MALPOSITIONS AND

MALPRESENTATIONS –

OCCIPITOPOSTERIOR, FACE, BROW,

SHOULDER

OCCIPITO-POSTERIOR

•Vertex presentation•Occiput in post. Segment of pelvis overlying the sacroiliac jt and sacrum• 3 positions described:1. Right occipitoposterior2. Left occipitopoterior3. Direct occipitoposterior

AETIOLOGY SHAPE OF PELVIC INLET- anthropoid or

android pelvis

FETAL FACTORS- marked deflexion- 1) high pelvic inclination 2) placenta on ant. Wall of uterus 3) back on the right side

UTERINE FACTORS- abnormal uterine contractions

DIAGNOSIS ABDOMINAL EXAMINATION Subumbilical flattening Back is in one or the other flank so clinically

not felt Limbs felt anteriorly Shoulder in flanks Unengaged or high head at term Occiput and sinciput at same level Fetal heart sounds in the flanks and are

frequently indistinct

VAGINAL EXAMINATION

Early In Labour-

Early rupture of membranes Sagittal suture in right oblique diameter Post. Fontanelle in right posterior quadrant

and ant. Fontanellae in left anterior quadrant Both fontanelle easily palpated

Late In Labour

Large caput present obscuring the sutures Pinna points occiput Perineum gapes much before head distends it

and premature straining can occur Difficulty in applying forceps in unrecognized

occipitoposterior

MECHANISM OF LABOUR ENGANGING DIAMETER Suboccipitofrontal-10.5cm Occipitofrontal-11.5cm

COURSE OF LABOUR

Anterior rotation- 90% cases, occiput rotates anteriorly through 3/8 of circle and baby born occipitoanterior.

Engagement may be delayed and labour may be longer because of deflexion.

Posterior Rotation And Face To Pubis Delivery Head is deflexed. Engaging diameter is occipitofrontal. Sinciput rotates anteriorly then occiput rotates

posterioirly Extreme flexion followed by extreme extension Perineal tears common Liberal episiotomy needed Occipitosacral position and face to pelvis are

more common anthropoid pelvis

Failure Of Rotation

Persistent occipitoposterior is the absence of rotation and head remains as ROP or LOP

Deep transverse arrest is defined as head being arrested with sagittal suture in transverse diameter at the level of ischial spine, after full dilation of cervix and inspite of good uterine contractions

Reasons-

Deflexion of the head Inefficient uterine contraction Weak pelvic floor preventing anterior rotation Pendulous abdomen and poor muscle tone Cephalopelvic disproportion and android

pelvis

MANAGEMENT

Most of the malpositions will rotate anteriorly and the baby will be born spontaneously as occiput anterior

Posterior rotation- labour longer- Judicious use of fluids, liberal

episiotomy and analgesia needed-partogram essential

- -oxytocin augmentation

DEEP TRANSVERSE ARREST

1. Caesarean section-android pelvis, cephalopelvic disproportions, traumatic vaginal delivery causing intracranial haemorrhage

2. Vacuum extraction- ideal- cup at posterior fontanelle- promotes flexion, thus decreases presenting diameter- promotes autorotation suited for the pelvis- less traumatic, no need for analgesia

3. Manual rotation- under GA

-right hand grasps the sinciput, displacing it and there by increasing flexion

- Small bitemporal diameter allows more space for the thumb and finger to have firm grasp across the temple with middle finger on the frontal suture

- In LOP, left hand used- sinciput rotated and forceps or vacuum used

4. Forceps Rotation-- Keilland forceps used- Under GA- In anteroposterior direction and rotation

carried out- Adv- forceps need not be reapplied

PERSISTENT OCCIPITOPOSTERIOR Oxytocin augmentation tried Most cases delivery as occipitoposterior

with face to pelvis, assisted with forceps or vacuum

Rotation to occipitoanterior can be attempted

Caesarean section otherwise

If any of the attempt to deliver the baby vaginally fails.. Immediate CS should be done

Otherwise, fetus may die and craniotomy by experienced hands or CS must be done

FACE PRESENTATION Cephalic presentation where the attitude is

one of complete extension, presenting part is face and denominator is the chin or mentum

Engaging diameter is submentobregmatic-9.4cm

Primary face presentation are present before onset of labour and are rare

Secondary caused by extension during labour and is most common

POSITIONS

Left mentoanterior(LMA) Right mentoanterior(RMA) Right mentoposterior(RMP) Left mentoposterior(LMP) 70% are mentoanterior and 30% posterior.

