Occipito posterior position

Shoulder Presentation (Transverse or Oblique lie)

Definition

When The fetus lies with its long axis across the long axis of the uterus, the shoulder is most likely to present,it is called transverse lie.

The longitudinal axis of the foetus does not coincide with that of the mother.

These are the most hazardous malpresentations due to mechanical difficulties that occur during labour .

The oblique lie which is deviation of the head or the breech to one iliac fossa, is less hazardous as correction to a longitudinal lie is more feasible.

Incidence

3-4% during the last quarter of pregnancy but 0.5% by the time labour commences. Or shoulder presentation occurs in approximately1:300 pregnancies near term. It is common in premature and macerated fetuses, 5 times more common in multiparae than primigravidae. Transverse lie in twins pregnancy is found in 40% of cases.Aetiology change the shape of pelvis, uterus or foetus,

Allow free mobility of the foetus as in case of prematurity, grandmultiparity and hydramnios. When the fetus is dead or macerated fetus due to lack of muscle tone causes the fetus to slump down in to the lower pole of the uterus has no muscle tone.

interfere with engagement as:

Maternal:

Contracted pelvis.

Lax abdominal wall.

Uterine causes as bicornuate, subseptate and fibroid uterus.

Pelvic masses as ovarian tumours.

Placenta previa: This may prevent head from entering the pelvic brim.

Foetal causes:

Multiple pregnancies.

Polyhydramnios.

Placenta praevia.

Prematurity.

Positions

The scapula is the denominator

Left scapulo-anterior.

Right scapulo-anterior.

Right scapulo-posterior.

Left scapulo-posterior.

Scapulo-anterior are more common than scapulo-posterior as the concavity of the front of the foetus tends to fit with the convexity of the maternal spines.

DiagnosisDuring pregnancy

Inspection:

The abdomen is broader from side to side.

Palpation:

Fundal level: lower than that corresponds to the period of amenorrhoea.

Fundal grip: The fundus feels empty.

Umbilical grip: The head is felt on one side while the breech one the other.

First pelvic grip: Empty lower uterine segment.

Auscultation:

FHS are best heard on one side of the umbilicus towards the foetal head.

Ultrasound or X-ray:

Confirms the diagnosis and may identify the cause as multiple pregnancy or placenta praevia.

During labour

In addition to the previous findings, vaginal examination reveals:

The presenting part is high.

Membranes are bulging.

Premature rupture of membranes with prolapsed arm or cord is common. When the cervix is sufficiently dilated particularly after rupture of the membranes, the scapula, acromion, clavicle, ribs and axilla can be felt, but not always. An arm may prolapse .Mechanism of Labour

As a rule no mechanism of labour should be anticipated in transverse lie and labour is obstructed.

If a patient is allowed to progress in labour with a neglected or unrecognized transverse lie, one of the following may occur:

Impaction: The shoulder is pushed into the pelvis and if the mother is not assisted, it may get impacted in the pelvis. This is the usual and most common outcome.

The lower uterine segment thins and ultimately ruptures.

The foetus becomes hyperflexed, placental circulation is impaired, and cord is prolapsed and compressed leading to foetal asphyxia and death.

Spontaneous rectification:

Rarely the foetal lie may be corrected by the splinting effect of the contracted uterine muscles so that the head presents.

Spontaneous version:

Rarely, the lie becomes longitudinalspontaneously, with either the breech or the head presenting. This usually occurs before the rupture of the membranes. Labour than progresses as for a longitudinal lie.

Spontaneous expulsion:

Very rarely, if the foetus is very small or dead and macerated, the shoulder may be forced through the pelvis followed by the head and trunk.

Spontaneous evolution:

Very rarely, the head is retained above the pelvic brim, the neck greatly elongates, the breech descends followed by the trunk and the after -coming head, i.e. spontaneous version occurs in the pelvic cavity. This requires very strong uterine contractions.Management

Antenatal A cause must be sought before deciding on a course of management. USG examination can detect the placenta previa or uterine abnormalities. Any these cause requires elective caesarean section. Once they have been exclude, ECVmay be attempt. It can be done in late pregnancy (beyond 35weeks) or even early in labour if the membranes are intact and vaginal delivery is feasible. In early labour, if version succeeded apply abdominal binder and rupture the membranes as if there are uterine contractions. If verson fails or is contraindicated:

The patient is to be admitted at 37th week, before risk of early rupture of the membranes and cord prolapse is very much there. Elective caesarean section is the preferred method of delivery.

Vaginal delivery may be allowed in a dead or congenitally malformed fetus.

During labour

If transverse lie is detected in early labour while the membranes are still intact and there is no contraindication, attempt Externalcephalic verson .If Externalcephalic verson is successful, proceed with normal childbirth..

If version fails or is contraindicated, deliver by caesarean section. In modern practice, CS is the best and safest method of management in all cases of persistent transverse or oblique lie even if the baby is dead.

Monitor for signs of cord prolapse. if cord prolapses and delivery is not imminent, delivery by caesarean section.

Note: As rupture of membranes carries the risk of cord prolapse, an elective caesarean section should be planned before labour commences.

Internal podalic version

It is mainly indicated in 2nd twin of transverse lie and followed by breech extraction.Prerequisites:

General or epidural anaesthesia.

Fully dilated cervix.

Intact membranes or just ruptured.

Neglected (Impacted) shoulder

Clinical picture (impending rupture uterus)

Exhaustion and distress of the mother.

Shoulder is impacted may be with prolapsed arm and / or cord.

Membranes are ruptured since a time.

Liquor is drained.

The uterus is tonically contracted.

The foetus is severely distressed or dead.

Management

Caesarean section is the safest procedure even if the baby is dead. A classical or low vertical incision in the uterus facilitates extraction of the foetus as a breech in such a condition.

Any other manipulations will lead eventually to rupture uterus so they are contraindicated