearm, which required amputation
• In general, rates of perinatal mortality and morbidity are
increased as a result of concomitant preterm delivery, prolapsed
cord, and traumatic obstetrical procedures

33. References
• Collins Sally, Arulkumaran Sabaratnam, Hayes Kevin,
Jackson Simon and Impey Lawrence (Eds) (2013).
Oxford Hand Book of Obstetrics and Gynaecology.
Oxford. Oxford University Press. Pp 315-319
• Cunningham F. Gary, Leveno J. Kenneth, Bloom L.
Steven, Spong Y. Catherine, Dashe S. Jodi, Hoffman L.
Barbara, Casey M. Brian and Sheffield S. Jeanne (Eds)
(2014). Williams Obstetrics. New York. McGraw-Hill
Education. 24th Edition. Pp 466-470
• (Medscape, accessed on 30th-Apr-2019)