Malposition -Reproductive Health Lecture Notes
Download as PPTX, PDF3 likes269 views
The document discusses the occipito-posterior position (OP) during labor, an abnormal vertex position occurring in about 10% of labors, often leading to prolonged labor due to failed internal rotation. It outlines factors contributing to OP, diagnostic methods, potential complications, and management strategies including observation, manual rotation, and cesarean sections. The prognosis indicates increased maternal and perinatal morbidity, with careful monitoring and timely intervention being crucial to mitigate risks.
![Unlike the occipitoanterior, the course of events in labor is likely to be modified in
occipitoposterior
position. The average duration of both the first and second stage of labor is
increased.
First stage: There is tendency to delay.
(1) Engagement: Engagement is delayed due to:
(i) Persistence of deflexion of the head thereby increasing the diameter of engagement
[occipitofrontal-11.5 cm].
(ii) (ii) The driving force transmitted through the fetal axis is not in alignment with the
axis of the inlet.
(2) Membrane status: Deflexed head becomes ovoid and this cannot fit well to the
spherical lower segment leading to loss of ball valve action during uterine contraction hence
early rupture of the membranes and drainage of liquor.
(3) Uterine contraction: Because of ill-fitting of the deflexed head to the lower uterine
segment, there is lack of stimulus for uterine contraction. This results in abnormal uterine
contraction with slow dilatation of the cervix. Pressure on the rectum by the wide occiput
results in premature desire of bearing down effort even in the first stage. The patient
becomes exhausted. There is prolongation of the first stage.
7/5/2021 9:17 AM
©Siambi,2021™ 22](https://image.slidesharecdn.com/malpositiongroupfive-210705091704/85/Malposition-Reproductive-Health-Lecture-Notes-22-320.jpg)
Malposition -Reproductive Health Lecture Notes
- 2. Malposition refers to any position of the vertex other than flexed occipitoanterior one. In a vertex position where the occiput is placed posteriorly over the sacro-ilical joint or directly over the sacrum, it is called an occipito-posterior position. When the occiput is placed over the right sacroiliac joint, the position is called right occipito posterior (R.O.P) position and when placed over the left sacro-iliac joint, is called left occipito posterior (L.O.P) position. 7/5/2021 9:17 AM ©Siambi,2021™ 2
- 3. Occipito-posterior position is an abnormal position of the vertex rather than an abnormal presentation. Occurs in approximately 10% of labors. The incidence is expected to be more during late pregnancy and is much less in late second stage of labor. A persistent occipito-posterior position results from a failure of internal rotation prior to birth. Occurs in 5% of the births. ROP is five times more common than LOP 7/5/2021 9:17 AM ©Siambi,2021™ 3
- 5. The direct cause is often unknown. But the following are the responsible factors: i) Shape of the pelvic inlet: associated with either an anthropoid or android pelvis. ii) Fetal factors: Marked deflexion of fetal head.Often favors posterior position of the vertex. Causes of deflexion are: (1) High pelvic inclination. (2) Attachment of the placenta on the anterior wall of the uterus (3) primary brachycephaly-this shortens the length of the lever from the frontal to atlantooccipital joint, and thereby diminishes the effective movement of flexion. iii) Uterine factors: Abnormal uterine contraction 7/5/2021 9:17 AM ©Siambi,2021™ 5
- 6. Listen to the mother(Hx): Complain of backache and she may feel that her baby’s bottom is very high up against her ribs. ABDOMINAL EXAMINATION Inspection: • Abdomen looks flat, below the umbilicus. • Presence of saucer shaped depression. • The outline created by high, unengaged head can look like a full bladder 7/5/2021 9:17 AM ©Siambi,2021™ 6
- 7. Palpation: • Fetal limbs are felt more easily near midline on either side. •Fetal back is felt far away from midline on flank. • Anterior shoulder lies far away from midline. • Head is not engaged. • Cephalic prominence is not felt so much prominent Auscultation: • The fetal back is not well flexed so chest is thrust forward, therefore the fetal heart can be heard in the midline. • Heart rate may be heard more easily at the flank on the same side as the back. 7/5/2021 9:17 AM ©Siambi,2021™ 7
