Obstetrics: Malpresentations and Malpositions

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Questions and Answers

What is the success rate of External Cephalic Version for multiparous women?

60% (correct)

70%

50%

40%

External Cephalic Version can be performed after 36 weeks for primigravida and after 37 weeks for multigravidas.

True

What is a contraindication for External Cephalic Version related to fetal causes?

hyperextension of the head

Successive attempts of External Cephalic Version cannot exceed ______ in a span of 10 minutes.

4 Signup and view all the answers

Match the ECV procedure with its corresponding action:

Tocolysis = inj. Terbutaline 250 mcg s/c or inj. Salbutamol 250mc slow IV infusion Monitoring = FHR with USG After ECV = women are at increased risk for operative delivery Face Presentation = Operative delivery and vaginal manipulation Signup and view all the answers

What is the definition of presentation in the context of fetal position?

Refers to the part of the fetus which occupies the lower pole of the uterus. Signup and view all the answers

What are some risk factors associated with malpresentations?

Uterine anomalies, abnormal placental location, congenital anomalies of fetus, high parity with pendulous abdomen, contracted pelvis, pelvic tumors, prematurity, polyhydramnios. Signup and view all the answers

What are the different types of breech presentations mentioned?

Frank breech Signup and view all the answers

The denominator for breech presentation is the ________.

sacrum Signup and view all the answers

Hyperextension of the neck beyond 270 degrees in a breech presentation fetus is safe for vaginal delivery.

False Signup and view all the answers

What position is recommended to avoid cord compression during labor?

Left lateral/ exaggerated Sims position/ pillow under the hip Signup and view all the answers

What is the percentage incidence of occiput-posterior presentation among all vertex presentations?

10% Signup and view all the answers

In occiput-posterior presentation, is the posterior fontanelle easy to reach?

False Signup and view all the answers

Occiput-posterior position carries a risk of ______ delivery.

face to pubis Signup and view all the answers

Match the following methods with their uses in labor management:

Ventouse = Promotes flexion, applied close to posterior fontanelle Manual Rotation = Under general anaesthesia, successful rotation followed by Mid-forceps extraction Signup and view all the answers

What are some indications for the use of ultrasound in labor?

<ol> <li>Objective assessment of fetal head malpresentation</li> <li>Slow progress or arrest of labor in first stage / second stage</li> <li>Ascertainment of fetal head position and station before considering or performing instrumental vaginal delivery</li> </ol> Signup and view all the answers

Study Notes

Malpresentations and Malpositions

Definition: Malpresentations refer to the part of the fetus that occupies the lower pole of the uterus, other than vertex, such as breech, brow, face, or shoulder.
Denominator: Arbitrary bony fixed point on the presenting part.
Position: Relationship of denominator to different quadrants of the pelvis.

Risk Factors for Malpresentations

Uterine anomalies (can be detected at first trimester scans)
Abnormal placental location
Congenital anomalies of the fetus
High parity with pendulous abdomen
Contracted pelvis
Pelvic tumors
Prematurity
Polyhydraminos

Breech Presentation

Definition: Breech presentation is when the sacrum is the denominator.
Incidence: 20-25% at 28 weeks, 3-5% at term.
Incidence in consecutive pregnancies: 9, 25, and 40% respectively.
Risk factors: Prematurity, oligohydramnios, placenta previa, congenital malformation of the uterus, hydrocephalus, contracted pelvis, and cornu-fundal attachment of the placenta.

