Alexa Jo Duling Williams, MD

Primary specialty

Obstetrics & Gynecology PhysicianTaxonomy code 207V00000X

License

2021013439 Issued in MO

Practice address

1101 Highway K
O Fallon, MO 63366-8431

Phone

(636) 379-6363

NPI assigned

Jun 15, 2017

Sex

Female

Sole proprietor

Yes

Registry information is reported by the provider to CMS and is not verified. About this source

Specialties & licenses 2

Addresses

Electronic endpoints 2

Medicare fee-for-service enrollment

Enrolled in MO

Eligible to order & refer

• Part B services: Yes
• Medical equipment: Yes
• Home health: Yes
• Power mobility devices: Yes
• Hospice: Yes

Green means eligible to order or refer.

Enrollment records 1

Specialty

Obstetrics/Gynecology

Education

University of Arizona College of Medicine, 2017

Medicare assignment

Accepts the Medicare-approved amount as payment in full

Group practices

SSM Medical Group IncGroup PAC ID 6608776299, 565 clinicians

Practice addresses (Care Compare)

Hospital & facility affiliations

• SSM St Joseph Health Center Hospital, Saint Charles, MO, CCN 260005

Medicare enrollment (NPD)

Enrolled

Credentials

Doctor of Medicine

State licenses

Practice roles

Locations

Interoperability endpoints

• Direct secure messaging: awilliams558665@direct-ehr-ssmhc.com

Organizations this provider is connected to: Medicare benefit reassignments (the organization bills Medicare for this provider’s services), Care Compare group memberships and National Provider Directory roles.

• SSM Medical Group, Inc.

  • Multi-Specialty Clinic/Center
  • Fenton, MO
  • NPI 1700966207

  Single Specialty

  Medicare reassignment Care Compare group NPD
• Mercy Clinic East Communities

  • Internal Medicine Physician
  • Saint Louis, MO
  • NPI 1851335228

  Single Specialty

  Medicare reassignment NPD
• Mercy Clinic East Communities

  • Family Medicine Physician
  • Saint Louis, MO
  • NPI 1720635329

  Single Specialty

  NPD
• SSM Medical Group Inc.

  • Durable Medical Equipment & Medical Supplies
  • Warrenton, MO
  • NPI 1467997155
  NPD
• Mercy Hospital South

  • General Acute Care Hospital
  • Saint Louis, MO
  • NPI 1568481984

  Single Specialty

  NPD (past)
• SSM Health Care St. Louis

  • Emergency Medicine Physician
  • Saint Charles, MO
  • NPI 1427002922

  Single Specialty

  NPD (past)

Hospitals and other facilities this clinician is affiliated with according to Medicare Care Compare.

• SSM Health Care St. Louis

  • General Acute Care Hospital
  • Saint Charles, MO
  • NPI 1467521146
  Care Compare affiliation

The complete NPPES record for this NPI in the NPI Registry API format.

{
    "created_epoch": "1497484800000",
    "enumeration_type": "NPI-1",
    "last_updated_epoch": "1762732800000",
    "number": "1972033652",
    "addresses": [
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "MAILING",
            "address_type": "DOM",
            "address_1": "PO BOX 955534",
            "city": "SAINT LOUIS",
            "state": "MO",
            "postal_code": "631955534",
            "telephone_number": "557-203-1531"
        },
        {
            "country_code": "US",
            "country_name": "United States",
            "address_purpose": "LOCATION",
            "address_type": "DOM",
            "address_1": "1101 HIGHWAY K",
            "city": "O FALLON",
            "state": "MO",
            "postal_code": "633668431",
            "telephone_number": "636-379-6363"
        }
    ],
    "practiceLocations": [
        {
            "address_1": "615 S New Ballas Rd",
            "address_purpose": "LOCATION",
            "city": "Saint Louis",
            "state": "MO",
            "postal_code": "631418221",
            "country_code": "US",
            "telephone_number": "314-251-6062",
            "fax_number": "314-251-4376",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "address_1": "12700 Southfork Rd Ste 230",
            "address_purpose": "LOCATION",
            "city": "Saint Louis",
            "state": "MO",
            "postal_code": "631283276",
            "country_code": "US",
            "telephone_number": "314-849-3711",
            "country_name": "United States",
            "address_type": "DOM"
        }
    ],
    "basic": {
        "last_name": "WILLIAMS",
        "first_name": "ALEXA",
        "middle_name": "JO DULING",
        "credential": "MD",
        "sole_proprietor": "YES",
        "sex": "F",
        "enumeration_date": "2017-06-15",
        "last_updated": "2025-11-10",
        "certification_date": "2025-11-10",
        "status": "A"
    },
    "taxonomies": [
        {
            "code": "207V00000X",
            "taxonomy_group": "193400000X SINGLE SPECIALTY  GROUP",
            "desc": "Obstetrics & Gynecology",
            "state": "MO",
            "license": "2021013439",
            "primary": true
        },
        {
            "code": "207V00000X",
            "taxonomy_group": "193400000X SINGLE SPECIALTY  GROUP",
            "desc": "Obstetrics & Gynecology",
            "state": "MO",
            "license": "2017019537",
            "primary": false
        }
    ],
    "identifiers": [],
    "endpoints": [
        {
            "endpointType": "FHIR",
            "endpointTypeDescription": "FHIR URL",
            "endpoint": "https://fhir.ssmhc.com/fhir/api/FHIR/DSTU2/",
            "affiliation": "N",
            "use": "OTHER",
            "useDescription": "Other",
            "useOtherDescription": "FHIR API",
            "contentType": "OTHER",
            "contentTypeDescription": "Other",
            "contentOtherDescription": "CCD",
            "address_1": "1101 Highway K",
            "city": "O Fallon",
            "state": "MO",
            "country_code": "US",
            "postal_code": "633668431",
            "country_name": "United States",
            "address_type": "DOM"
        },
        {
            "endpointType": "DIRECT",
            "endpointTypeDescription": "Direct Messaging Address",
            "endpoint": "awilliams558665@direct-ehr-ssmhc.com",
            "affiliation": "N",
            "use": "DIRECT",
            "useDescription": "Direct",
            "contentType": "OTHER",
            "contentTypeDescription": "Other",
            "contentOtherDescription": "awilliams558665@direct-ehr-ssmhc.com",
            "address_1": "1101 Highway K",
            "city": "O Fallon",
            "state": "MO",
            "country_code": "US",
            "postal_code": "633668431",
            "country_name": "United States",
            "address_type": "DOM"
        }
    ],
    "other_names": []
}

• Robert D Wiele, MD
• Keith Thomas Wiethaupt
• Chandra K Wiewel, M.D.
• Kevin J Wilhite, PT
• Sarah Wille
• Ashley R Williams, DPT
• Cynthia Lynn Williams, LCSW
• Jonathan Paul Williams, MD
• Michael A Williams, DC
• Rachel Williams I, DPT

• Obstetrics & Gynecology Physician in O Fallon, MO
• Providers in O Fallon, MO by specialty
• Obstetrics & Gynecology Physician in Missouri

• NPPES NPI Registry (CMS): identity, addresses, specialties, licenses, identifiers and endpoints. Last updated by the provider on Nov 10, 2025; self-reported and not verified by CMS. Specialty names from the NUCC taxonomy.
• Medicare enrollment (CMS PECOS): enrollments, PAC IDs and benefit reassignments; Order and Referring.
• Medicare Care Compare (CMS): clinician profile, group practices, facility affiliations, MIPS scores and star ratings.
• National Provider Directory (CMS): practice roles, locations, licenses, networks and endpoints.

Verify at the official NPI Registry.