Malpresentation, Abnormal lie and Position Including Unstable lie

Most common type of malpresentation.

Causes/risk factors

Maternal

• In most cases, no apparent cause is discernable.
• Incidence is increased among multiparous women when compared to nulliparous women.
• Presence of pelvic tumors preventing the engagement of the presenting part increases the chances of breech presentation.
• Abnormalities of uterine shape
• Abnormalities of placentation
• Cephalopelvic disproportion

Fetal

• Prematurity
• Anencephaly
• Hydrocephalus
• Neck tumors
• Multiple pregnancies
• Polyhydraminos/oligohydramnios

Types

• Complete
• Frank
• Incomplete
• Footling

Diagnosis

Based on findings of a hard ballotable head in the upper segment of the uterus with the soft, round bottom in the lower uterine pole.

Diagnosis is confirmed using an ultrasound scan which may also show other abnormalities such as placenta previa, abnormal liquor volume, pelvic tumors, etc.

Management

Elective cesarean section

External cephalic version- carried out by trained providers in a setting that has ready access to a cesarean section.

Planned vaginal delivery might be possible in carefully selected women in whom unfavorable factors have been excluded and where appropriately trained personnel are on hand to conduct the delivery. It should only be offered in a facility with ready recourse to a cesarean section.

Occurs when the fetal head is hyperextended

Incidence is 1 in 500 labors

In early labor, minor deflexion occurs which may progress to hyperextension

Types of face presentation:

• Mentoanterior face 77% (commoner)
• Mentoposterior face

Presenting diameter is submento-bregmatic- 9.5cm

Etiology:

No cause could be found in >70%

• Anencephaly
• Multiple pregnancy
• Polyhydramnios
• Pelvic tumors
• Placenta previa
• Tumor of the fetal neck
• Commoner in multiparas

Diagnosis:

In early labor, the presenting part is high

Feel for the mouth, jaws, nose, malar and orbital ridges.

Mouth and maxillae form the corners of a triangle.

Delivery

For mentoanterior face-

• Spontaneous delivery/(augmentation)
• Lift-out forceps
• Vaginal delivery - 80%

Mentoposterior face-

• Augmentation
• Cesarean section commonly

Complications-

• Facial edema
• Bruises
• Soft tissue trauma

Incidence- 1 in 1050

Many brow presentation in labor are transient

Midway in position between face and vertex presentation

Proceeding to full deflexion = face presentation

Or undergo spontaneous flexion= vertex presentation

Mentovertical diameter is 13.5cm hence it cannot engage in normal pelvis

Causes-

Similar to face presentation

• Prematurity

Diagnosis

Vaginal examination-

• High presenting part
• Bregma occupies the centre of dilating cervix, -frontal suture, anterior fontanelle, and orbital region can be identified
• Nose, mouth and chin cannot be felt as in face presentation

Management

With persistent brow (average sized fetus and normal pelvis), engagement is impossible because of the wide presenting diameter

Presenting part is high

C/S is best option

Cord presentation: the umbilical cord is below the presenting part (head in the picture below but commonly a malpresentation) with the membranes intact.

Cord prolapse: the membranes have ruptured and the cord is beow the presenting part and has prolapsed into the vagina.

overall incidence of cord presentation is 0.1%-0.6%. It is much higher in breech presentation.

Risk factors

Factors preventing the proper fitting of the fetal presenting part predispose to cord prolapse. These include

• Abnormal lie
• Low birth weight
• Prematurity
• Second twin
• Polyhydramnios
• Low lying placenta

Other factors:

• Multiparity
• Procedures such as external cephalic version, internal podalic version, artificial rupture of membranes
• Use of large balloon catether for induction of labor.

Management of cord prolapse

Diagnosis is essentially clinical.

Electronic fetal monitoring can also be important for diagnosis when it is available. Abnormal FHR pattern following ROM may be the first indication of cord prolapse.

It is diagnosed by seeing or palpating the prolapsed cord on pelvic exam.

When diagnosed, summon a senior colleague and prepare operating theater for emergency delivery.

Management of cord presentation is usually by emergency C/S

Factors to consider-

• Is the fetus alive or dead?
• Lie/presentation
• Cervical dilatation

Live fetus –

• Attempt to prevent further cord compression by
• Elevating mother buttocks (knee chest position) or left lateral position
• Manually pushing the fetal head (presenting part) out of the pelvis
• Avoid handling the cord as this causes cord spasm.
• Fill the bladder with 500-700mls of normal saline
• Cephalic presenting fetus with cord prolapse
• Live fetus
• Cervix <8cm = c/s
• Cervix ≥ 8cm -assisted vaginal delivery
• Dead fetus –
• Expectant management (vaginal delivery)
• Destructive operation

Perinatal mortality associated with cord prolapse is high. These usually result from asphyxia caused by delay in effecting delivery.

One or more limbs precede or lie alongside with the head in vertex presentation.

Usually the arms or where one or both arms or hands present with breech

Causes:

Preterm

Twins pregnancy

Polyhydramnios

SROM with high presenting part

Diagnosis:

Diagnosis is easy. The limb and presenting part is felt occupying the pelvis

Management-

Expectant management (the arm usually rise into the uterus with contraction)