Malposition and malpresentations

for mbbs students

1. KUSHAL KUMAR MALPOSITION AND MALPRESENTATIONS

2. Definition Fetal presenting part other than vertex includes breech, face, brow, transverse, and compound presentation.

3. RISK FACTORS More than one pregnancy (e.g. Multipara,Grand multipara ) More than one fetus (e.g. Twins) Too much or too little amniotic fluid (e.g. Polyhydramnious , oligohydramnios) Abnormal uterine shape ( e.g. Arcuate ,septate, supseptate ) or abnormal growth ( e.g Fibroid) Placenta previa The baby is preterm

4. the part of the fetus which occupying the lower uterine segment Presentation Presentation may be : Breech 3 in 100 (3%) Face 1 in 500 (0.5%) Brow 1 in 1000 Shoulder 1 in 300 (0.3%) Compound 1 in 1000

5. Vertex 99% Face Brow

6. Occipitoposterior

7. Definition The occiput is in the posterior segment of pelvis, overlying the sacroiliac joint or the sacrum Occipitoposterior position is responsible for most cases of prolonged labour and second stage delay and is the most common cause of a mobile head at term When the occiput is in front of the sacrum, it is termed direct Occipitoposterior In the right Occipitoposterior, the occiput overlies the right sacroiliac joint and in left Occipitoposterior, it overlies the left sacroiliac joint Thus,3 positions are described –ROP, LOP, Direct Occipitoposterior

8. Aetiology 1. BACK ON THE RIGHT SIDE If the back is to the left as in 70% of vertex presentations, the chance of a posterior position(LOP) is remote this is because of dextrorotation of uterus and the presence of sigmoid colon on the left the foetal back is seen on the right side in 25-30% of vertex presentations and this predisposes to occipitoposterior (ROP) 2. ANTERIOR INSERTION OF PLACENTA Favours a posterior position by pushing the back of the head with the broader biparietal diameter posteriorly

9. 3. SHAPE OF THE BRIM Influences position In anthropoid pelvis, the anteroposterior diameter of the brim exceeds the transverse diameter This pelvis is usually of high assimilation type with an extra vertebra in the sacrum Therefore, inclination of the pelvis is increased and this favours Occipitoposterior In android pelvis, the inlet is wedge shaped and so the bulky occiput cannot find space in the narrow forepelvis This also predisposes to Occipitoposterior

10. DIAGNOSIS OF THE RIGHT OCCIPITOPOSTERIOR ABDOMINAL EXAMINATION Subumbilical flattening due to the absence of the back anteriorly Back is in one or the other flank and so cannot be felt clearly Limbs are felt easily anteriorly Shoulder is felt out in the flanks Unengaged or high head at term The sinciput and occiput may be at the same level due to deflexion Fetal heart sounds are heard in the flanks and are frequently indistinct

11. VAGINAL EXAMINATION Early in Labour Early rupture of conical bag of membranes Sagittal suture in the right oblique diameter of the pelvis Smaller posterior fontanelle in the right posterior quadrant and diamond shaped larger anterior fontanelle in the left anterior quadrant As the head is deflexed, both fontanelles are easily palpated

12. In occipitoanterior position, as the head is well flexed, the posterior fontanelle will be easily felt, but not the anterior fontanelle On the other hand, in Occipitoposterior, the head is usually deflexed and so the anterior fontanelle will also be felt with ease

13. LATE IN LABOUR A large caput may be present obscuring the sutures The pinna always points the occiput Perineum gapes much before the head distends it and premature straining can occur Difficulty in applying forceps in unrecognised occipitoposterior

14. MECHANISM OF LABOUR Occipitoposterior position is the common cause for prolonged labour in a vertex presentation The mechanism of labour will depend upon whether the vertex is well flexed. in occipitoposterior position with a well flexed head, the occiput being the lower will touch the pelvic floor first and rotate anteriorly and labour proceeds normally

15. However due to the longer internal rotation in occipitoposterior (3/8 of a circle) labour will naturally be prolonged In some occipitoposterior positions, the head is deflexed and this may result in further delay in rotation or malrotation

16. Deflexion may be due to when the back is posterior, the convexity of the fetal spine abuts against the convexity of the maternal spine causing extension of the head Hence large diameter present to the pelvic inlet and the occiput is no longer the leading part. This is also known as relative disproportion Another problem is that in OPP, the biparietal diameter occupies the smaller sacrocotyloid diameter which is encroached upon by the sacral promontory And hence the labour is further arrested

17. ENGAGING DIAMETERS Suboccipitofrontal diameter in a deflexed head is 10.5cm Occipitofrontal diameter in a head which is further deflexed is 11.5cm

