Occipito posterior positition

DR. S.N. BERA & M. DASH
M.K.C.G MEDICAL COLLEGE ORISSA

 An abnormal position of the vertex rather than an
abnormal presentation.
 In a vertex presentation when occiput is placed
posteriorly over the sacro -illiac joint or directly over
sacrum, it is called occipito -posterior position.

 When the occiput is placed over right sacro-illiac
joint , Right occipito-posterior(ROP)/3RD position of
vertex.
 When the occiput is placed over left sacroilliac joint,
Left occipito -posterior(LOP).also called 4th position of
vertex.
 when it points towards sacrum, is called Direct
occipito-posterior .

INCIDENCE
 At the onset of labour ,the incidence of O-P is about
10% & is much less in late second stage of labour.
 ROP is 5 times more common than LOP
 Presence of sigmoid colon on the left & dextro-
rotation of the uterus favours ROP.

CAUSES
 MATERNAL-
shape of inlet- Anthropoid/android pelvis
more than 50% cases because the wide occiput can be
comfortably placed in wider posterior segment of pelvis.

 FETAL-Marked deflection of head favours posterior
position. It occurs due to
 High pelvic inclination.
 placenta previa
 pelvic tumours
 Primary brachycephaly
 UTERINE –Abnormal uterine contraction

Diagnosis: –
Inspection :-
- Abdomen looks flat below the umbilicus.
Palpation :-
Fundal height :- corresponds with period of
amenorrhoea.
Fundal grip :- breech.

Inspection- infra umbilical flattening

Lateral grip :-Foetal back is felt on rt. Flank of
mother 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.

-Auscultation :
FHS is best heard in flank in direct occipito –
posterior / R.O.P.
-but difficult in L.O.P.

Vaginal examination :-
1. Finding depends upon degree of flexion of head.
2. Confirmation made during 2nd stage of labour:-
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.

 Sometimes the position is not recognized until there is
delay in the second stage of labour.
 The diagnosis by vaginal examination may be difficult due
to the formation of caput succedaneum over the presenting
part.
 In this case the fingers may be passed higher to feel the free
margin of the ear which will point to the occiput.

MECHANISM OF LABOUR The head engages through right oblique diameter in
ROP & left oblique diameter in LOP.
 The engaging transverse diameter of head is biparietal
(9.5cm)
 Anterior-posterior diameter is either
suboccipitofrontal (1ocm) or occipitofrontal (11.5cm).

IN FAVOURABLE CASES(90%)
 Good uterine contraction results in good flexion of
head. normal descent occur up to pelvic floor.
 Occiput rotates 3/8th of a circle(135degree) anteriorly
to lie behind symphysis pubis. shoulders rotate about
2/8th of circle to occupy oblique diameter.
 Rest of the mechanism is like that of right
occipitoanterior in ROP & left occipitotanterior in
LOP.

UNFAVOURABLE CASES(10%)
non rotation or malrotation
 Certain cases occiput fails to rotate-
 Deflexion of the head
 Weak uterine contraction
 Flat sacrum
 Prominent ischial spine
 Convergent side walls
 Weak pelvic floor muscles
 Big baby
 Early drainage of liquor

 3 types results
 Incomplete forward rotation –occiput rotates 1/8th of
circle sagital suture comes to lie in bispinous diameter
results in Deep transverse arrest. It occurs in mild
deflexion of head.
 Nonrotation –both sinciput & occiput reaches pelvic
floor at same time & sagital suture lies in oblique
diameter results in Oblique posterior arrest. It occurs
inmoderate deflexion of head.

 Malrotation - the sinciput touches pelvic floor first
resulting in anterior rotation of sinciput 1/8th of circle
putting occiput to sacral hollow called Persistent
Occiput -posterior Position of vertex. It occurs in
extreme deflexion. Also called occipito -sacral
position.

 In favourable circumstances in persistent
occipitoposterior position, spontaneous delivery
occurs as face to pubis. Descend of head occurs until
root of nose hinges under symphysis pubis. Delivery
of brow, vertex, occiput lastly face is born by
extension .Restitution ,external rotation &delivery of
trunk occurs normally.

COURSE OF LABOUR
 Avg duration of both 1st& 2nd stage of labour is
increased.
 FIRST STAGE-
engagement is delayed
 persistence of deflexion of head
Driving force transmitted through the fetal axis is
not alignment with axis of inlet.

