Robert Day, M.D.
Robert Day, M.D. is a Maternal & Fetal Medicine Physician in Irvine, CA, registered under NPI 1841618634. This provider registers 2 separate taxonomy codes, which usually means they practise across more than one recognised specialty.
Getting there
The practice address on file is 16305 SAND CANYON AVE STE 225, Irvine, CA 92618. We have not yet mapped what surrounds this office — parking, transit, and nearby pharmacies are added as our data collection reaches each location.
Credentials and Medicare
| Licence | State | Specialty |
|---|---|---|
| A139689 | CA | Maternal & Fetal Medicine Physician primary |
| A139689 | CA | Obstetrics & Gynecology Physician |
This provider holds licence A139689 issued in CA. A licence number in NPPES reflects what was filed at registration — it does not confirm the licence is still active today.
- Status
- Approved
- Provider type
- Practitioner - Obstetrics/gynecology
- PAC ID
- 6204129315
- Enrollment ID
- I20180425001142
Medicare enrolment is recorded as approved under the provider type Practitioner - Obstetrics/gynecology. Being enrolled means the provider can bill Medicare; it does not tell you whether they are currently accepting new Medicare patients. Call the office to confirm.
What Maternal & Fetal Medicine covers
An obstetrician/gynecologist who cares for, or provides consultation on, patients with complications of pregnancy. This specialist has advanced knowledge of the obstetrical, medical and surgical complications of pregnancy and their effect on both the mother and the fetus. The specialist also possesses expertise in the most current diagnostic and treatment modalities used in the care of patients with complicated pregnancies. NUCC Health Care Provider Taxonomy, code 207VM0101X
All registered taxonomy codes
This provider registers 2 taxonomy codes. The primary code is what appears on most claims; the others record additional recognised specialties.
| Code | Specialty | Licence | State | |
|---|---|---|---|---|
| 207VM0101X | Maternal & Fetal Medicine Physician Maternal & Fetal Medicine | A139689 | CA | primary |
| 207V00000X | Obstetrics & Gynecology Physician | A139689 | CA |
The taxonomy records how the provider classifies their own practice. It does not confirm which conditions they currently treat, whether they are accepting new patients, or which insurance they take — call the office for that.
Full NPPES record
An NPI-1 identifies a single person. It stays with the clinician for life, even if they move practice or change state, which is why the address on file can lag behind where they actually work today.
| NPI | 1841618634 valid check digit |
|---|---|
| Entity type | Individual (NPI-1) |
| Enumeration date | Mar 31, 2014 |
| Last updated | Jun 17, 2025 |
| Status | Active |
| Sole proprietor | No |
| Credential | M.D. |
| Practice address |
16305 SAND CANYON AVE STE 225 Irvine, CA 92618 (949) 763-7451 |
| Mailing address |
395 CENTRAL ST Milford, MA 01757 |
Number check
How the check works, step by step
Every NPI carries a Luhn check digit — the same scheme used on credit cards. CMS prefixes the number with 80840 before computing it, which marks it as a US health identifier.
| Digit | 8 | 0 | 8 | 4 | 0 | 1 | 8 | 4 | 1 | 6 | 1 | 8 | 6 | 3 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Doubled? | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 | — | ×2 |
| Value | 8 | 0 | 8 | 8 | 0 | 2 | 8 | 8 | 1 | 3 | 1 | 7 | 6 | 6 |
Sum = 66 · next multiple of 10 = 70 · check digit = 4 · actual last digit = 4
A valid check digit only means the number is well-formed. It does not mean the provider is licensed, active, or in good standing — those are separate questions answered by the sections above.