Preeclampsia is a hypertensive disorder of pregnancy that is characterized by new-onset hypertension with proteinuria presenting after 20 weeks of gestation, and depending on mild or severe forms may initially present with severe headache, visual disturbances, and hyperreflexia. The disease is Monarch Disease Ontology id MONDO_0005081 (preeclampsia). Also known as: gestational hypertension, hypertension induced by pregnancy, pre-eclampsia, pre-eclamptic toxaemia, pre-eclamptic toxemia, preeclampsia/eclampsia, pregnancy associated hypertension, pregnancy toxaemia.