Malpositions are abnormal positions of the vertex of the fetal head (with the occiput as the reference point) relative to the maternal pelvis. Malpresentations are all presentations of
the fetus other than vertex.
Make a rapid evaluation of the general condition of the woman including vital signs (pulse, blood pressure, respiration, temperature).
Assess fetal condition:
- Listen to the
fetal heart rate immediately after a contraction:
- Count the fetal heart rate for a full minute at least once every 30 minutes during the active phase and every 5 minutes during the second stage;
- If there are
fetal heart rate abnormalities (less than 100 or more than 180 beats per minute), suspect
- If the
membranes have ruptured, note the colour of the draining amniotic fluid:
- Presence of thick meconium indicates the need for close monitoring and possible intervention for management of
- Absence of fluid draining after rupture of the membranes is an indication of reduced volume of amniotic fluid, which may be associated with fetal distress.
Note: Observe the woman closely. Malpresentations increase the risk for uterine rupture because of the potential for obstructed labour.
DETERMINE THE PRESENTING PART
The most common presentation is the vertex of the fetal head. If the
vertex is not the presenting part, see Table
vertex is the presenting part, use landmarks of the fetal skull to determine the position of the fetal head (Fig S-9).
Landmarks of the fetal skull
DETERMINE THE POSITION OF THE FETAL HEAD
Occiput transverse positions
Occiput anterior positions
If the fetal head is well-flexed with occiput anterior or occiput transverse (in early labour),
proceed with delivery.
fetal head is not occiput anterior, identify and manage the malposition
fetal head is not the presenting part or the fetal head is not
well-flexed, identify and manage the malpresentation (Table
TABLE S-11 Diagnosis of malpositions
S-12 Diagnosis of malpresentations
OCCIPUT POSTERIOR POSITIONS
Spontaneous rotation to the anterior position occurs in 90% of cases. Arrested labour may occur when the head does not rotate and/or descend. Delivery may be complicated by
perineal tears or extension of an episiotomy.
- If there are
no signs of obstruction, augment labour with oxytocin.
fetal head is more than 3/5 palpable above the symphysis pubis or the leading bony edge of the head is above -2 station, perform
fetal head is between 1/5 and 3/5 above the symphysis pubis or the leading bony edge of the head is between 0 station and -2 station:
- Delivery by vacuum extraction
the operator is not proficient in symphysiotomy, perform
head is not more than 1/5 above the symphysis pubis or the leading bony edge of the fetal
head is at 0 station, deliver by vacuum extraction or
In brow presentation, engagement is usually impossible and arrested labour is common. Spontaneous conversion to either vertex presentation or face presentation can rarely occur,
particularly when the fetus is small or when there is fetal death with maceration. It is unusual for spontaneous conversion to occur with an average-sized live fetus once the
membranes have ruptured.
cervix is not fully dilated, deliver by caesarean section;
cervix is fully dilated:
- Deliver by craniotomy;
the operator is not proficient in craniotomy, deliver by
Do not deliver brow presentation by vacuum extraction, outlet forceps or symphysiotomy.
The chin serves as the reference point in describing the position of the head. It is necessary to distinguish only chin-anterior positions in which the chin is anterior in relation to the
maternal pelvis (Fig S-24 A) from chin-posterior positions (Fig S-24 B).
Prolonged labour is common. Descent and delivery of the head by flexion may occur in the chin-anterior position. In the chin-posterior position, however, the fully extended head is
blocked by the sacrum. This prevents descent and labour is arrested.
- Allow to proceed with normal childbirth;
- If there is
slow progress and no sign of obstruction (Table
S-10), augment labour with oxytocin;
descent is unsatisfactory, deliver by forceps.
If the cervix is fully dilated, deliver by caesarean section.
If the cervix is
not fully dilated, monitor descent, rotation and progress. If there are
signs of obstruction, deliver by caesarean section.
fetus is dead:
- Deliver by craniotomy;
- If the operator is not proficient in craniotomy, deliver by caesarean section.
Do not perform vacuum extraction for face presentation.
Spontaneous delivery can occur only when the fetus is very small or dead and macerated. Arrested labour occurs in the expulsive stage.
- Assist the woman to assume the knee-chest position (Fig S-25);
- Push the arm above the pelvic brim and hold it there until a contraction pushes the head into the pelvis.
- Proceed with management for normal childbirth.
Prolonged labour with breech presentation is an indication for urgent caesarean section. Failure of labour to progress must be considered a sign of possible disproportion
The frequency of breech presentation is high in preterm labour.
Ideally, every breech delivery should take place in a hospital with surgical capability.
- breech presentation is present at or after 37 weeks (before 37 weeks, a successful version is more likely to spontaneously revert back to breech presentation);
- vaginal delivery is possible;
- membranes are intact and amniotic fluid is adequate;
- there are no complications (e.g. fetal growth restriction, uterine bleeding, previous caesarean delivery, fetal abnormalities, twin pregnancy, hypertension, fetal death).
VAGINAL BREECH DELIVERY
- complete (Fig
S-20) or frank breech (Fig
- adequate clinical pelvimetry;
- fetus is not too large;
- no previous caesarean section for cephalopelvic disproportion;
- flexed head.
Note: Do not rupture the membranes.
cord prolapses and delivery is not imminent, deliver by caesarean section.
If there are
fetal heart rate abnormalities (less than 100 or more than 180 beats per minute) or
prolonged labour, deliver by caesarean section.
Note: Meconium is common with breech labour and is not a sign of fetal distress if the fetal heart rate is normal.
The woman should not push until the cervix is fully dilated. Full dilatation should be confirmed by vaginal examination.
CAESAREAN SECTION FOR BREECH PRESENTATION
- double footling breech;
- small or malformed pelvis;
- very large fetus;
- previous caesarean section for cephalopelvic disproportion;
- hyperextended or deflexed head.
Note: Elective caesarean section does not improve the outcome in preterm breech delivery.
Fetal complications of breech presentation include:
birth trauma as a result of extended arm or head, incomplete dilatation of the cervix or cephalopelvic disproportion;
asphyxia from cord prolapse, cord compression, placental detachment or arrested head;
damage to abdominal organs;
TRANSVERSE LIE AND SHOULDER PRESENTATION
- If external version is successful, proceed with normal childbirth;
external version fails or is not advisable, deliver by caesarean section (page P-43).
Note: Ruptured uterus may occur if the woman is left unattended
In modern practice, persistent transverse lie in labour is delivered by caesarean section whether the fetus is alive or dead.
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