18. COURSE OF LABOUR 1. Anterior rotation In 90% of cases, the occiput rotates anteriorly through 3/8of a circle and the baby is born as occipitoanterior . Engagement may be delayed and labour may be longer because of the dorsiflexion 2. Posterior rotation and face to pubis delvery When the head is deflexed, the engaging diameter is the occipitofrontal and sinciput is the leading part. Hence the sinciput touches the pelvic floor first and rotates anteriorly. The occiput thus rotates posteriorly into the hollow of sacrum and delivery occurs as face to pubis. Birth is by extreme flexion followed by extreme extension

19. Perineal tears are common as the occiput is posterior and it is the longer biparietal diameter(9.4), which distends the perineum rather than the smaller bitemporal (8cm). Hence liberal episiotomy should be given. 3 . Failure of rotation Persistent occipitoposterior is the absence of rotation and the head remains ROP or LOP Deep transverse arrest is defined as the head being arrested with the sagittal suture in the transverse diameter at the level of ischial spine, after full dilatation of cervix and in spite of good uterine contractions.

20. REASONS FOR FAILURE OF ROTATION Deflexion of the head Inefficient uterine contraction Weak pelvic floor preventing anterior rotation Cephalopelvic disproportion and android pelvis

21. MANAGEMENT Most of the malposition will rotate anteriorly and the baby will be born spontaneously as occiput anterior Alternatively, the may rotate posteriorly and deliver as face to pubis which need liberal episiotomy. As the labour is longer, judicious use of fluids and analgesia is needed. Epidural analgesia is ideal.

22. If the mother and baby are in good condition and labour is progressing well, there is no need for interference. A partogram assessment is essential and if progress is not satisfactory, the most common cause is inadequate uterine action . In inadequate uterine action, after excluding cephalopelvic disproportion, oxytocin augmentation is very useful in achieving rotation and delivery Caesarean section should be done in case of cehalopelvic dispropotion or if there is no progress even after oxytocin

23. MANAGEMENT OF DEEP TRANSVERSE ARREST 1. CAESAREAN SECTION The pelvis should be reassessed and if the pelvis is android or there is evidence of disproportion, CAESAREAN SECTION should be done Increasing use of caesarean for deep transverse arrest is to avoid the intracranial haemorrhage due to traumatic vaginal delivery

24. 2. VACCUM EXTRACTION This is an alternative in the absence of cephalopelvic disproportion. It promotes flexion thereby reducing the diameter presenting to the outlet from occipitofrontal to smaller suboccipitobrgmatic . It is less traumatic and does not need general anaesthesia The cup should be applied as near posterior fontanelle as possible as in order to promote flexion and smooth descent .

25. 3. MANUAL ROTATION This procedure can be employed if the obstetrician is well versed in this technique. Under the general anaesthesia, the right hand grasps the sinciput displacing it thereby increasing flexion. The smaller bitemporal diameter allows more space for the thumb and finger to have a firm grasp across the temple with middle finger on the frontal suture. In LOP, the left hand is used. Then the sinciput is rotated and forceps or vaccum is applied

26. 4. FORCEPS ROTATION In deep transverse arrest Keilland forceps is used. It should be used only by the obstetrician who are expert in its use. It is widely used in UK but it is not popular in India. Keilland forceps is applied under General Anaesthesia in the anteroposterior direction and rotation carried out

27. Face presentation

28. Definition This is a cephalic presentation where the attitude is one of complete extension, presenting part is the face (area between chin and glabella)and denominator is the chin or mentum . Primary face presentation : present before the onset of labour and are rare Secondary face presentation : caused by extension during labour .( E.g. . left mentoanterior is a result of extension of right Occipitoposterior)

29. The engaging diameter is submentobregmatic 9.4 cm

30. Positions

31. Etiology Maternal Contracted pelvis Oblique of uterus Multiparity and pendulous abdomen Fetal Anencephaly and iniencephlaly Cord round neck Tumor of neck like congenital goiter Spasm of sternocleidomastoid muscle Dolichocephalic head

32. Diagnosis Abdominal examination In mentoanterior , back is felt with difficulty as it is posterior and limbs are felt anteriorly Head remains high Cephalic prominence is the occiput and on the same side as the back Groove between the head and back is prominent Fetal heart sound are transmited through the chest and heart well anteriorly in mentoanterior

33. Vaginal examination Conrical bag of membranes Chin, mouth, nose, mala eminences, and supraorbital ridges are felt In mentoanterior , chin is in one anterior quadrant and forehead in the opposite posterior quadrant

34. Mechanism of labour Mentoanterior posterior Engagement the engagement diameter is submentobregmatic . In face presentation, the biparietal diameter is 7 cm behind the face unlike in vertex, where it is only 3-4 cm distance. The biparietal diameter will pass through the inlet only when the face is low down in the perineum. When the face is distending the vulva (crowning), the head has just engaged.

