Chapter 14 Abnormal labour
ABNORMAL UTERINE ACTIVITY
False labour (spurious labour)
Management
• Assess the woman to establish whether or not she is in labour. Observe contraction strength and frequency; check cervix on admission and review 1–2 hours later. If the cervix is <4 cm and there is no dilatation over the observation period, she is either in the latent phase of labour or not in labour. Assess fetal wellbeing using a 20 minute cardiotocograph (CTG) (this is not a requirement of the National Institute of Health and Clinical Excellence). If deemed not in active labour and fetus is satisfactory, she may go to the ward to await events. If appropriate some women may even go home.
• The presence of risk factors, i.e. abnormalities in the pregnancy or a non-reassuring CTG, indicate the need for close surveillance with consideration to augment or induce labour.
Precipitate labour and delivery
• When there is little resistance to delivery. With an effaced cervix 3 cm or more dilated and the presenting part engaged and well applied, little harm is likely if labour is properly conducted in an appropriate environment. Women with a history of precipitate labours should be admitted around 38 weeks for induction of labour to control the situation.
• Rapid labour may follow sensitivity to or excessive use of oxytocics. The fetus is pushed rapidly through the birth canal by strong frequent uterine contractions. Fetal hypoxia and trauma together with soft tissue damage of the birth canal are likely. This should not happen in well-conducted labours.
Management
• Anticipate the situation from the obstetric history. Women must be carefully selected for oxytocin stimulation. This is particularly important in grand multipara or in women with a history of short labours.
• The maternal and fetal conditions must be closely monitored. A midwife must be in attendance to supervise labour.
Sudden cessation of labour
Management
• The globular outline of the uterus is lost, fetal parts may be readily palpable, the fetal heart sounds may be absent, lie may not be longitudinal.
• If repair of the uterus is not possible proceed to hysterectomy. There is a place for subtotal hysterectomy in this situation.
Box 14.1 gives more information on uterine rupture.
Box 14.1 Uterine rupture
Associations
• Previous uterine damage or surgery, e.g. myomectomy that encroached into the uterine cavity, hysterotomy and perforations.
• Caesarean sections, particularly classic sections (may rupture before onset of labour). Multiple sections or sections with inadvertent extension or need for an inverted T incision (Chapter 17). History of infection may mean poor healing and a weaker scar.
• Oxytocic usage. The very unfavourable cervix, previous lower segment caesarean section and oxytocic augmentation in multiparous women require careful assessment and close observation.
• Prostaglandin pessaries should be used with caution when priming a cervix in the presence of a previous caesarean scar.
PROLONGED LABOUR
Abnormal contractions (powers)
Frequent strong contractions (hypertonic contractions)
These can follow the inappropriate use of oxytocics. Prolonged labour associated with strong contractions is seen principally in multiparous mothers with disproportion. The practised uterus mounts an increased effort to overcome the obstruction. The resultant frequent strong contractions and increased uterine tone result in both maternal and fetal distress. If allowed to continue tetanic uterine activity can occur. A retraction ring denoting the junction between the strong contracting upper uterine segment and the overstretched lower segment is observed as a late sign of imminent uterine rupture.
