disorder of menstrual cycle length oligomenorrhea http://purl.bioontology.org/ontology/MEDDRA/10030295 http://purl.bioontology.org/ontology/MESH/D009839 http://purl.bioontology.org/ontology/SNOMEDCT/52073004 http://purl.obolibrary.org/obo/HP_0000876 http://purl.obolibrary.org/obo/NCIT_C113341 https://en.wikipedia.org/wiki/Oligomenorrhea https://www.wikidata.org/wiki/Q1970295 Abnormally infrequent menstruation. Infrequent menses (less than 6 per year or more than 35 days between cycles).