- 9. VAGINAL EXAMINATION • Elongated bag of membranes •Sagittal suture occupies any of the oblique diameters of pelvis. • Posterior fontanelle is felt near the sacro-iliac joint • Anterior fontanelle is felt more easily 7/5/2021 9:17 AM ©Siambi,2021™ 9
- 10. In late labor, the diagnosis is often difficult because of caput formation which obliterates the sutures and fontanels. In such cases, the ear is to be located and unfolded pinna points toward the occiput. Imaging: Ultrasonography is rarely done. It is helpful to know the descent, attitude of the head and its relation to the pelvic walls (position). 7/5/2021 9:17 AM ©Siambi,2021™ 10
- 11. Head engages through right oblique diameter in ROP and left oblique diameter in LOP. The engaging transverse diameter of head is biparietal (9.5 cm) and that of anteroposterior(AP) diameter is either suboccipitofrontal (SOF)-10 cm or occipitofrontal (OF)-11.5 cm. Because of deflexion engagement is delayed. 7/5/2021 9:17 AM ©Siambi,2021™ 11
- 13. In Favorable Circumstances (90%) i) Flexion: Good uterine contractions result in good flexion of the head. Descent occurs until the head reaches the pelvic floor. ii) Internal rotation of the head: As the occiput is the leading part, it rotates 3/8th of a circle (135°) anteriorly to lie behind the symphysis pubis. As the neck cannot sustain such amount of torsion(twisting), the shoulders rotate about 2/8th of a circle to occupy the right oblique diameter in ROP and the left oblique in LOP with 1/8th of a circle torsion of the neck still left behind. iii) Further descent and delivery of the head occurs like that of occipitoanterior position. iv) Restitution: There is movement of restitution to the extent of 1/8th of a circle in the opposite direction of internal rotation of the head. v) External rotation: The external rotation of the head occurs through 1/8th of a circle in the same direction of restitution as the shoulders rotate from the oblique to anteroposterior diameter of the pelvis. vi) Birth of the shoulders and trunk: The process of expulsion is the same as that of occipitoanterior. 7/5/2021 9:17 AM ©Siambi,2021™ 13
- 14. In unfavorable circumstances: (Nonrotation or malrotation)-10%. In certain circumstances, the occiput fails to rotate as described previously. The causes are: i) deflexion of the head (sinput meets the pelvic floor,rotates 1/8 ), ii) weak uterine contraction, iii) faulty shape of the pelvis such as flat sacrum, iv) prominent ischial spines or convergent side walls and weak pelvic floor muscles. v) Big baby and immobility of the fetal trunk consequent to the drainage of liquor. 7/5/2021 9:17 AM ©Siambi,2021™ 14
- 15. Incomplete forward rotation: In this condition, the occiput rotates through 1/8th of a circle anteriorly and the sagittal suture comes to lie in the bispinous diameter. Thereafter, further anteriorrotation is unlikely and arrest in this position is called deep transverse arrest. Nonrotation: Both the sinciput and the occiput touch the pelvic floor simultaneously due to moderate deflexion of the head resulting in nonrotation of the occiput. The sagittal suture lies in the oblique diameter. Further mechanism is unlikely and the condition is called oblique posterior arrest. Malrotation: In extreme deflexion, the sinciput touches the pelvic floor first resulting in anteriorrotation of the sinciput to 1/8th of a circle and putting the occiput to the sacral hollow. This position is termed as occipitosacral position. This is, “Persistent Occipitoposterior Position” (POP) of the vertex. 7/5/2021 9:17 AM ©Siambi,2021™ 15
- 17. Further descent occurs until the root of nose hinges under symphysis pubis. Flexion occurs —releasing successively the brow, vertex and occiput out of the stretched perineum and then the face is born by extension. Restitution: Head moves 1/8th of circle in opposite direction of internal rotation thus turning the face to look towards the mother’s left thigh in ROP and right thigh in LOP. External rotation: Occiput further rotates to the same direction of restitution to 1/8th of a circle placing finally face looking directly towards the left thigh in ROP and the right thigh in LOP. 7/5/2021 9:17 AM ©Siambi,2021™ 17
