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Authors: Janet Medforth,Sue Battersby,Maggie Evans,Beverley Marsh,Angela Walker

Oxford Handbook of Midwifery (73 page)

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Greater risk of instrumental delivery
Difficult or traumatic delivery
Infection
Possible fetal hypoxia
Intracranial haemorrhage.
Outcomes
Long rotation of the occiput
In two-thirds of cases, following engagement the head flexes.
When the occiput meets the resistance of the pelvic floor it makes a long rotation forwards through three-eighths of a circle.
The fetus is then born in the occcipito-anterior position.
Deflexed head
In one-third of cases, flexion of the head remains deficient and the mecha- nism of internal rotation is affected by the following:
Deep transverse arrest
: an attempt at long rotation fails, the head being arrested with its long diameter between the ischial spines. Instrumental rotation with forceps or ventouse is required to complete the delivery. Alternatively an LSCS may be performed.
Persistent occipito-posterior
: the sinciput lying lower than the occiput is rotated one-eighth of a circle towards the symphysis pubis and the occiput turns to the hollow of the sacrum. Delay in the second stage
occurs, but with good contractions the head advances, the root of the nose escapes under the pubic arch and the head is born in the face- to-pubes position. When contractions are less effective, no advance occurs and instrumental delivery is required.
Midwifery care and management
The first stage is long and tedious, and often accompanied by severe backache. Give continuous explanation, empathy, and support.
Mobility and an upright position encourage rotation and descent.
All fours or squatting may assist rotation of the head.
Maternal comfort, hydration, and prevention of infection are important.
Encourage the woman to empty the bladder regularly, as a full bladder may add to discomfort and delay progress.
Deal promptly once delay and fetal and/or maternal distress are recognized. Avoid language which may demoralize the woman, e.g. ‘failure to progress’.
Pain relief requirements may be increased.
Consider the use of epidural analgesia carefully, as its effects may contribute to poor flexion of the fetus, lack of descent, and failure of the rotational mechanism.
However, if an instrumental delivery is anticipated then epidural analgesia is the preferred method of pain relief.
The second stage is characterized by considerable dilation of the anus, while the fetal head may not be visible.
The squatting position may increase the sagittal diameter of the pelvic outlet, which may aid delivery.
Perineal trauma is common. Look for signs of central rupture.
Occasionally episiotomy may be needed to expedite the delivery.
CHAPTER 17
Management of malpositions
316‌‌
Face presentation
When the attitude of the head is one of complete extension, the occiput of the fetus will be in contact with its spine and the face will present. Most cases develop in labour from occipito-posterior positions (secondary face
presentation). Rarely, face presentation is apparent before labour and may
be associated with congenital abnormality (primary face presentation).
Causes
- The uterus is tilted sideways (anterior obliquity)
- Contracted pelvis
- Tight or entangled cord
- Polyhydramnios
- Congenital abnormality (e.g. anencephaly)
- Multiple pregnancy.
  Diagnosis
- Antenatal diagnosis is unlikely as the presentation usually develops in labour.
- On palpation: if the mentum is anterior, the presentation may not be detected. If the mentum is posterior, a deep groove may be felt between the occiput and the fetal back.
- On vaginal examination:
  - The presenting part is high and irregular
  - The orbital ridges, eyes, nose, and mouth are palpable
  - There may be confusion between the mouth and anus; differential signs are: open, hard gums, ridged palate, and the fetus may suck the examining finger
  - To determine the position, the mentum is located
  - Vaginal examinations should be undertaken with care so as not to injure or infect the eyes.
    Course and outcomes of labour
- Prolonged labour
- With a mentoanterior position: spontaneous delivery.
- With a mentoposterior position: following rotation of the mentum to the anterior, a spontaneous delivery is possible.
- Persistent mentoposterior: the chin is in the hollow of the sacrum, so no further mechanism takes place. Instrumental assisted birth or LSCS is the outcome.
  Management of labour and delivery
- Labour is often prolonged, the presenting part is ill fitting, so there is slow progress.
- Maternal comfort and support are important.
- Communicate and empathize, as the woman may become discouraged and anxious about her abilities.
- Prior to delivery explain the possible facial bruising to the parents
- Recognize delay or complications at an early stage.
- Avoid the use of a scalp electrode.
- Avoid the use of IV oxytocin.
  FACE PRESENTATION
  317
Birth may be facilitated by supporting the extended fetal position and applying gentle pressure on the sinciput until the mentum escapes.
An episiotomy may be indicated, before the occiput sweeps the perineum.
Complications
Obstructed labour, as the face is resistant to moulding
Early rupture of the membranes
Cord prolapse
Facial bruising and oedema
Cerebral haemorrhage
Perineal lacerations and perineal trauma.
CHAPTER 17
Management of malpositions
318‌‌
Brow presentation
When the attitude of the head is one of partial extension, the frontal bone presents. Brow presentation is less common than face presentation. occurring once in about 1000 births. The causes are the same as those for
face presentation.
Diagnosis
- On abdominal palpation the presenting part is high and appears unduly large. A groove may be felt between the occiput and the back.
- On vaginal examination there may be difficulty in reaching the presenting part.
- If the brow is detected, the anterior fontanelle may be felt to one side with the orbital ridges or root of the nose felt on the other side.
- The presenting diameter is the mentovertical—13.5cm.
  Management
- The midwife should call the obstetrician.
- Vaginal birth is rare.
- Usually LSCS for obstructed labour.
- Occasionally may convert to a face presentation.
- Complications are the same as those of face presentation.
  SHOULDER PRESENTATION
  319‌‌
  Shoulder presentation
  A non-longitudinal lie may be transverse or oblique, both can result in a shoulder presentation if not corrected.
  Causes