PI4 - A Trial Assessing Metformin to Prolong Gestation in Preterm Preeclampsia

Inclusion Criteria: * A diagnosis of preeclampsia (defined as hypertension in combination with significant proteinuria (albumin/creatinine ratio \>8 mg/mmol, protein/creatinine ratio\>30 mg/mmol or \>2+ protein on a urinary dipstick) has been made by the attending clinician * The managing clinicians have made the assessment to proceed with expectant management. * The subject has given written consent to participate in the study. * The woman must be 18 years of age or older * The gestational age is between 22+0 weeks to 33+6 weeks with a viable fetus * The woman carries a singleton pregnancy Exclusion Criteria: * Contraindications to treatment with metformin as outlined in SmPC * Contraindications for expectant management of preeclampsia such as an immediate indication for delivery according to SFOG guidelines for preeclampsia (https://www.sfog.se/media/338533/pe-riktlinje-230214.pdf). * Type 1 Diabetes Mellitus * Current use of metformin * Known or suspected allergies against metformin * Reluctance or language difficulties that result in difficulty understanding the meaning of study participation * Unable to understand the informed consent process * Previous participation in the study * Established fetal compromise that necessitates imminent delivery (including planned delivery after 48 hours of corticosteroid treatment). This will be decided by the clinical team before expectant management is offered to the patient. * Suspicion of a major known fetal anomaly or malformation. * Renal disease or dysfunction, suggested by a creatinine level greater than or equal to 125 µmol/L or rapidly declining renal function * Known acute or chronic metabolic acidosis, including diabetic ketoacidosis * Not suitable for inclusion by the opinion of the investigator