- 18. It is an abnormal mechanism of the occipito posterior position where there is malrotation of the occiput posteriorly towards the sacral hollow. Delivery may occur spontaneously as face to pubis but arrest may occur in this position and is called occipito sacral arrest Cause: Failure of flexion 7/5/2021 9:17 AM ©Siambi,2021™ 18
- 22. Unlike the occipitoanterior, the course of events in labor is likely to be modified in occipitoposterior position. The average duration of both the first and second stage of labor is increased. First stage: There is tendency to delay. (1) Engagement: Engagement is delayed due to: (i) Persistence of deflexion of the head thereby increasing the diameter of engagement [occipitofrontal-11.5 cm]. (ii) (ii) The driving force transmitted through the fetal axis is not in alignment with the axis of the inlet. (2) Membrane status: Deflexed head becomes ovoid and this cannot fit well to the spherical lower segment leading to loss of ball valve action during uterine contraction hence early rupture of the membranes and drainage of liquor. (3) Uterine contraction: Because of ill-fitting of the deflexed head to the lower uterine segment, there is lack of stimulus for uterine contraction. This results in abnormal uterine contraction with slow dilatation of the cervix. Pressure on the rectum by the wide occiput results in premature desire of bearing down effort even in the first stage. The patient becomes exhausted. There is prolongation of the first stage. 7/5/2021 9:17 AM ©Siambi,2021™ 22
- 23. Second stage: The second stage is often delayed due to long internal rotation or malrotation, with at times, arrest of the head. This may happen in android pelvis or in midpelvic contraction. If felt uncared for, arrest of the head may lead to obstructed labor. Third stage: There is increased incidence of postpartum hemorrhage and trauma of the genital tract. 7/5/2021 9:17 AM ©Siambi,2021™ 23
- 24. Long anterior rotation of the occiput: Spontaneous or aided vaginal delivery usually occurs (90%) Short posterior rotation: Spontaneous or aided vaginal delivery may occur as face to pubis. Non-rotation or short anterior rotation: Spontaneous vaginal delivery is unlikely except in favourable circumstances. Moulding: The characteristic moulding of head occurs in face to pubis delivery. There is compression of the occipito-frontal diameter with elongation of the vault at right angle to it. The frontal bones are displaced beneath the parietal bones. 7/5/2021 9:17 AM ©Siambi,2021™ 24
- 25. Prognosis: Increased maternal morbidity, incidental to prolonged labor and increased incidence of operative delivery (1 in 5). Increased perinatal morbidity and mortality (10%) due to asphyxia or trauma during vaginal operative delivery 4 out of 5 cases there is usually no trouble and the fetus is delivered spontaneously. 7/5/2021 9:17 AM ©Siambi,2021™ 25
- 26. Principles: The underlying principles in the management of the occipitoposterior position are;- i) early diagnosis, ii) strict vigilance with watchful expectancy hoping for descent and anterior rotation of the occiput, iii) iii) judicious and timely interference, if necessary. 7/5/2021 9:17 AM ©Siambi,2021™ 26
- 27. Diagnosis and evaluation: Fetal back on the flank with the FHS not being easily located, early rupture of the membranes should arouse suspicion. Internal examination is confirmatory Pelvic assessment: Inclination of pelvis, configuration of inlet, sacrum, ischial spines and the side walls are to be noted. Early cesarean section: Occipitoposterior is not an indication of cesarean section. Pelvic inadequacy or its unfavorable configuration, along with obstetric complications such as, preeclampsia, post-cesarean pregnancy, big baby usually need cesarean section. 7/5/2021 9:17 AM ©Siambi,2021™ 27