INCIDENCE AND AETIOLOGY Incidence- 1 in 500

Maternal Causes

- contracted pelvis

- obliquity of uterus

- multiparity or pendulous abdomen

Fetal Factors

-anencephaly and iniencephaly

-cord around the neck

-tumours of neck like congenital goitre

-spasm of sternocleidomatoid muscle

-dolicocephalic head

DIAGNOSIS ABDOMINAL EXAMINATION In mentoanterior, back is felt with difficulty as it

is posterior and limbs anteriorly Head remains high Cephalic prominence is the occiput and on the

same side as the back Groove b/w the head and back is prominent Fetal heart sounds are transmitted through the

chest and heard well anteriorly in mentoanterior

VAGINAL EXAMINATION

-conical bag of membranes

- chin, mouth, nose, malar eminences and supraorbital ridges are felt

-in mentoanterior, chin is in one ant. Quadrant and forehead in opp post. Quadrant

-done gently and without cream to avoid injury to eyes

MECHANISM OF LABOUR MENTOANTERIOR POSITION

1. Engagement

-engaging diameter- submentobregmatic-9.4cm

-biparietal diameter-7cm

This diameter pass only when face low down in perineum

-when face distending the vulva, head engaged

2. DESCENT WITH INCREASING EXTENSION

-Resistance encountered by extension

-occiput pushed towards back of fetus, while chin descends

3. INTERNAL ROTATION

-Rotates anteriorly through 45°towards symphysis

Neck traverse the posterior surface of symphysis pubis

4. FLEXION

-head born by flexion

-chin pivots under symphysis pubis and the mouth, nose, orbit, forehead ,vertex and occiput are born by flexion

5. RESTITUTION AND EXTERNAL ROTATION

-of chin occurs towards the side to which it was originally directed and the shoulder are born as in vertex

MENTOPOSTERIOR

-2/3RD cases rotate anteriorly through 3/8th circle and deliver as mentoanterior

-some in oblique diameter and some rotate posteriorly into the hollow of sacrum

-neck too short to span in the 12cm of the ant. Aspect of sacrum

-shoulders get impacted along with head making delivery impossible

-engaging diameter is sternobregmatic-17cm

-no mechanism of labour

CAUSES OF PROLONGED LABOUR

Face is less effective dilator of cervix No moulding of face More chance of rupture of membranes Long internal rotation in mentoposterior Internal rotation occurs only late in 2nd stage

COMPLICATIONS

MATERNAL

Prolonged labour Increased risk of operative delivery Obstructed labour in persistent

mentoposterior

FETAL

Face after delivery is oedematous Laryngeal oedema can also occur- baby

watched for 24 hrs Congenital malformations like anencephaly Birth asphyxia due to cord prolapse and

prolonged labour

MANAGEMENT

Mentoanterior, forward rotation in mentoposterior- labour allowed

CPD, anencephaly, other anomalies, persistent mentoposterior, obstructed labour- CS DONE

Dead baby- CS or craniotomy

BROW PRESENTATION

Most unfavourable Attitude is one of partial extension,

presenting part being the area between the ant. Fontanelle above and glabella and orbital ridges below and denominator is forehead or frontum

Presenting diameter is verticomental- 13.5cm

Transitory presentation- flex or extend

INCIDENCE AND AETIOLOGY INCIDENCE-1 in 1000 CAUSE- similar to face presentation and

include any factors that interfers with flexion of head

DIAGNOSIS

Rarely made before labour

ABDOMINAL EXAMINATION High mobile head, which feels large from

side to side Cephalic prominence is the occiput and is on

same side as back and groove between cephalic prominence and back is less prominent than in face presentation

