| |
Slow progress of labour associated with prolonged active
phase
The diagnosis of a prolonged latent phase is made retrospectively:
| :: |
When
contractions cease, diagnose as false labour |
| :: |
When
contractions become regular and dilatation progresses
beyond 4 cm, diagnose as latent phase. |
Mistaking false labour for the latent phase leads to unnecessary
induction and unnecessary caesarean section.
The latent phase is prolonged when the cervical dilatation
remains less than 4 cm after 8 hours. If a woman has been
in the latent phase for more than 8 hours, reassess the situation:
| :: |
If
there has been no change in cervical effacement or dilatation
and there is no fetal distress, review the diagnosis
of labour; the woman may not be in labour |
| :: |
If
there has been a change in cervical effacement and dilatation,
augment contractions with oxytocin. Artificial rupture
of membranes is recommended along with or before augmentation
of labour with oxytocin. In areas of high HIV prevalence,
however, if elective caesarean section is not the preferred
option, try to leave the membranes intact for as long
as possible to reduce the risk of transmission of HIV. |
Reassess every 4 hours:
| :: |
If
the woman has not entered the active phase within 8 hours,
consider delivery by caesarean section, but be sure the
patient is not in false labour |
| :: |
If
membranes are already spontaneously ruptured, induce
or augment labour without delay |
| :: |
In
areas of high Group B streptococcal prevalence, give
antibiotic prophylaxis starting at 12 hours after rupture
of the membranes to help reduce Group B streptococcus
infection in the neonate |
| :: |
If
there is any evidence of amnionitis, augment labour immediately
and treat with antibiotics. |
Slow progress of labour associated with Prolonged Active
Phase
During active labour, dilatation usually progresses at least
1 cm per hour. Any rate of dilatation slower than this indicates
a slow active phase. If the slow active phase is neglected,
it can lead to a prolonged active phase. Slow progress of
labour in the active phase of labour may be due to one or
more of the following causes:
| :: |
Inefficient
uterine contractions |
| :: |
Malpresentations
and malpositions: e.g. occipito-posterior |
| :: |
Disproportion
between the size of the fetus and the pelvis. |
These
causes may be interrelated. When the rate of dilatation in
the active phase is slower than 1 cm per hour, reassess the
mother for poor contractions or malpresentation:
| :: |
If
there is evidence of obstruction, perform a caesarean
section |
| :: |
If
there is no evidence of obstruction, augment labour with
amniotomy and oxytocin. |
General
methods of labour support may improve contractions and accelerate
progress:
| :: |
Provide
emotional support and encouragement |
| :: |
Encourage
walking, sitting and changes of position |
| :: |
Give
abundant fluids either by mouth or IV |
| :: |
Encourage
urination |
| :: |
Catheterize
only as a last resort. |
Reassess
progress by vaginal examination after 2 hours of good contractions:
| :: |
If
there is no progress between examinations, deliver by
caesarean section |
| :: |
If
there is progress, continue oxytocin and re-examine after
2 hours. |
Continue
to follow progress carefully.
Inefficient, poor uterine contractions are less common in
a multigravida, so make every effort to rule out disproportion
before augmenting with oxytocin.
In the active phase of labour, plotting of cervical dilatation
will normally remain on, or to the left of the alert line
on the partograph. The action line is 4 hours to the right
of the alert line. If a woman’s labour reaches this
line, you will need to make a decision about
the cause of the slow progress and take appropriate action.
Slow progress of labour associated with Prolonged Expulsive
Phase
The effective force during delivery of the fetus comes
from uterine contractions. Spontaneous maternal “pushing” should
be permitted, but the practice of encouraging
breath-holding and prolonged effort should be abandoned.
Prolongation of the expulsive phase may also occur
for the same reasons as prolongation of the active
phase. If malpresentation and obvious obstruction
have been excluded, failure of descent in the expulsive
stage should also be treated by oxytocin infusion
unless contraindicated. If there is no descent even
after augmentation with oxytocin, consider assisted
delivery.