- 28. Anticipating prolonged labor, intravenous infusion line is sited and Ringer’s solution drip is started. Progress of labor is judged by- (a) progressive descent of the head (b) rotation of the back and the anterior shoulder toward the midline, (c) increasing flexion of the head, (d) position of the sagittal suture on vaginal examination’ (e) cervical dilatation. Weak pain, persistence of deflexion and nonrotation of the occiput are the triad too often coexistent. In such a situation, oxytocin infusion is started for augmentation of labor. Indication of cesarean section: (a) Arrest of labor (failure of rotation), (b) incoordinate uterine action and (c) fetal distress 7/5/2021 9:17 AM ©Siambi,2021™ 28
- 29. In minority: watchful expectancy for anterior rotation of the occiput and descent of the head. In occipito-sacral position, spontaneous delivery of face to pubis may occur. 7/5/2021 9:17 AM ©Siambi,2021™ 29
- 30. Tendency of PPH can be prevented by prophylactic IV ergometrine 0.25 mg with the delivery of anterior shoulder. Following vaginal delivery meticulous inspection of the cervix and lower genital tract should be made to detect any injury. 7/5/2021 9:17 AM ©Siambi,2021™ 30
- 31. If there is failure to progress (arrest) in spite of good uterine contractions for about 1/2–1 hour after full dilatation of the cervix, interference is indicated. The case is once more to be assessed abdominally and vaginally before formulating the suitable method of interference. Per abdomen: The following conditions are assessed: (1) Size of the baby, (2) Engagement of the head, (3) Amount of liquor, (4) FHS. 7/5/2021 9:17 AM ©Siambi,2021™ 31
- 32. Vaginal examination: The following conditions are to be noted- (1) Station of the head, (2) Position of the sagittal suture and the occiput, (3) Degree of deflexion of the head, (4) Degree of molding and caput formation, (5) Assessment of the pelvis at and below the level of obstruction, i.e. ischial spines, side walls of the pelvis, sacrococcygeal plateau, pubic arch and transverse diameter of the outlet. I. ARREST IN OCCIPITOTRANSVERSE OR OBLIQUE OCCIPITOPOSTERIOR POSITION (1) Ventouse (Vacuum extraction): It is suitable in cases where the pelvis is adequate and the nonrotation of the occiput is either due to weak contractions or lack of tone of pelvic floor muscles. 7/5/2021 9:17 AM ©Siambi,2021™ 32
- 33. (2) Cesarean section: If the case is unsuitable for manual rotation especially in the presence of midpelvic contraction, cesarean section is much safer even at this stage. (3) Alternative methods (a) Manual rotation followed by forceps extraction: The objectives are first to rotate the head manually until the occiput is placed behind the symphysis pubis and secondly in that position forceps blades are applied. The pelvis should be adequate; the baby is of average size and there is good amount of liquor. (b) Forceps rotation and extraction: In the hands of experts, forceps rotation followed by extraction can be achieved by using Kielland forceps. Its advantages over manual rotation are- (1) no chance of displacement of the head, (2) accidental cord prolapse is absent and (3) rotation can be done at, above or below the level of obstruction depending upon the type of pelvis. (c) Craniotomy: The dead baby should be delivered by craniotomy. 7/5/2021 9:17 AM ©Siambi,2021™ 33
- 34. II. OCCIPITOSACRAL ARREST If the head is engaged and the occiput descends below the ischial spines, forceps application in unrotated head followed by extraction as face-to-pubis is an effective procedure. Liberal mediolateral episiotomy should be done. If the occiput remains at or above the level of ischial spines, cesarean section should be considered. 7/5/2021 9:17 AM ©Siambi,2021™ 34
- 35. The head is deep into the cavity, the sagittal suture is placed in the transverse bipsinous diameter and there is no prognosis in descent of the head even after ½ -1 hour following full dilatation of cervix. May be end result of incomplete anterior rotation of the oblique OPP, or it may be due to non rotation of the commonly primary occipito transverse position of normal mechanism of labour. 7/5/2021 9:17 AM ©Siambi,2021™ 35
- 36. Faulty pelvic architecture Prominent ischial spine, Flat sacrum and convergent side walls, Deflexion of head, Weak uterine contraction, Laxity of the pelvic floor muscles. 7/5/2021 9:17 AM ©Siambi,2021™ 36
- 37. Head is engaged Sagittal suture lies in transverse bispinous diameter, Anterior fontanelle is palpable, Faulty pelvic architecture may be detected 7/5/2021 9:17 AM ©Siambi,2021™ 37
