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MALPOSITIONS AND MALPRESENTATIONS OCCIPITOPOSTERIOR, FACE, brow, shoulderOCCIPITO-POSTERIORVertex presentationOcciput in post. Segment of pelvis overlying the sacroiliac jt and sacrum 3 positions described:Right occipitoposteriorLeft occipitopoteriorDirect occipitoposteriorAETIOLOGYSHAPE OF PELVIC INLET- anthropoid or android pelvis

FETAL FACTORS- marked deflexion-1) high pelvic inclination 2) placenta on ant. Wall of uterus3) back on the right side

UTERINE FACTORS- abnormal uterine contractionsDIAGNOSISABDOMINAL EXAMINATIONSubumbilical flattening Back is in one or the other flank so clinically not feltLimbs felt anteriorlyShoulder in flanksUnengaged or high head at termOcciput and sinciput at same levelFetal heart sounds in the flanks and are frequently indistinct

VAGINAL EXAMINATION

Early In Labour-

Early rupture of membranesSagittal suture in right oblique diameterPost. Fontanelle in right posterior quadrant and ant. Fontanellae in left anterior quadrantBoth fontanelle easily palpatedLate In Labour

Large caput present obscuring the suturesPinna points occiputPerineum gapes much before head distends it and premature straining can occurDifficulty in applying forceps in unrecognized occipitoposteriorMECHANISM OF LABOURENGANGING DIAMETERSuboccipitofrontal-10.5cmOccipitofrontal-11.5cm

COURSE OF LABOURAnterior 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 DeliveryHead is deflexed.Engaging diameter is occipitofrontal.Sinciput rotates anteriorly then occiput rotates posterioirlyExtreme flexion followed by extreme extensionPerineal tears commonLiberal episiotomy neededOccipitosacral position and face to pelvis are more common anthropoid pelvisFailure Of Rotation

Persistent occipitoposterior is the absence of rotation and head remains as ROP or LOPDeep 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 headInefficient uterine contractionWeak pelvic floor preventing anterior rotationPendulous abdomen and poor muscle toneCephalopelvic disproportion and android pelvisMANAGEMENTMost of the malpositions will rotate anteriorly and the baby will be born spontaneously as occiput anteriorPosterior rotation- labour longerJudicious use of fluids, liberal episiotomy and analgesia needed-partogram essential-oxytocin augmentationDEEP TRANSVERSE ARREST

Caesarean section-android pelvis, cephalopelvic disproportions, traumatic vaginal delivery causing intracranial haemorrhageVacuum 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 flexionSmall bitemporal diameter allows more space for the thumb and finger to have firm grasp across the temple with middle finger on the frontal sutureIn LOP, left hand used- sinciput rotated and forceps or vacuum used4. Forceps Rotation-Keilland forceps usedUnder GAIn anteroposterior direction and rotation carried outAdv- forceps need not be reappliedPERSISTENT OCCIPITOPOSTERIOROxytocin augmentation triedMost cases delivery as occipitoposterior with face to pelvis, assisted with forceps or vacuumRotation to occipitoanterior can be attemptedCaesarean section otherwiseIf any of the attempt to deliver the baby vaginally fails.. Immediate CS should be doneOtherwise, fetus may die and craniotomy by experienced hands or CS must be doneFACE PRESENTATIONCephalic presentation where the attitude is one of complete extension, presenting part is face and denominator is the chin or mentumEngaging diameter is submentobregmatic-9.4cmPrimary face presentation are present before onset of labour and are rareSecondary caused by extension during labour and is most commonPOSITIONS

Left mentoanterior(LMA)Right mentoanterior(RMA)Right mentoposterior(RMP)Left mentoposterior(LMP)70% are mentoanterior and 30% posterior.INCIDENCE AND AETIOLOGYIncidence- 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 headDIAGNOSISABDOMINAL EXAMINATIONIn mentoanterior, back is felt with difficulty as it is posterior and limbs anteriorlyHead remains highCephalic prominence is the occiput and on the same side as the backGroove b/w the head and back is prominentFetal 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 LABOURMENTOANTERIOR POSITIONEngagement-engaging diameter- submentobregmatic-9.4cm-biparietal diameter-7cmThis 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 descends3. INTERNAL ROTATION-Rotates anteriorly through 45towards symphysisNeck traverse the posterior surface of symphysis pubis4. 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 vertexMENTOPOSTERIOR

-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 cervixNo moulding of faceMore chance of rupture of membranesLong internal rotation in mentoposteriorInternal rotation occurs only late in 2nd stageCOMPLICATIONSMATERNAL

Prolonged labourIncreased risk of operative deliveryObstructed labour in persistent mentoposteriorFETAL