Assisted vaginal delivery by forceps or ventouse is indicated
if the head is engaged (not more than 1/5 of the head is
palpable above the pelvic brim) or if the leading bony edge
of the fetal head is at 1 cm or more below the level of the
ischial spines by vaginal examination.
Caesarean delivery is the preferred option if the head is
at a higher level.
Slow progress of Labour associated with Malpositions and
Malpresentations
Occipito-posterior positions
Spontaneous rotation to the anterior position occurs in 90%
of cases. Spontaneous delivery in the posterior position
may occur, but labour may be complicated by prolonged first
and second stages. Perineal tears and extensions of an episiotomy
may complicate delivery.
Arrested labour
Arrested labour may occur when rotation and/or descent of
the head does not occur:
| :: |
Ensure
adequate hydration |
| :: |
Check
maternal and fetal condition |
| |
If
there is fetal distress, consider delivery by caesarean
section if quick and easy vaginal delivery is not possible |
| :: |
If
there is still no descent after a trial of labour and
the head is engaged and at 1 cm or more below the ischial
spines, deliver by forceps or ventouse |
| :: |
If
the head is >1/5 palpable on abdominal examination,
deliver by caesarean section |
| :: |
If
there is evidence of obstruction or fetal distress at
any stage, deliver by caesarean section.
|
Brow
presentation
Spontaneous conversion to either vertex or face presentation
may occur, particularly when the fetus is small or when there
is fetal death with maceration. It is unusual for spontaneous
conversion to occur in an average sized live baby once membranes
have ruptured. Arrested labour is usual.
When the fetus is living:
| :: |
Deliver
by caesarean section. |
When the fetus is dead:
| :: |
If
dilatation is incomplete, deliver by caesarean section |
| :: |
If
dilatation is complete, perform craniotomy or caesarean
section. |
Do not deliver brow presentation by vacuum extraction, forceps
or symphysiotomy.
Face presentation
Prolonged labour is common with face presentation:
| :: |
In
the chin-anterior position, descent and delivery of the
head by flexion may occur |
| :: |
In
the chin-posterior position, the fully extended head
is blocked by the sacrum from descent and arrest of labour
occurs. |
Face presentation, chin anterior, can usually be delivered
vaginally. Chin posterior can rarely be delivered vaginally.
| :: |
Ensure
adequate hydration |
| :: |
Check
maternal and fetal condition |
| |
If
there is fetal distress, consider delivery by caesarean
section if quick and easy vaginal delivery is not possible |
| :: |
If
the cervix is not fully dilated and it is a chin-anterior
position and there is no evidence of obstruction, augment
with oxytocin; review progress as with vertex presentation |
| :: |
If
it is a chin-posterior position or there is evidence
of obstruction, deliver by caesarean section |
| :: |
If
the cervix is fully dilated and it is a chin anterior
and there is no evidence of obstruction, augment with
oxytocin; if descent is satisfactory, deliver by forceps |
| :: |
If
descent is unsatisfactory, deliver by caesarean section |
| :: |
If
the fetus is dead, perform craniotomy or caesarean section. |
Do not perform vacuum extraction for face presentation.
Compound presentation (arm prolapsed alongside presenting
part)
Spontaneous
delivery can occur only when the fetus is very small or dead
and macerated. Arrested labour in the expulsive stage is
the rule. Replacement of the prolapsed arm is sometimes possible.
| :: |
Place
the patient in the knee-chest position. Push the arm
above the pelvic brim and hold it there until a contraction
pushes the head into the pelvis. |
| :: |
Cord
prolapse is a risk of this procedure, so be prepared
to perform a caesarean section. |
Breech presentation
Prolonged labour is an indication for urgent caesarean section
in breech presentation (Figures 11.6,
11.7, 11.8). Failure
of labour to progress is a sign of possible disproportion.
Transverse lie
Caesarean section is the management of
choice, whether the fetus is alive or dead (Figure
11.9).
Delivery through a transverse uterine incision may be difficult,
especially if the arm is prolapsed or the fetus is back-down,
and often results in extension of the incision with laceration
of a uterine artery.
|
|
|
