Query: When was my last prenatal visit?, FHIR Resource: {'resourceType': 'AllergyIntolerance', 'clinicalStatus': {'coding': [{'system': 'http://terminology.hl7.org/CodeSystem/allergyintolerance-clinical', 'code': 'active'}]}, 'verificationStatus': {'coding': [{'system': 'http://terminology.hl7.org/CodeSystem/allergyintolerance-verification', 'code': 'confirmed'}]}, 'type': 'allergy', 'category': ['food'], 'code': {'coding': [{'system': 'http://snomed.info/sct', 'code': '102263004', 'display': 'Eggs (edible) (substance)'}], 'text': 'Eggs (edible) (substance)'}, 'patient': {'reference': 'urn:uuid:d02baa31-9644-9ee3-cb2c-4f9fb487bd24'}, 'onsetDateTime': None}