Malpresentation (face, brow)

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1. Malpresentation (face, brow)

2. Face presentation Face: chin to glabella Results when the head is hyperextended with the occiput touching the fetal neck All parts of the face from the chin to the glabella present in the pelvis Incidence is about 1/200-1/500 deliveries

3. Presentation Attitude Engaging diameter (cm) Denominator Vertex Complete flexion Subocciptobregmatic (9.5) Occiput Occipitoposterior Deflexion Occipitofrontal (11) Occiput Brow Partial extension Verticomental (13.5) Frontum Face Complete extension Submentobregmatic (9.5) Mentum

4. Key parameters and positions Denominator The mentum (chin) Attitude Complete extension Engaging diameter Submentobregmatic Possible positions Right mentoanterior (RMA) Left mentoanterior (LMA) Right mentoposterior (RMP) Left mentoposterior (LMP)

5. etiology Face presentation can be primary or secondary Primary face presentation Secondary face presentation Multiparity Abnormal pelvic configuration Fetal anomalies- Anencephaly Meningocele Dolichocephaly Tumors in the neck-thyroid enlargement, other tumors Spasm of extensor muscles of neck Loops of cord around neck Large baby Polyhydraminos Prematurity

6. Mechanism of labor ENGAGEMENT Submentobregmatic diameter engages in left or right oblique diameter Vertical diameter between face and the biparietal diameter > the vertical distance between the pelvic brim and ischial spines So the face is well below ischial spines when the bp diameter crosses the brim And the head is palpable per abdomen even after the face has descended below the level of ischial spines

7. DESCENT INCREASING EXTENSION- as the fetal trunk descends, extension of head increases

8. INTERNAL ROTATION- the mentum rotates anteriorly toward the pubic symphsis through 45 degrees in mentoanterior , and 135 degrees in mentoposterior . Rotation takes place at a lower level than in vertex presentation

9. FLEXION The chin hitches under the pubic symphysis and the mouth, nose, glabella , forehead, and occiput are born, in that order

10. RESTITUTION Neck untwists toward the opposite side EXTERNAL ROTATION Shoulders rotate toward the pubic symphysis

11. Complications of face presentation Maternal Fetal Prelabor rupture of membranes Congenital anomalies Prolapse of cord F etal heart rate anomalies Prolonged labor Facial edema Operative vaginal delivery Laryngeal/tracheal edema Caesarian section Admission to neonatal ICU

12. Diagnosis – abdominal examination Palpation Auscutation Umblical grip Back anterior in mentoanterior positions Back posterior at the flank in mentoposterior positions Fetal heart heard clearly in mentoanterior position Toward the flank in mentoposterior position Second pelvic grip Sinciput at higher level than occiput Groove felt between occiput and back Cephalic prominence on same side as back

13. Diagnosis- vaginal examination chin, mouth, malar eminences, nose, glabella felt Mentum in anterior or posterior quadrant

14. Progress in labor Labor progresses normally in mentoanterior positions since the engaging diameter is similar to that in vertex presentation Majority of the mentoposterior position also rotate anteriorly and deliver normally 25% may remain as mentoposterior or rotate to direct posterior

15. A persistent mentoposterior position cannot deliver vaginally

16. management Estimate weight of baby Perform internal pelvimetry Monitor Uterine contractions Descent of presenting part Fetal heart rate Cervical dilatation Station of presenting part rotation Mentoanterior If rotation is complete- normal or forceps If no rotation- caesarean section Mentoposterior If rotates anterior- normal If no rotation- caesarean section Oxytocin augmentation Only if baby weight average, pelvic configuration normal

17. Caesarean section is required if Fetus is large Mentum does not rotate anteriourly 1 hour after full dilatation Fetal heart rate abnormalities occur

18. Brow Brow- anterior fontanelles to supraorbital ridges In brow presentation all the structures from the orbital ridges to the anterior fontanelle are present at the pelvis

19. ETIOLOGY Most common Prematurity Multiparity Cephalopelvic disproportion (CPD) Others Tumour of neck Spasm of neck Polyhyrdoamnios

20. Course in labour Denominator – Frontum Attitude – Partial extension Engaging diameter – Vertico -mental(13.5) Positions LFA LFP RFA RFP VAGINAL DELIVERY NOT POSSIBLE (unless the fetus is very small or premature or the pelvis is very roomy)

21. Usually found early in labor With good contractions, flexes to vertex or extends to face presentation If it persists in established labor, there is no mechanism of labor or delivery If undiagnosed, can lead to rupture of uterus in multigravida

22. complications Maternal complications- premature rupture of membranes, prolapse of cord, if undiagnosed can lead to uterine rupture Fetal complications- related to associated anomalies, operative delivery and obstructed labor

23. diagnosis On abdominal examination, head feels broader Sinciput is higher than the occiput but not so high as in face presentation Diagnosis with certainty only on vaginal examination Anterior fontanelle , forehead, and orbital ridges are felt

24. management If diagnosed in early labor, the mother is monitored closely and vaginal exam repeated every 4-6 hours to see conversion If diagnosed in active labor, cesarean is indicated Oxytocin augmentation not recommended

25. reference Lakshmi seshadri