PP

1. ABNORMAL LIE & PRESENTATION
Associate Professor Dr Hanifullah Khan

2. 2
Objectives
Understand fetal skull & pelvic anatomy
Basic definitions in obs
Identify types of abnormal lie and presentation
Identify causes of each abnormal lie and presentation
Making a diagnosis which includes history taking,
physical examination and investigation

3. Pelvis
• Space or compartment surrounded by the pelvic girdle
(bony pelvis)
• Subdivided into greater and lesser pelvis
– greater pelvis affords protection to inferior abdominal viscera
– lesser pelvis provides the skeletal framework for both the
pelvic cavity and the perineum

4. Normal pelvis - anatomy
• The bony pelvis is
formed by 4 bones:-
a. Right and left hip bones
(fusion of Ilium,
Ischium and Pubis)
b. Sacrum (fusion of 5
sacral vertebrae)
c. Coccyx
• Joints :-
– 2 Sacroilliac joints
– Pubic Symphysis and
– Sacrococcygeal joint
Clinically Oriented Anatomy, 5th
Edition, Moore, Keith L.; Dalley,
Arthur F. page 357

5. Pelvic inlet
• Bounded:
– anterior by Pubic
symphysis
– laterally by upper margin
of pubic bones, the
ileopectineal line & ala of
the sacrum
– Posteriorly by the sacral
promontory.
• Normal Transverse
diameter = 13.5 cm
• Anterior-Posterior
diameter = 11.0 cm

6. Inlet – side view
• The angle of the inlet:
– -normally 60° to the
horizontal in the erect
position.
– Increase in angle may
delay the head entering the
pelvis in labour

7. Pelvic mid cavity
• area bounded:
– anteriorly by middle of Symphysis
Pubis
– -laterally by pubic bones and
inner aspect of the ischial
spine and bone
– posteriorly by junction of 2nd
and 3rd sacral section.
• Cavity almost rounded.
Transverse &AP diameter are
similar at 12cm.
• The ischial spines are palpable
vaginally and used as landmarks
to assess the station and pudendal
anaesthetic block.

8. Pelvic outlet
• Bounded:
-anteriorly by the lower
margin of the of SP
-laterally by the
descending ramus of
the pubic bone, ischial
tuberosity and
sacrotuberous ligament
-posteriorly bounded to
last segment of sacrum

9. Pelvic outlet diameters
 Transverse diameter =
11 cm
 AP diameter = 13.5 cm

10. Types of pelves
• 4 common pelvic shapes in female
-Gynaecoid pelvis(most favourable for labour)
-Android pelvis(predispose to deep transverse arrest)
-Anthropoid pelvis (encourage occipito-posterior position)
-Platypelloid pelvis(increase risk of obstructed labour)

11. Pelvic shapes

12. Fetal skull
Made up of:
• Vault (formed by the
parietal bones, part of the
occipital, frontal and
temporal bones), Face
and Base.
• Sutures-sagittal, coronal,
frontal, temporal
• Fontanelles(anterior and
posterior)

13. Skull diameters
• The fetal head is ovoid
in shape.
• The attitude of the fetal
head refers to the
degree of the extension
or flexion at the upper
cervical spine.

14. Attitudes & diameters

15. Basic Definition
• Lie – Relationship between long axis of fetus and long
axis of uterus
• Presentation- Part of the fetus that presents to the
maternal pelvis

16. Types
Abnormal lie Abnormal presentation
Transverse Breech
Oblique Face
Unstable Brow
Shoulder

17. Abnormal lie

18. Abnormal
presentation

19. Causes & associations
Unknown
Cephalopelvic disproportion
Risk factors:
Preterm delivery
Small for dates
Fetal anomalies
Polyhydramnios
Multiparous /high parity
• Others
Placenta praevia
fetal thyroid
enlargement
Uterine & abd wall
laxity
Uterine abnormality
Abnormal fetal
position
19

20. BREECH PRESENTATION
Definition: Baby presents with the buttocks or feet rather
than the head first (cephalic presentation)
20

21. 21
Classification of Breech
Presentations

22. 22
Face Presentation
Face: presenting part is the face, denominator is mentum

23. Brow Presentation
Brow: when the portion
of the fetal skull just
above the orbital ridge
presents
Should be suspected in
unexpectedly prolonged
labour with failure to
progress
23

24. Transverse Lie

25. Shoulder
presentation

26. CLINICALDIAGNOSIS

27. Important
• Dates must always be determined
– By history
● Regularity of periods
● Dates of onset of pregnancy symptoms
● Date of quickening
– Examination
● Uterine size & fundal assesment
– Ix
● Ultrasound scanning (esp. 1st trimester)

28. Discrepancy in dates
• This can lead to a wrong diagnosis of abnormal lie
• Preterm fetuses are prone to abnormal lie
• Confirmation of dates can rule out macrosomia (a cause
of abn lie & presentation)

29. History taking
• Assess pregnancy for risk factors
• Previous or current history of vaginal bleeding includes
onset, duration, amount, character and aggravating factor (to
rule out placenta praevia)
• Ask for any history of decreased fetal movement
• Any previous or current history of multiple pregnancy

30. Past History
• Previous history of abnormal lie and presentation.
• Previous history of preterm delivery
• History of fetal anomalies (eg:hydrocephalus)
• History of tumour (thyroid, pelvis)

31. Physical examination
• Inspection (asymmetrical or fullness at certain areas of
abdomen)
• Palpation –
– measure the SF height (whether it corresponds to date)
– assess number of fetal poles
– grip palpation to assess fetal lie and presentation
– leopold maneuvers
– palpation of pelvic brim might reveal an empty pelvis
– assess adequacy of liqour
– Estimate fetal weight
• Vaginal examination- can be empty or other parts
besides fetal head.

32. Leopold’s maneuver

33. Investigations
• Ultrasound scan
- to rule out any fetal anomalies and assess amount of
liqour)
- to check for the presentation and lie of the fetus
• MOGTT – for gestational diabetes

34. Management
• Caesarean section is the form of delivery
• Well planned vaginal delivery may be attempted
– in cases of abnormal cephalic presentations e.g. face
• External cephalic version: maneuvering infant to a vertex
position (only if breech is diagnosed before onset of
labour).