35. 2. Descent with increasing extension Descent is brought by the same factors as in vertex presentation. When resistance is encountered by a process of extension, the occiput is pushed towards the back of the fetus, while the chin descents.

36. 3. Internal rotation On further descent, the chin reaches the pelvic floor and rotates anteriorly through 45 towards the symphysis. Anterior rotation does not take place until the face is well applied to the pelvic floor and may be delayed. Only internal rotation takes place this manner, can the neck travers the posterior surface of the symphysis pubis.

37. 4. flexion The head is born by flexion. The chin pivots under the symphysis pubis and the mouth, nose, orbits, forehead, vertex and occiput are born by flexion 5.Restitution and external rotation Restitution and external rotation of chin occurs towards the side to which it was originally directed, and the shoulder are born as in vertex

38. Mentoposterior position 2/3 of cases anteriorly through 3/8 of a circle and deliver as mentoanterior . Of the rest, some remain in the oblique diameter and some rotate posteriorly into the hollow of sacrum. In these cases of persistent mentoposterior , the neck is too short to span the 12cm of the anterior aspect of sacrum.

39. The shoulder also get impacted along with the head making delivery impossible. The engaging diameter is the sternobregmatic , which is about 17cm. Hence, there is no mechanism of labour in mentoposterior

40. Cause of prolonged labour in face Face is less effective dilator of cervix No moulding of face More chance of premature rupture of membrane Long internal rotation in mentoposterior Internal rotation occurs only late in the second stage

41. complication Rupture of fetal membranes cord prolapse → fetal distress →fetal death edema of the brow marked moulding , congenital malformation Increase in maternal and fetal morbidity and mortality prolonged and complicated labour Maternal distress … dehydration … keto acidosis Infection obstructed labour → uterine rupture → maternal death Maternal complication Fetal complication

42. Management of labour Evaluate the cephalopelvic disproportion or other associated complication and in such situation, caesarian section is done. If there is no disproportion and position is mentoanterior , labour can be allowed to progress. In persistent mentoposterior , cescerian section is done.

43. Brow presentation

44. Definition It is the least common among cephalic presentation and most unfavorable. The attitude is one of partial extension , the presenting part being the area between the anterior fontanelle( bregma ) above and the glabella and orbital ridges bellow and denominator is the forehead or frontum .

45. The presenting diameter is verticomental 13.5 cm, which is largest of fetal head

46. Incidence and etiology It is about 1in 1000 birth The cause is similar to face presentation and include any factor that interferes with flexion of the head

47. Possible Etiological causes Bicornate uterus Septet uterus Fibroid uterus Pelvic tumor Non gynaecoid pelvis Maternal Prematurity Multiple gestation Polyhydramnios Oligohydramnios Large Fetus Large Fetal head Congenital Abnormalities Cord around the neck Neck tumor Fetal

48. There are 4 main positions - Left fronto-anterior. - Right fronto-anterior. - Right fronto-posterior. - Left fronto-posterior.

49. diagnosis Abdominal examination High mobile head, which feels large from side to side Cephalic prominence is the occiput and is on the same side as the back and the groove between the cephalic prominence and the back is less prominent than in face presentation

50. Vaginal examination Conical bag of membrane may be felt in early labour Anterior fontanelle( bregma ) is felt at one end and root of nose( nasion )and orbit ridges at the other end of an oblique or transvers diameter. Sometimes, the nose and the mouth are palpable, but not the chin.

51. Machanism of labour As such, ther is no mechanism of labour for persistent brow presentation. Spontaneous delivery is unlikely and can occur only when there is a very small baby and large pelvis. In persistent brow, the verticomental diameter is shortened and the occipitofrontal diameter is elongated with marked moulding and a large catput on the forehead

52. complication Rupture of fetal membranes cord prolapse → fetal distress →fetal death marked molding Increase in maternal and fetal morbidity and mortality prolonged and complicated labour Maternal distress … dehydration … keto acidosis Infection No engagement of presenting part obstructed labour → uterine rupture →maternal death Maternal complication fetal complication

53. Management Antepartum It is better to wait until the onset of labour in the hope that correction to vertex or face. Early labour Cesarean section should be done. If diagnosis in early labour before rupture of membrane, a short period of time can be given under close supervision in the hope of spontaneous correction.

54. Late labour It there is feature of obstructed labour , cesarean section is performed immediately even if the fetus is dead.

55. Thank you