Physical and psychological disorders in the mother that occur during pregnancy, childbirth, and the postpartum period. These include both pre-existing and gestational maternal health conditions that may result in adverse pregnancy outcomes. The Maternal Conditions Ontology builds on the work done for a handful of existing ontologies, including the Human Phenotype Ontology (HPO) and NCI Thesaurus (NCIT), and was further developed by PAT External Scientific Panel Members and contributions from other subject matter experts.