Ergometrine stability in postpartum haemorrhage kits: Does temperature and light matter?

Background: Postpartum haemorrhage (PPH) kits containing uterotonics are used on obstetric units for the timely management of PPH. Visible discolouration of ergometrine and ergometrine-oxytocin injections was observed in PPH kits stored in medical refrigerators on the obstetric unit at our hospital.

Aim: To investigate the stability of ergometrine and ergometrine-oxytocin injections in PPH kits under simulated clinical storage conditions and to determine the potency of ampoules quarantined from PPH kits on our obstetric unit.

Material and methods: Ergometrine and ergometrine-oxytocin injection ampoules were stored exposed to and protected from light at 4°C and room temperature (25°C) for up to three months, and assayed by high-performance liquid chromatography. Stability was based on the time for the ergometrine or oxytocin concentration to fall to 90% of the original concentration (t₉₀ ). The potency of quarantined discoloured ampoules also was determined.

Results: Ergometrine was stable at both temperatures for >6 months, when stored protected from light in simulated clinical conditions. When exposed to light, ergometrine was stable for approximately 4 days at 25°C and 10 days at 4°C. Discoloured ergometrine and ergometrine-oxytocin injection ampoules were found to be <90% of the nominal concentration.

Conclusion: Stability of ergometrine in PPH kits is largely unaffected by temperature fluctuations (at 4°C and 25°C) over 6 months when protected from light. Ergometrine and ergometrine-oxytocin ampoules should be inspected prior to use and any discoloured ampoules discarded.