Types of Breech Presentation

Frank breech: 60-70% (more common in primigravidas)
Complete breech: 5-12% (more common in multigravidas)
Footling breech: 10-30% (risk of cord prolapse 12%)

Mechanism of Labor in Breech Presentation

Sacro-anterior position
Engagement (bitrochanteric diameter)
Descent with compaction (flexion)
Internal rotation
Flexion
Internal rotation
Delivery by lateral flexion

Breech Vaginal Delivery

Spontaneous breech vaginal delivery: 10%
Partial breech extraction/assisted breech extraction: 80-90%
Total breech extraction: requires experienced obstetrician and anesthetist

Pinard's Manoeuvre

For frank breech extraction
Posterolateral aspect of the thigh
Presses fingers into the popliteal fossa, abducts the thigh

Lovset's Manoeuvre

For extended arms/nuchal arm
Inclination of the pelvis allows for entry of the posterior shoulder first into the pelvis
Principle: Rotate the body counterclockwise for right nuchal arm and clockwise for left nuchal arm

Star-Gazing Fetus

Hyperextension >270 degrees
5% term breech fetus
Vaginal delivery can result in Atlanto-occipito dislocation
Indication for caesarean section

Dührssen Incision

Head entrapment due to incomplete cervical dilatation
2, 6, and 10 o'clock position

Term Breech Trial 2000

Randomized controlled multicentric trial
2088 women, 121 centers, 26 countries
Planned caesarean section is better than planned vaginal birth
Perinatal mortality 3 per 1000 (planned caesarean section) vs 13 per 1000 (planned vaginal birth)

Premoda 2006

Presentation et Mode d'Accouchement (presentation and mode of delivery)
8,105 women, observational prospective study
Caesarean delivery 68.8%, vaginal delivery 31.2%
No differences in neonatal mortality rates and neonatal outcomes according to delivery mode
Planned vaginal delivery can be offered to term breech

Adverse Outcomes of Vaginal Breech Delivery

Overall perinatal mortality 9-25%
Birth asphyxia
Birth injuries
Intracranial hemorrhage
Long-term abnormalities

Indications for Caesarean Section

Complicated breech (placenta previa, pre-eclampsia, contracted pelvis)
Footling/incomplete breech
EFW 3500 gms, BPD >9.5 cm
Hyperextension of the neck, craniospinal angle >90
Previous caesarean section
Fetal anomaly that can result in shoulder dystocia

Breech Scoring System

To be discussed

External Cephalic Version (ECV)

Success rate: Multiparous 60%, primigravida 40%
Increased success rates with nonobese patients, abundant amnionic fluid, and nonanterior placenta
Indications: >36 weeks (primi), >37 weeks (multigravidas), singleton pregnancy, no GCA/FGR, liquor adequate, and membranes present
Contraindications: antepartum hemorrhage, fetal causes, multiple pregnancy, ruptured membranes, congenital malformation of the uterus, abnormal CTG, and contracted pelvis
Procedure: Tocolysis, epidural analgesia, forward roll, and back flip### Face Presentation
Incidence: 1 in 500 births
Attitude: complete flexion with spine extension (occiput in contact with the back)
Denominator: Mentum
Risk factors:
- Multiparity with pendulous abdomen (70%)
- Congenital anomalies (15%)
- Placenta previa/cornual implantation of placenta
- Coils of cord around neck
- Pelvic tumor
Palpation and vaginal examination (P/V): the mouth, hard alveolar margins, nose, malar eminences, supraorbital ridges, and mentum
Maternal prognosis: operative delivery and vaginal manipulation
Fetal prognosis: cord prolapse, cerebral congestion due to poor venous return, neonatal infection

Mechanism of Labour

Mento-anterior: 60-80%
- Engagement: submento-bregmatic
- Descent: with extension
- Internal rotation: late, below the ischial spines
Mentoposterior: 20-25%
- Engaging diameter: sub-mentobregmatic (9.5cm) or submento-vertical (11.5cm)
- Long anterior rotation: 20-30%
- Incomplete anterior rotation/non-rotation/short posterior rotation: 70-80%

Brow Presentation

Incidence: 1 in 1000
Engaging diameter: mentovertical (14cm)
Denominator: Forehead
Palpation and vaginal examination (P/V): supraorbital ridges and anterior fontanel
Brow anterior: baby is small, the pelvis is roomy, good uterine contractions
Brow posterior: not possible
Thorns maneuver: turn brow into vertex, walking fingers over the head

