Hypertonic Uterine Dysfunction

Hypertonic uterine dysfunction is labour with frequent painful contractions and a raised resting tone of the uterus, in which the contractions are strong but cause little or no cervical dilatation. It usually occurs in the latent phase, with pain out of proportion to the progress, and is more common in first labours with an unripe cervix or malposition. It matters because it exhausts the woman, reduces placental blood flow and can be mistaken for abruption or uterine rupture, and oxytocin makes it worse.

• Risk factors: first labour, unfavourable cervix, occiput posterior position, anxiety, abruption, oxytocin or misoprostol excess.
• The uterus does not fully relax between contractions.
• It is treated with rest and analgesia, not oxytocin.

Women have severe, frequent, painful contractions with little cervical change, backache and distress. The uterus is firm between contractions and tender, and fetal parts are hard to feel.

• Contractions every 1 to 2 minutes with raised resting tone.
• Little or no cervical dilatation despite hours of pain.
• Differential diagnosis: placental abruption, uterine rupture, incoordinate action, uterine hyperstimulation from drugs, chorioamnionitis, urinary infection, false labour.
• Complications: maternal exhaustion, fetal hypoxia and heart rate abnormality, abruption, prolonged labour, caesarean section, ketosis.

The diagnosis is clinical, with exclusion of abruption, rupture and drug effect.

• Palpation: resting tone between contractions, tenderness, frequency, and duration; tocography with baseline tone where available.
• Vaginal bleeding, uterine tenderness and fetal heart changes (suggesting abruption); scar tenderness and loss of contractions (suggesting rupture).
• Cardiotocography; maternal pulse, blood pressure, temperature, urine ketones; drug history (oxytocin, misoprostol).
• Ultrasound for retroplacental clot, position and fetal wellbeing.

The principle is to stop uterotonic drugs, give analgesia and rest, and to deliver by caesarean section for abruption or fetal compromise.

• Supportive: stop oxytocin and remove misoprostol if present; left lateral position; Ringer's lactate 1 litre IV over 1 to 2 hours; empty the bladder; reassurance and one to one support; continuous cardiotocography; warm bath or shower.
• Pharmacological: morphine 10 mg IM plus promethazine 25 mg IM for therapeutic rest (6 to 12 hours of sleep); hyoscine butylbromide 20 mg IV or IM repeated once after 30 minutes if needed (maximum 100 mg in 24 hours); terbutaline 0.25 mg subcutaneous once for severe tachysystole with fetal distress; epidural analgesia; oxytocin only after rest, if contractions have normalised and are still ineffective, started at 2 mU/minute and doubled every 30 minutes to a maximum of 32 mU/minute; cefazolin 2 g IV before caesarean section; oxytocin 10 IU IM after birth, then 20 IU in 1 litre at 125 mL per hour for 4 hours.
• Procedures: caesarean section for abruption, uterine rupture, abnormal fetal heart rate that does not recover within 30 minutes of treatment, or no progress after rest.
• Special groups: suspected abruption or scar tenderness needs urgent caesarean section rather than analgesia; a uterine scar with tachysystole needs immediate review for rupture.
• Red flags: vaginal bleeding, constant pain, fetal bradycardia, scar tenderness, maternal tachycardia, shock.
• Follow-up: reassess contractions and cervix after rest; maternal temperature 4-hourly; observe the newborn for 24 hours for respiratory depression after opioids given within 4 hours of birth; review at 6 weeks.