Karen O'Brien, M.D.
NPI 1780623215 · Maternal & Fetal Medicine Physician · South Weymouth, MA
Enrolled with Medicare as Practitioner - Obstetrics/Gynecology · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Karen O'Brien, M.D. is a Maternal & Fetal Medicine Physician provider in South Weymouth, MA (NPI 1780623215).
Provider details
- NPI number
- 1780623215
- Entity type
- Individual
- Primary specialty
- Maternal & Fetal Medicine PhysicianAllopathic & Osteopathic Physicians
- Credential
- M.D.
- Sex
- Female
- Sole proprietor
- No
- License
- 218797 (MA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
20 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
3 documented practice locations
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
Practice location
Mailing address
Additional practice locations (2)
- 330 Brookline AveBoston, MA 02215-5400Phone: (617) 667-4836
- 51 Performance DrWeymouth, MA 02189-3141Phone: (781) 624-8000
Registry dates
- Enumerated
- 2006-06-06
- Last updated
- 2023-10-19
- Certified
- 2023-10-19
Frequently asked questions
- What is Karen O'Brien's NPI number?
- Karen O'Brien's National Provider Identifier (NPI) is 1780623215, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Karen O'Brien's specialty?
- Karen O'Brien is listed in the NPPES registry with a primary specialty of Maternal & Fetal Medicine Physician (Allopathic & Osteopathic Physicians).
- Where is Karen O'Brien located?
- Karen O'Brien's practice location on file with NPPES is 55 Fogg Rd, South Weymouth, MA 02190-2432.
- What is Karen O'Brien's phone number?
- The practice phone number listed in the NPPES registry for Karen O'Brien is (781) 624-8000.
- Does Karen O'Brien accept Medicare?
- Karen O'Brien is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Karen O'Brien's NPI active?
- Yes — Karen O'Brien's NPI (1780623215) is active in the NPPES registry as of the last update on 2023-10-19.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.