This is the ValueSet that contains all the codes in Gestational Age (LOINC) (http://hl7.eu/fhir/eps/ValueSet/gestational-age-loinc) and Gestational Age (LOINC) (http://hl7.eu/fhir/eps/ValueSet/gestational-age-loinc). E.g. what you have to deal with if you get resources containing codes in either of them