This guideline has been based on the Victorian Standard for Induction of Labour (IOL) - Management of Excessive Uterine Activity and Clinical Practice Guideline prepared by the Maternity Newborn Clinical Network which has the objective of providing Maternity Service providers in Victoria with an agreed Standard of Care based on the best currently available evidence.

Early recognition and management of excessive uterine activity with prompt and appropriate interventions to reduce maternal and perinatal morbidity and mortality.

RANZCOG Royal Australian and New Zealand College of Obstetricians and Gynaecologists

Augmentation: is an intervention that increases the frequency, duration and intensity of contractions after the onset of spontaneous labour.

Cervical ripening: is the process of softening and effacing the cervix in preparation for labour

Induction of labour (IOL): is an intervention designed to artificially initiate cervical ripening and uterine contractions resulting in progressive effacement and dilation of the cervix and birth of the baby.

Excessive uterine activity is defined as:
- Tachysystole - more than five active labour contractions in ten minutes, without fetal heart rate abnormalities
OR
- Uterine hypertonus - contractions lasting longer than two minutes in duration or contractions occurring within 60 seconds of each other, without fetal heart rate abnormalities.

Uterine hyperstimulation is defined as:
- Either Tachysystole or Uterine hypertonus with fetal heart rate abnormalities.

Excessive uterine activity may occur with or without Fetal Heart Rate changes and is defined as:

• 5 or more contractions in 10 minutes over a 30 min period or
  
• Contractions lasting more than 2 minutes in duration or
  
• Contractions of normal duration occurring within 60 seconds of each other

• Early recognition is essential as excessive uterine activity causes poor uterine placental perfusion leading to a decrease in fetal oxygenation and eventually fetal compromise.

• When assessing for excessive uterine activity consideration should be given to both the duration and frequency of the contractions. Contractions normally vary in duration from 30-60 seconds during the first stage of labour, to 90 seconds during the second stage of labour. The average well grown fetus at term requires 60-90 seconds of uterine rest between active labour contractions to maintain adequate oxygenation.

• Excessive uterine activity is frequently associated with oxytocin infusions, therefore judicious use of oxytocin and continuous cardiotocograph (CTG) is required whenever an oxytocin infusion is being administered (refer CPP0141 Oxytocin (Syntocinon) - Induction and augmentation of labour and CPP0356 Oxytocin (Syntocinon) Infusion).

• Where excessive uterine activity occurs naturally a CTG is also required to ensure early recognition of fetal heart rate (FHR) changes.

• Adverse effects on the fetus may be avoided by minimising periods of excessive uterine activity, and administering treatment in a timely manner rather than waiting until the FHR becomes abnormal

Management of Excessive Uterine Activity is as per:

RANZCOG - refer to link in reference section

Appendix 1 Flowchart - Management of Excessive Uterine Activity