MAL POSITIONS / MAL PRESENTATIONS

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MAL POSITIONS / MAL PRESENTATIONS

• Occiptio-posterior position 1 in 5
  deliveries
• Face presentation 1 in 500 deliveries
• Brow presentation 1 in 1000 deliveries
• Breech presentation 1-2 in 50 deliveries
• Shoulder presentation 1 in 200 deliveries
• Unstable lie 1 in 350 deliveries

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• Occipito posterior position..
• In a vertex presentation when the occiput is
  placed posteriorly over the sacrum / sacro
  iliac joint, it is called an occipito posterior
  position.

R.O.P. Occiput on right sacro - iliac
joint. L.O.P. Occiput on left sacro iliac
joint. Direct occipito posterior occiput
points towards sacrum.
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LOP
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• Occipito posterior is an abnormal position of
  the vertex rather than an abnormal presentation.
  (In most of cases (90) anterior rotation of
  occiput occurs.) But as the posterior position
  may give rise to Dystocia (abnormal labour
  delivery), it is associated with mal presentation.

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• Incidence upto 13 of all vertex presentation.
• R.O.P. is 3 times more common than L.O.P.
• WHY ??
• -Dextro-rotation of the uterus favours
  occipito-posterior than right occipito-anterior
  position
• -The right oblique diameter is slightly longer
  than the left one
• -The left oblique diameter is reduced by the
  presence of sigmoid colon

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• Causes -
• Not clear but factors abound
• CPD , Maternal kyphosis
• Contracted pelvis-50 or more occipito
  posterior position is associated with either an
  anthropoid or android pelvis due to narrow
  fore-pelvis.
• 2. Fetus deflection of fetal head favours
  posterior position of the vertex. Causes of
  deflection are
• High pelvic inclination.
• Placenta praevia, pelvic tumors.
• 3. Uterus abnormal uterine contraction.
• 4. Pendulous abdomen esp. in multipara.

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• Diagnosis
• Inspection -
• Abdomen looks flat below the umbilicus.
• Palpation -
• Fundal height - corresponds with period of
  amenorrhoea.
• Fundal grip - breech.
• Lateral grip -Foetal back is felt on rt. Flank
  of mother in in ROP in left flank in LOP.
• Fetal limbs are felt easily as knob like
  structure anteriorly.
• Pelvic grip -Head is not engaged.
• -Cephalic prominance (sinciput) is not felt so
  prominent as found in well flexed occipito
  anterior.
• -In direct occipito posterior the small
  sinciput is confused with breech.

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• -Auscultation -
• FHS is best heard in flank in direct occipito
  posterior / R.O.P. but difficult in L.O.P.
• Vaginal examination -
• Finding depends upon degree of flexion of head.
• Conformed dx. Is made during 2nd stage of labour
  on rupture of membrane by-
• a. Sagittal suture- occupies any of the
  oblique diameter of pelvis.
• b. posterior fontanelle -felt near the
  sacro-iliac joint.
• c. anterior fontanelle - felt near the
  ilio-pectineal eminence.

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• Mechanism of labour
• Head engages through the right oblique diameter
  in R.O.P. Left oblique diameter in L.O.P.
  Because of deflection engagement is delayed.
• In most of the cases (90)
• a. flexion due to good uterine
  contraction there is flexion of head.
• b. internal rotation of the head occiput
  rotates to 135 degrees anteriorly to lie behind
  the symphysis pubis, shoulder rotates to occupy
  right oblique diameter.
• 3. Further descent delivery of the head occurs
  like occipito anterior position.
• 4. Birth of shoulders trunk is the same as
  that of occipito anterior.

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Fate of OPP
OPP
Engaging diameter - occipito-frontal 11.5cm or
sub-occipitofrontal 10cm.
Unfavorable (10)
Favorable (90)
3/8th rotation
Moderate deflexion
Severe deflexion
Mild deflexion
occipit comes under symphysis pubis (rt/lt
occipito anterior)
Occiput rotate by 1/8th circle
Non-rotation
Occiput rotate posteriorly by 1/8th
Oblique posterior arrest
POPP/ occipito-sacral position
Deep transverse arrest
Normal vaginal delivery
Face to pubis delivery
Arrest
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• Factors favouring long anterior rotation
• (1) Well flexed head.     
• (2) Good uterine contractions.              
• (3) Roomy pelvis.
• (4) Good pelvic floor.     
• (5) No premature rupture of membranes.
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• Causes of failure of long anterior rotation
• (1) Deflexed head.                          
• (2) Uterine inertia.
• (3) Contracted pelvis rotation of the head
  cannot easily occur in android pelvis due to
  projection of the ischial spines and convergence
  of the side walls.            
• (4) Lax or rigid pelvic floor.
• (5) Premature rupture of membranes or its rupture
  early in labour.

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Management

• During 1st stage-
• Early diagnosis
• Fetal, maternal condition and pelvic assessment
  should be done.
• Prevent rupture of membrane by bed rest in lt.
  lateral position.
• Partograph to be strictly maintain.
• Early c/s in contracted pelvis.

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Second stage
p/v exam- To see level of presenting part,
degree of flexion, position, caput, moulding, cx.
2nd stage
Unfavorable (10)
Favorable (90)
Ant. 3/8th rotation
Moderate deflexion
Severe deflexion
Mild deflexion
occipit comes under symphysis pubis (rt/lt
occipito anterior)
Occiput ant. rotate by 1/8th circle
Non-rotation
Occiput rotate posteriorly by 1/8th
Oblique posterior arrest
Deep transverse arrest
POPP/ occipito-sacral position
Normal vaginal delivery
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Management of DTA
DTA or oblique posterior arrest
Assisted delivery
Dead baby
Inadequate pelvis
Pelvis adequate
-Manual rotation of occiput to anterior position
followed by forceps extraction - vacuum
delivery - forceps rotation
Craniotomy
C/S
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• Manual rotation and extraction by forceps
•  
• Under general anaesthesia the following steps are
  done
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• 1-Disimpaction the head is grasped bitemporally
  and pushed slightly upwards.
• 2-Flexion of the head.
• 3-Rotation of the occiput anteriorly by the right
  hand vaginally aided by,
• - Rotation of the anterior shoulder abdominally
  towards the middle line by the left hand or an
  assistant.
• 4-- Fix the head abdominally by an assistant,
  apply forceps and extract it

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POPP
POPP
Arrest
Spontaneous face to pubis delivery
Dead baby
Adequate pelvis
Inadequate pelvis
C/S
Head above the ischial spine / big baby
Head below the spines
Craniotomy
Forceps with deep episiotomy
Manual rotation forceps
C/S (best)
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• Prognosis
• Increased maternal morbidity due to pronlonged
  labour increased incidence of operative
  delivery.