Face after delivery is oedematousLaryngeal oedema can also occur- baby watched for 24 hrsCongenital malformations like anencephalyBirth asphyxia due to cord prolapse and prolonged labourMANAGEMENTMentoanterior, forward rotation in mentoposterior- labour allowedCPD, anencephaly, other anomalies, persistent mentoposterior, obstructed labour- CS DONEDead baby- CS or craniotomyBROW PRESENTATIONMost unfavourableAttitude 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 frontumPresenting diameter is verticomental- 13.5cmTransitory presentation- flex or extendINCIDENCE AND AETIOLOGYINCIDENCE-1 in 1000CAUSE- similar to face presentation and include any factors that interfers with flexion of headDIAGNOSISRarely made before labour ABDOMINAL EXAMINATIONHigh mobile head, which feels large from side to sideCephalic prominence is the occiput and is on same side as back and groove between cephalic prominence and back is less prominent than in face presentationVAGINAL EXAMINATION

Membranes felt in early labourAnterior frontanelle is felt at one end and root of nose and orbital ridges at other end of oblique or transverse diameterNose and mouth are palpable but not the chinMECHANISM OF LABOURPresenting diameter - verticomentalNo mech of labour for persistent brow presentationSpontaneous labour only if baby very small or pelvis largeIn persistent brow, verticomental dia is shortened & the occipitofrontal dia elongated with marked moulding and large caput on foreheadCOMPLICATIONSBoth maternal and fetal risks are moreMATERNALObstructed labour and rupture uterusFETALBirth asphyxia

MANAGEMENTANTEPARTUMWait till labour

EARLY LABOURIf membrane not ruptured wait for correctionAfter membrane rupture, brow presentation diagnosed and in persistent brow presentation CS doneProloged labour with head high.. Brow presentation must be suspected

LATE LABOURIf features of obstructed labour or if fetus dead- immediate CS doneIf baby dead- also craniotomySHOULDER PRESENTATION AND TRANSVERE LIELong axes of fetal and maternal ovoid are approximately at right angles to each other and shoulder is presenting in the pelvic inlet.Denominator- acromion

POSITIONSRight acromialLeft acromial

DEPENDING UPON DIRECTION OF THE BACK

DorsoanteriorDorsoposteriorDorsosuperiorDorsoinferior

INCIDENCE AND AETIOLOGYIncidence- 1 in 500MATERNAL FACTORMultiparityContracted pelvisUterine anomalies like septate,bicornuate and arcuate uterusPlacenta praeviaFibroid in the lower segmentFETAL FACTORS

PrematurityMultiple pregnancyPolyhydraminosIUDDIAGNOSISABDOMINAL EXAMINATIONTransversely stretchedFundal height less than period of gestationNo Fetal pole at fundusBallotable head in one flank & breech in the otherIn dorsoanterior, back is felt a uniform reistance acros the front of abdomenIn dorsoposterior, limbs are felt anteriorlyEmpty pelvic grip

VAGINAL EXAMINATION

Conical bag of membranes with a high presenting partHand/shoulder/elbow may be felt as a uniform resistance across the front of abdomenShoulder can be identified by ribs running parallel to each otherLate 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 headTo 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

ULTRASONOGRAPHYConfirms diagnosis and positionRules out anomaliesRules out placenta praevia

MECHANISM OF LABOURNO mechanism of labourSpontaneous version to breech or by spontaneous rectification to vertex can occurRarely if fetus small or dead delivery occurs by:Spontaneous expulsion or birth corpora conduplicata where fetus is expelled doubled upSpontaneous evolution where breech and trunk are expelled followed by head

NEGLECTED SHOULDER PRESENTATIONDue to ill fitting presenting part, membranes may rupture early and freequently ensues cord prolapse, once labour commenceA labour pain becomes stronger, the shoulder forced into the pelvic inletNullipara- uterine inertiaMultipara-bandl ring or pathological retraction ring-obstructed labour- neglected shoulder presentationMother-exhausted,febrile and urine show ketone bodies-uterine rupture- death of both mother and babyCOMPLICATIONSMATERNALIncreased chance of caesarean sectionObstructed labour or ruptured uterus

FETALBirth asphyxia due to cord prolapse and in obstructed labourMANAGEMENTEXTERNAL CEPHALIC VERIONAt term or early in labour if membranes intact and not contraindicatedMore successful in multiparaIf successful followed by stabilizing inductionMore success than for breechCAESAREAN SECTIONBest optionWhen ECV fails and CITransverse inscision

NEGLECTED SHOULDER PRESENTATIONIf baby dead-CS or craniotomyReferenceShiela B, Text book of Obstetrics.