Efficacy of Bicarbonate on the Risk of Assisted Delivery in Nulliparous Women With Prolonged Labour

Inclusion Criteria: * Age ≥18 years. * Danish or English speaking. * Cephalic presentation. * Gestational age ≥34+0 - \<42+0 (days +weeks) at onset of labour. * Normal foetal heart rate pattern in the 20 minutes prior to inclusion. * Spontaneous onset of labour or non-medical induced labour (balloon catheter and/or artificial rupture of membranes). * Active first stage of labour confirmed, according to Danish national guidelines: Cervical dilatation at ≥4 - \<10 cm with regular painful contractions. * Prolonged labour diagnosed, according to Danish national guidelines: Cervical dilatation progresses at less than 2 cm over a 4-hour period. Exclusion Criteria: * Clinical suspicion of infection (2 confirmed temperatures ≥38.5°C with epidural, ≥38 °C without epidural, or broad-spectrum antibiotics initiated) * Significant medical comorbidity in the form of renal or heart condition, assessed case-by-case basis. * Serious obstetric complication * Known allergy or intolerance to sodium bicarbonate. * Ingestion of sodium bicarbonate in active labour prior to inclusion. * Current treatment with following medicines: Gabpabpentin, Tetracycline, Ketoconazole (NB! These medications are already generally advised contradicted against induring pregnancy)