Randomized comparison of different cardiotoxicity of carbetocin and oxytocin.

Carbetocin has been in clinical use in EU for some years and the efficacy is documented in several RCTs. Circulatory adverse events leading to death has been reported after intravenous injection of oxytocin. Some studies indicate that oxytocin may lead to dose dependent ischemic ECG changes, prolongation of QT time and liberation of biomarkers of myocardial cell death. Previously we have demonstrated comparable vasodilatory effects of oxytocin and carbetocin. There is no clinical study comparing the specific myocardial effects of oxytocin with carbetocin. It may have great impact on the choice of standard medication if the cardiotoxicity of carbetocin is lower compared with oxytocin. The study of potential cardiotoxicity has to be performed in healthy women. Knowing that millions of laboring women have had uneventful injections of oxytocin and carbetocin after delivery, there is probably no reason to fear long lasting negative effects of either drug. If there are differences in cardiotoxicity, this new information should be taken into consideration when planning delivery in pregnant women with heart disease.

The aims of this study are to compare 0h (before C-section), 4h, 12h, 24h, and 48h plasma concentrations of Troponin I, Troponin T, proBNP, CK, and other relevant myocardial markers in elective healthy C-section patients randomized to oxytocin 2.5 U or carbetocin 100 µg, 1 minute injection immediately after delivery.

Inclusion Criteria:

1. Healthy pregnant women age 18 to 50
2. Singleton pregnancy at gestational age 36 weeks or more
3. Able to read and understand Norwegian.

Exclusion Criteria:

1. Patients with placenta pathology such as praevia, acreta, pre-eclampsia
2. Patients with bleeding disorders including vonWillebrand disease type I.
3. Known intolerance to one of the two drugs.
4. Patients with prolonged QT-time or other serious cardiac diseases.
5. Liver or kidney failure.
6. Epilepsy.
7. Any medical reason why, in the opinion of the investigator, the patient should not participate

Participant data will be analyzed in the Research Group only