VAGINAL EXAMINATION

Membranes felt in early labour Anterior frontanelle is felt at one end and root

of nose and orbital ridges at other end of oblique or transverse diameter

Nose and mouth are palpable but not the chin

MECHANISM OF LABOUR

Presenting diameter - verticomental No mech of labour for persistent brow

presentation Spontaneous labour only if baby very

small or pelvis large In persistent brow, verticomental dia is

shortened & the occipitofrontal dia elongated with marked moulding and large caput on forehead

COMPLICATIONS

Both maternal and fetal risks are more

MATERNAL

Obstructed labour and rupture uterus

FETAL

Birth asphyxia

MANAGEMENT ANTEPARTUM Wait till labour

EARLY LABOUR If membrane not ruptured wait for correction After membrane rupture, brow presentation

diagnosed and in persistent brow presentation –CS done

Prologed labour with head high.. Brow presentation must be suspected

LATE LABOUR If features of obstructed labour or if fetus

dead- immediate CS done If baby dead- also craniotomy

SHOULDER PRESENTATION AND TRANSVERE LIE

Long axes of fetal and maternal ovoid are approximately at right angles to each other and shoulder is presenting in the pelvic inlet.

Denominator- acromion

POSITIONS Right acromial Left acromial

DEPENDING UPON DIRECTION OF THE BACK

Dorsoanterior Dorsoposterior Dorsosuperior Dorsoinferior

INCIDENCE AND AETIOLOGY Incidence- 1 in 500 MATERNAL FACTOR Multiparity Contracted pelvis Uterine anomalies like septate,bicornuate

and arcuate uterus Placenta praevia Fibroid in the lower segment

FETAL FACTORS

Prematurity Multiple pregnancy Polyhydraminos IUD

DIAGNOSIS ABDOMINAL EXAMINATION Transversely stretched Fundal height less than period of gestation No Fetal pole at fundus Ballotable head in one flank & breech in the

other In dorsoanterior, back is felt a uniform

reistance acros the front of abdomen In dorsoposterior, limbs are felt anteriorly Empty pelvic grip

VAGINAL EXAMINATION

Conical bag of membranes with a high presenting part

Hand/shoulder/elbow may be felt as a uniform resistance across the front of abdomen

Shoulder can be identified by ribs running parallel to each other

Late in labour, shoulder may be wedged in the pelvis and hand freequently prolapse into the vagina

Thumb of the prolapsed hand, when supinated points to head

To side, to which the prolapsed hand belongs, can be determined by shaking hand with the fetus. If the right hand is required, prolapsed hand is the right and viceversa

ULTRASONOGRAPHY Confirms diagnosis and position Rules out anomalies Rules out placenta praevia

MECHANISM OF LABOUR

NO mechanism of labour Spontaneous version to breech or by

spontaneous rectification to vertex can occur Rarely if fetus small or dead delivery occurs

by:- Spontaneous expulsion or birth corpora

conduplicata where fetus is expelled doubled up

- Spontaneous evolution where breech and trunk are expelled followed by head

NEGLECTED SHOULDER PRESENTATION Due to ill fitting presenting part, membranes

may rupture early and freequently ensues cord prolapse, once labour commence

A labour pain becomes stronger, the shoulder forced into the pelvic inlet

Nullipara- uterine inertia Multipara-bandl ring or pathological retraction

ring-obstructed labour- neglected shoulder presentation

Mother-exhausted,febrile and urine show ketone bodies-uterine rupture- death of both mother and baby

COMPLICATIONS

MATERNAL Increased chance of caesarean section Obstructed labour or ruptured uterus

FETAL Birth asphyxia due to cord prolapse and

in obstructed labour

MANAGEMENT

EXTERNAL CEPHALIC VERION At term or early in labour if membranes

intact and not contraindicated More successful in multipara If successful followed by stabilizing

induction More success than for breech

CAESAREAN SECTION Best option When ECV fails and CI Transverse inscision

NEGLECTED SHOULDER PRESENTATION If baby dead-CS or craniotomy

Reference

Shiela B, Text book of Obstetrics.