Trusted Pediatric Care by Our Expert Sudbury Team | Sudbury Team
                     WELCOME TO MILL 
BROOK PEDIATRICS
When you choose Mill Brook Pediatrics, you’re 
partnering with a team of compassionate and 
highly skilled professionals devoted entirely to your 
child’s health and well-being. Our dedicated 
pediatricians combine medical expertise with 
genuine care, creating a warm and supportive 
environment for every family. Whether you have 
questions, concerns, or need guidance through 
your child’s developmental stages, we’re here to 
help every step of the way. At Mill Brook Pediatrics, 
we’re more than just a clinic—we’re your trusted 
partner in nurturing a lifetime of health and 
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490C Boston Post Road Sudbury, MA 01776
ABOUT MILL BROOKS 
PEDIATRICS Mill Brook Pediatrics: A Legacy of Compassionate Pediatric Care in Sudbury
About Us 
Founded in 1994 by Dr. Lauren Geddes, Mill Brook Pediatrics 
has been a trusted name in child-centered healthcare for 
families in the greater Sudbury area. Originally established 
as a small, community-focused practice, it moved in 2001 
to its current home in the Emerson Medical Building at 490C 
Boston Post Road, Sudbury. After decades of exceptional 
service, Dr. Geddes and her husband, Dr. Bill Wirth, proudly 
transitioned the practice to Weston Pediatric Physicians, PC, 
a well-respected name in pediatric care since 1964. 
Together, this collaboration strengthens our mission to 
provide comprehensive and compassionate healthcare to a 
wider Metro West community.
24/7 Pediatric Coverage
 Your child’s health is our priority—day and night. Our 
pediatricians are available 24 hours a day, 7 days a week, 
including weekends and holidays. We also offer urgent care 
hours at our Weston office for added convenience, available 
by appointment following nurse triage.
Convenient, Integrated Care
 Located within the Emerson Medical Building, Mill Brook 
Pediatrics provides seamless access to multiple outpatient 
services such as lab work, X-rays, and other medical 
specialties, including Internal Medicine, OB-GYN, 
Orthopedics, Surgery, and Podiatry—all under one roof for 
your family’s convenience.
Hospital Affiliations & Network
 Our physicians maintain active staff privileges at leading 
hospitals such as Emerson Hospital in Concord, Brigham 
and Women’s Hospital, and Newton-Wellesley Hospital. Mill 
Brook Pediatrics is also proud to be part of the Partners 
Community Healthcare network, ensuring your child 
receives the highest standard of coordinated medical care.
Insurance & Accessibility
 We accept most major insurance plans and encourage 
families to contact their insurance provider for coverage 
details. Our team is always happy to assist with any 
questions to make your experience smooth and stress-free.
At Mill Brook Pediatrics, we remain committed to the values 
that shaped our beginnings—personalized care, clinical 
excellence, and unwavering dedication to children’s health.
OUR SUDBURY 
STAFF
Our caring medical and administrative Our Sudbury Staff is 
eager to welcome you and your child, ensuring a warm and 
supportive healthcare experience. Please share any questions 
or concerns—our staff is always ready to assist you promptly 
and compassionately.
Karen Ashworth, FNP, 
AE-C
Karen, a dedicated Family Nurse Practitioner, joined Weston 
Pediatrics in March 2011, bringing extensive experience in 
pediatric and family medicine. With a Master of Science from 
Regis College and a background in psychology, she specializes 
in concussion management and asthma education. Passionate 
about adolescent care, she focuses on supporting at-risk teens, 
adolescent-GYN, and integrative health while promoting 
education and prevention through compassionate, patient-
centered care.
Katherine M. 
Bui, MD
Dr. Katherine Bui received her undergraduate degree from 
Scripps College, in Claremont, California, and her M.D. from 
Boston University School of Medicine. Dr. Bui completed her 
residency at Massachusetts General Hospital where she 
pursued particular interests in infant development and medical 
education. She is board certified in pediatrics and is a member 
of the Massachusetts Medical Society and the American 
Academy of Pediatrics. Dr. Bui is in the office on Monday, 
Tuesday and Wednesday from 8am–5pm, and Friday from 
8am–12pm
Rosemarie Dieffenbach, MD, 
MPH
Dr. Rose Dieffenbach, a board-certified pediatrician and fellow 
of the American Academy of Pediatrics, brings global 
experience and deep clinical expertise to her practice. After 
earning degrees from UCLA, the University of Michigan, and 
George Washington University, she completed her residency at 
UCSF and served as a U.S. Navy pediatrician in Japan, Italy, 
and Washington. Before joining Weston Pediatrics, she 
provided emergency care at Boston Children’s Hospital. 
Dedicated to children’s health at every stage, Dr. Dieffenbach 
offers compassionate, comprehensive care and is available in 
the office Mondays and Fridays (8am–12pm) and Wednesdays 
and Thursdays (8am–5pm).
Robert H. Andler, MD, FAAP
Dr. Robert Andler, a board-certified pediatrician and fellow of 
the American Academy of Pediatrics, brings extensive 
experience and compassionate care to every family he serves. 
A graduate of Cornell University and the University of Virginia 
School of Medicine, he completed his pediatric internship and 
residency at Hasbro Children’s Hospital and Brown University 
in Rhode Island. Before joining Weston Pediatrics, Dr. Andler 
practiced in Rhode Island, where he developed a strong 
reputation for his patient-centered approach. He is available in 
the office Mondays (8am–8pm), Wednesdays and Fridays 
(8am–5pm), and Thursdays (8am–12pm).
Shelly C. Bernstein, MD
Dr. Bernstein brings an exceptional blend of medical expertise, 
research experience, and compassionate care to Weston 
Pediatrics. He earned his A.B. and Ph.D. in Genetics and his 
M.D. from The University of Chicago, followed by a pediatric 
residency at Boston Children’s Hospital and a hematology-
oncology fellowship at both Children’s Hospital and the Dana-
Farber Cancer Institute. Before joining Weston Pediatrics in 
1990, Dr. Bernstein led a distinguished research career. As an 
Assistant Clinical Professor of Pediatrics at Harvard Medical 
School, he continues to mentor future physicians while 
providing outstanding patient care. Board-certified in 
pediatrics and a fellow of the American Academy of Pediatrics, 
Dr. Bernstein has a strong clinical focus on hematology and 
oncology, also caring for young patients at The Jimmy Fund at 
Dana-Farber. He is available in the office Monday, Tuesday, and 
Thursday (8am–5pm) and Wednesday (1pm–8pm).
THANK YOU
Phone: 978-443-
0707
490C Boston Post Road Sudbury, 
MA 01776