Early rupture of membrane occur.
Abnormal uterine contraction
SECOND STAGE-delayed due to long internal
rotation or malrotation , with at times, arrest of
head
THIRD STAGE-increased incidence of postpartum
hemorrhage & trauma to genital tract

MODE OF DELIVERY
Long anterior rotation of occiput -spontaneous or
assisted vaginal delivery occurs.(90%)
Short posterior rotation-spontaneous or assisted
vaginal delivery may occur as face to pubis. but there is
more chance of perineal tear

 Non-rotation or short anterior rotation-spontaneous
vaginal delivery highly unlikely . May progress to
prolonged or obstructed labour.

MANAGEMENT OF LABOUR
Early diagnosis
Strict vigilance with watchful expectancy hoping for
descent &anterior rotation of occiput
Judicious & timely interference if needed
Early caeserean section

Management of the first stage of labour:
The 1st stage is managed as in a normal case.
Nothing can be done to correct the Malposition or to
influence the rotation of the head at this stage.
A partogram is done to monitor the :
1.Uterine contraction (frequency, duration and strength
).
2.Fetal heart.
3.Dilatation of the cervix.

If progressive cervical dilatation does not occur
augmentation with an oxytocin drip may be tried.
If still no progress obtained in a few hours
caesarian section (C/S) is performed.
Also if there is fetal distress C/S is done

Management of the 2nd stage of labour:
1.In most cases (70% ) provided that the uterine contractions
are strong and the woman is able to make good expulsive
efforts the occiput rotates forward and normal delivery
takes place.
2.In other cases (10% ) the baby may be delivered face-to-
pubes with out difficulty but there is a great risk of a
perineal tear.

 3.In about 20% of cases there is failure of the
presenting part to rotate and descend and such
cases delivered by C/S or rotation can be enhanced
by assistance .

Arrest In occipito-transverse or
oblique position
Ventouse- It is suitable in cases where the pelvis is
adequete & non-rotation of the occiput due to
weak contraction or lack of tone of pelvic floor .

Fate of OPP
OPP
Engaging diameter :- occipito-
frontal 11.5cm or sub-occipitofrontal
10cm.
Favorable (90%)
Unfavorable (10%)
3/8th rotation
occiput comes under
symphysis pubis (rt/lt
occipito anterior)
Normal vaginal delivery
Mild deflexion
Moderate deflexion
Severe deflexion
Occiput rotate by
1/8th circle
Deep
transverse
arrest
Non-rotation
Oblique
posterior
arrest
Occiput rotate
posteriorly by 1/8th
POPP/ occipito-
sacral position
Face to pubis
delivery
Arrest

Alternative methods-
Manual rotation followed by forceps extraction
Forceps rotation & extraction
Caesarean section
craniotomy

Manual rotation & forcep
extraction
 First head is rotated manually till the occiput is
placed behind symphysis . It is done with either by
whole hand method or half hand method. Then
forceps blades are applied.
The pelvis should be adequate,
Baby is of average size
There is good amount of liquor

Manual rotation and forceps delivery:
Should be done under pudendal block or general
anaesthesia.
The head is rotated with the fingers to a direct
anterior position.

The shoulder girdle of the fetus should be rotated
at the same time as the head by pressure through
the abdominal wall by external hand.
After rotation completed an obstetric forceps are
applied to complete the delivery.

Difficulties are-
Failure to grip head adequately due to lack of space.
Failure to dislodge head from impacted position
Inadequate anaesthesia
Wrong case selection
Complications-
Accidental slippage of head
Prolapse of cord

Forceps rotation&extraction
It is done by experts
 Kielland’s forceps used.
Advantage over manual rotation
No chance of displacement of head
No accidental cord prolapse
Rotation can be done above or below the level of
obstruction

Caeserean section-if there is midpelvic contraction,I t
is much safer than rotation
Craniotomy- it is done in case of dead baby

Occipito sacral arrest
 Below the
spine
Station of head
Above the
level of ischial
spine
C/S
Ventouse or
forceps with
deep
episiotomy

Deep transverse arrest:
Means arrest of labour when the fetal head has descended
to the level of the ischial spines and the sagittal suture lies
in the transverse diameter of the pelvis.
The occiput lies on one side of the pelvis and the sinciput
on the other side and the head is badly flexed.

It is only diagnosed during the 2nd stage of labour.
If the head is firmly fixed in the transverse
position obstructed labour will occur

Management of DTA
DTA or oblique posterior arrest
Assisted delivery
Pelvis adequate Inadequate pelvis
-Manual rotation of occiput to
anterior position followed by forceps
extraction
- vacuum delivery
- forceps rotation
Dead baby
Craniotomy
C/S

Occipito posterior positition

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