Type 1 · Individual ✓ Active NPI ✓ Valid NPI checksum

Ellen C Hayes, MD

Reproductive Endocrinology Physician in Wauwatosa, WI · enumerated 2006 · practices at Vios Fertility Institute Chicago.

Data current as of Jul 13, 2026 · sourced from CMS NPPES

National Provider Identifier

1174546899

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Registry record

Entity type Individual (Type 1)

Name Ellen C Hayes

Credential MD

Sex Female

Practice address 2500 N Mayfair Rd Ste 420, Wauwatosa, WI, 53226

Phone (262) 518-7448

Enumeration date Jul 25, 2006

Last updated in NPPES May 23, 2024

Taxonomy & licenses

207VE0102X Reproductive Endocrinology Physician Allopathic & Osteopathic Physicians · License 35.148645 (OH) Secondary

207VE0102X Reproductive Endocrinology Physician Allopathic & Osteopathic Physicians · License 036.143473 (IL) Secondary

207VE0102X Reproductive Endocrinology Physician Allopathic & Osteopathic Physicians · License 4301116595 (MI) Secondary

207VE0102X Reproductive Endocrinology Physician Allopathic & Osteopathic Physicians · License 61401 (MN) Secondary

207VE0102X Reproductive Endocrinology Physician Allopathic & Osteopathic Physicians · License MD61493841 (WA) Secondary

207VE0102X Reproductive Endocrinology Physician Allopathic & Osteopathic Physicians · License 40314-20 (WI) Primary

MD · Doctor of Medicine: A physician who completed medical school (allopathic medicine), residency training, and state licensure. About the MD credential

What is an NPI number?

A National Provider Identifier (NPI) is a unique 10-digit number that CMS assigns to every U.S. healthcare provider and organization under HIPAA. Type 1 NPIs identify individual providers; Type 2 NPIs identify organizations. The NPI appears on insurance claims, prescriptions, and credentialing paperwork, and never changes, even if the provider moves or changes specialty.

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Frequently asked questions

Is this the official NPI registry?

No. NPI Portal is a private site built on public CMS NPPES data. The official registry is npiregistry.cms.hhs.gov, operated by CMS.

What specialty is Ellen Hayes?

Ellen Hayes is registered in NPPES with the primary taxonomy of Reproductive Endocrinology Physician. The taxonomy code describes the provider's classification and area of specialization for claims and credentialing.

Other providers at this practice address

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Vios Fertility Institute Chicago Reproductive Endocrinology Physician · Wauwatosa, WI NPI 1831849132

Source: CMS NPPES (public data). Snapshot 2026-07-13. Provider record last updated 2024-05-23.