- 38. 1. Vaginal delivery is found not safe (big baby and or inadequate pelvis): Cesarean section. 2. Vaginal delivery is found safe (any of the methods may be employed): i) Ventouse-Excessive traction force should not be used. ii) Manual rotation and application of forceps. iii)Forceps rotation and delivery with Kielland in the hands of an expert. Note: Operative vaginal delivery for DTA should only be performed by a skilled obstetrician. Otherwise cesarean delivery is always preferred. 7/5/2021 9:17 AM ©Siambi,2021™ 38
- 39. Steps: The patient is put under general anesthesia and in lithotomy position. Full surgical asepsis is maintained. Bladder is catheterized. Vaginal examination is done to identify the direction of the occiput. If a big caput has been formed, the direction of the unfolded pinna of the ear which points toward the occiput, can be taken for help. WHOLE HAND METHOD: Whole of the hand is introduced inside the vagina for rotation. Step—I: Gripping of the head: In ROP or ROT the left hand and in LOP or LOT, the right hand is usually used. The corresponding hand is introduced into the vagina in a cone-shaped manner after separating the labia by two fingers of the other hand. In occipitotransverse position, the four fingers are pushed in the sacral hollow to be placed over the posterior parietal bone and the thumb is placed over the anterior parietal bone. In oblique posterior position, the four fingers of partially supinated hand are placed over the occiput and the thumb is placed over the sinciput . 7/5/2021 9:17 AM ©Siambi,2021™ 39
- 40. Step—II: Rotation of the head: Slight disimpaction may be needed for good grip. By a movement of pronation of the hand, the head is rotated to bring the occiput anterior along the shortest route. Simultaneously, the back of the fetus is rotated by the external hand from the flank to the midline. This is an essential prerequisite for anterior rotation of the head. A little over rotation is desirable anticipating slight recurrence of malposition before the application of forceps. In the alternative method, the four fingers of the pronated right hand are placed over the sinciput and the thumb over the occiput in ROP. The head is rotated by supination movement of the hand. 7/5/2021 9:17 AM ©Siambi,2021™ 40
- 42. Step—III: Application of the forceps: Following rotation, when the right hand is placed on the left side of the pelvis, left blade of the forceps is introduced. When the left hand is used, it is placed on the right side of the pelvis after rotation, as such the right blade is to be introduced first and the left blade is then to be introduced underneath the right blade. While introducing the blades, it is preferable that an assistant fixes the head by suprapubic pressure in a manner of first pelvic grip. As it is a mid-forceps application, axis traction device should be used. 7/5/2021 9:17 AM ©Siambi,2021™ 42
- 43. Difficulties and dangers: The difficulties are due to- (1) Failure to grip the head adequately due to lack of space, (2) Failure to dislodge the head from the impacted position, (3) Inadequate anesthesia, (4) Wrong case selection. Dangers-The chief dangers are accidental slipping of the head above the pelvic brim and prolapse of the cord. It is better to perform cesarean section in such a situation. 7/5/2021 9:17 AM ©Siambi,2021™ 43
- 44. HALF HAND METHOD: In this method, the four fingers and not the thumb are introduced into the vagina. Its advantages over the whole hand method are: (i) less space is required and (ii) less chance to displacement of the head. Steps: The rotation is done only by using the right hand. The four fingers are introduced into the vagina and tangential pressure is applied on the head at the level of diameter of engagement. Thus, the pressure is applied on the side and the parietal eminence of the head. In ROP or ROT positions, the fingers are placed anterior to the head and the pressure is applied by the ulnar border of the hand. In LOP or LOT positions, the fingers are placed posteriorly and the pressure is applied by the radial border of the hand. The force is applied intermittently till the occiput is placed behind the symphysis pubis. 7/5/2021 9:17 AM ©Siambi,2021™ 44