Shoulder Presentation

Incidence: 1 in 150
Lie: transverse
Denominator: Acromion of scapula
Etiology:
- Multiparity (80%)
- Placenta previa (5-10%)
- Prematurity
- Uterine malformations
- LUS fibroid
Palpation and abdominal examination (P/A): ballotable head is felt in one iliac fossa
Palpation and vaginal examination (P/V): acromion process, scapula, clavicle, and axilla
Position: dorso-anterior (60%), fetus is flexed
Complications:
- High chances of hand and cord prolapse
- Uterine exhaustion/rupture
- Dehydration/ketoacidosis/shock/sepsis/peritonitis

Prognosis in Shoulder Presentation

Overall perinatal mortality: 25-50% (vaginal delivery), 7% (caesarean delivery)
Maternal morbidity: increased operative delivery, sequences of neglected shoulder

Management of Shoulder Presentation

External cephalic version: all cases beyond 35 weeks
Admitted at 37th week: elective cesarean section is the preferred method of delivery

Compound Presentation

Incidence: 1 in 350 to 1 in 1200
Most common cause: preterm labor
Other causes: contracted pelvis, pelvic tumors, multiple pregnancy, macerated fetus
Spontaneous resolution: elevation of the prolapsed limb with descent of the presenting part
Complications:
- Cord prolapse
- Indication for caesarean section

Cord Presentation

Incidence: 1 in 300
Membranes intact: cord presentation
Membranes rupture: cord prolapse
Management:
- Left lateral/exaggerated sims position/pillow under the hip
- Foleys catheterization
- Referral: caesarean delivery

Occiput-Posterior Presentation

Incidence: 10% of all vertex presentations, 2% in late stages
Causes:
- Android or anthropoid pelvis (50%)
- Deflexed head (high pelvic inclination)
- Anterior placenta
- Primary brachycephaly
Palpation and abdominal examination (P/A): suprapubic flatness, head high, late engagement, occiput and sinciput at the same level
Palpation and vaginal examination (P/V): posterior fontanelle is difficult to reach
Mechanism of labor:
- Delayed engagement (deflexed head, occiput-frontal 11.5cm, sub-occpitofrontal 10.5cm)
- Flexion
- Descent
- Internal rotation (3/8th of circle)
- Long anterior rotation; 90%
- Short posterior rotation
- Non-rotation
Complications:
- Perineal tear
- Sagittal suture in oblique diameter, oblique posterior arrest

Labour Events in Occiput-Posterior

First stage: prolonged, delayed engagement, premature rupture of membranes
Management:
- Adequate hydration
- Premature rupture of membranes
- Maintain partograph
- Augmentation of labour (r/o CPD)
- Avoid premature bearing down effort
Second stage: prolonged, prolonged bearing down effort
Management:
- Frequent bladder emptying
- Avoid poor uterine contractions
Third stage: PPH, perineal tears (occiput-frontal diameter distends perineum)

Deep Transverse Arrest

Definition: adequate uterine contractions, at full dilatation, head remains at level of ischial spines for >1 hour (multi), >2 hours (primi)
Causes: android pelvis
Options:
- Ventouse
- Forceps (Kielland)
- Manual rotation (not used)
- Caesarean section

ISOUG Guidelines

Indications for USG in labour:
- Objective assessment of fetal head malpresentation
- Slow progress or arrest of labour in first stage/second stage
- Ascertainment of fetal head position and station before considering or performing instrumental vaginal delivery
Assessment of fetal head position:
- AoP/angle of descent
- Midline angle

Final Takeaway

Breech presentation: always maintain flexion while delivering head; keep back anterior
Face presentation:
- Mentoanterior: head born by flexion
- Mentoposterior: Caesarean
Brow presentation: Caesarean
Direct Occiput-posterior: face to pubis delivery

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Description

This quiz covers the different types of malpresentations and malpositions in obstetrics, including breech, face, brow, and shoulder presentations. It also discusses risk factors, diagnosis, and management.