description: This profile sets minimum expectations for an Observation resource to record, search, and fetch observations that represent the date of a patient’s last known menstrual period at a point in time with standard coding and value. It is based on the core FHIR [Observation](http://hl7.org/fhir/R4/observation.html) resource and identifies the *additional* mandatory core elements, extensions, vocabularies and value sets that **SHALL** be present in the Observation resource when conforming to this profile. It provides the floor for standards development for specific uses cases in an Australian context.
package_name: hl7.fhir.au.core
derivation: constraint
name: AUCoreLastMenstrualPeriod
type: Observation
elements:
  encounter:
    type: Reference
    mustSupport: true
    refers: ['http://hl7.org.au/fhir/core/StructureDefinition/au-core-encounter']
    index: 7
  value:
    mustSupport: true
    choices: [valueDateTime]
    index: 13
  valueDateTime: {type: dateTime, mustSupport: true, choiceOf: value, index: 14}
  effectiveDateTime:
    constraint:
      au-core-obs-01: {human: Date shall be at least to day, source: 'http://hl7.org.au/fhir/core/StructureDefinition/au-core-lastmenstrualperiod', severity: error, expression: $this is DateTime implies $this.toString().length() >= 10}
    short: Date, and optionally time, the observation was performed
    type: dateTime
    mustSupport: true
    choiceOf: effective
    index: 10
  status:
    pattern: {type: Code, value: final}
    mustSupport: true
    index: 0
  effective:
    constraint:
      au-core-obs-01: {human: Date shall be at least to day, source: 'http://hl7.org.au/fhir/core/StructureDefinition/au-core-lastmenstrualperiod', severity: error, expression: $this is DateTime implies $this.toString().length() >= 10}
    short: Date, and optionally time, the observation was performed
    mustSupport: true
    choices: [effectiveDateTime]
    index: 9
  code:
    mustSupport: true
    pattern:
      type: CodeableConcept
      value:
        coding:
        - {code: '21840007', system: 'http://snomed.info/sct'}
    index: 1
    elements:
      coding:
        index: 2
        slicing:
          rules: open
          discriminator:
          - {path: code, type: value}
          - {path: system, type: value}
          min: null
          slices:
            loincLastMenstrualPeriod:
              match: {code: 8665-2, system: 'http://loinc.org'}
              schema:
                short: LOINC Last Menstrual Period
                index: 3
                elements:
                  system:
                    pattern: {type: Uri, value: 'http://loinc.org'}
                    index: 4
                  code:
                    pattern: {type: Code, value: 8665-2}
                    index: 5
                required: [system, code]
  subject:
    type: Reference
    mustSupport: true
    refers: ['http://hl7.org.au/fhir/core/StructureDefinition/au-core-patient']
    index: 6
  performer:
    type: Reference
    mustSupport: true
    refers: ['http://hl7.org.au/fhir/core/StructureDefinition/au-core-organization', 'http://hl7.org.au/fhir/core/StructureDefinition/au-core-patient', 'http://hl7.org.au/fhir/core/StructureDefinition/au-core-practitioner', 'http://hl7.org.au/fhir/core/StructureDefinition/au-core-practitionerrole', 'http://hl7.org.au/fhir/core/StructureDefinition/au-core-relatedperson']
    index: 11
  dataAbsentReason: {mustSupport: true, index: 15}
package_version: 0.1.0-draft
class: profile
kind: resource
url: http://hl7.org.au/fhir/core/StructureDefinition/au-core-lastmenstrualperiod
base: http://hl7.org/fhir/StructureDefinition/Observation
version: 0.1.0-draft
required: [effectiveDateTime, subject, effective]