U.S. doctors online nowAsk doctors free

Dr. Nikolaos Zacharias

Maternal-Fetal Medicine
Houston, TX
26 years experience male



Houston, TX


5656 Kelley Street, Houston, TX

My office hours

Wednesday: 8:00am - 5:00pm
Show more


(713) 566-4418

Insurances accepted

Blue Cross Blue Shield of Texas







Nikolaos Zacharias, MD, FACOG, is a native of Greece; he earned his medical diploma with excellence from the National Kapodistrian University of Athens, Greece (1995) reciting the Hippocratic Oath as a top graduate in his class. Dr. Zacharias received numerous Hellenic scholarships for undergraduate and postgraduate education (1989-2002). He trained in Obstetrics Gynecology at Baylor College of Medicine, (1998-2002), elected chief resident in 2001. He received the Council of Resident Education in Obstetrics Gynecology Outstanding Academic Achievement Award four consecutive years (1999-2002) for scoring at the top 3% of his U.S. peers at these annual examinations. His passion for prenatal sonography and profound interest in pregnancy complications led him to a fellowship in Maternal-Fetal Medicine at the University of Texas Medical Branch, in Galveston, Texas (2002-2005), where he received the UTMB Hospital Academic Fellowship Award (2002-2005) and enrolled in a Masters in Medical Science post-graduate program on clinical research design (2003-2005, all courses passed with excellence, thesis defense pending). Dr. Zacharias returned to Baylor as assistant professor of Obstetrics Gynecology, in the Maternal Fetal Medicine Division (2005 - 2013). He served as medical director of the Harris Health System Prenatal Ultrasound Screening Program (2005 - 2012) and as founding medical director of the Ben Taub Maternal Fetal Medicine Prenatal Ultrasound Unit (2008 - 2012), having supervised over 30,000 prenatal sonograms. Dr. Zacharias has been an active member of the Texas Children’s Fetal Center (2006-2013), teaching faculty at Ben Taub General (2005 - 2013) and Texas Children’s Hospital (2008 - 2013). He is board-certified in Obstetrics Gynecology (2008) and Maternal Fetal Medicine (2011). Dr. Zacharias received Baylor's medical student faculty teaching award (2011) and was elected to America's Top Obstetricians Gynecologists (2012). He co-directed the maternal-fetal medicine elective clerkship at Baylor College of Medicine with Dr. Robert Carpenter (2012-2013). Dr. Zacharias is a fellow of the American College of Obstetricians Gynecologists (2010) and a regular member of the Society for Maternal-Fetal Medicine (2012). On August 2013 Dr. Zacharias became the inaugural Medical Director of Prenatal Ultrasound and Maternal-Fetal Medicine at the Center for Medical Genetics - collaborating with Geneticist Dr. Katherine Thompson. His focus will be on consultative perinatology and prenatal sonography with genetic testing, serving his beloved Southeast Texas population. Languages spoken: English, Spanish, French and Greek.

Doctors may have more than one area of specialty interest. Board certification in a specialty area means the doctor has completed formal training and has practice experience in that specialty, and has passed the certification examination from the corresponding accredited medical specialty board.

Maternal-Fetal Medicine

Obstetric Medicine

Obstetrics and Gynecology

Languages spoken


Doctor Q&A

2.7K Answers
1.1K Agrees
The number of answers this doctor has agreed with.
A female asked:
Dr. Nikolaos Zacharias
Maternal-Fetal Medicine 26 years experience
Not likely.: if pregnancy tests are negative two weeks later you should not be pregnant. Rare exceptions would include late ovulation and test failure. Consult with your gynecologist to be sure.
A 35-year-old female asked:
Dr. Nikolaos Zacharias
Maternal-Fetal Medicine 26 years experience
Hormones likely: The estrogen and progesterone surge in the second trimester commonly triggers headaches in pregnancy in predisposed women. Try Reglan + Tylenol (acetaminophen) (10 +1000 mg orally) up to 2-3 times daily to manage your symptoms, after consulting with your obstetrician.
A 23-year-old male asked:
Dr. Nikolaos Zacharias
Maternal-Fetal Medicine 26 years experience
NO: Fasting is not required to check for pregnancy hormones in your blood.

90,000 U.S. doctors in 147 specialties are here to answer your questions, provide medical advice, write prescriptions, and more.

Ask doctors free
Answer emailed
in 24 hours or less

Recommendations and Thank you notes are endorsements given from patients or other doctors.

Thank you notes
Nov 4, 2012
Dr. Zacharias is extremely well-versed in his field and consistently provides informative, practical answers to a wide variety of HealthTap questions. I enjoy learning from him!
May 11, 2013
Exceptional source of information on Maternal - Fetal Medicine. Provides an excellent public service through Health Tap. I recommend Dr. Zacharias.
Aug 10, 2015
Dr. Zacharias gives superb & accurate advice. He is certainly very experienced and is very well versed in his specialty.
HealthTap member
Want to monitor polyps on cervix that appeared w intoduction of extra estrogen from pregnancy. Were not visible two weeks before pregnancy. Want to make sure they aren't growing wildly. Make sense? I'...Read More
HealthTap member
Thanks! Feel much better. My verify was negative for downs and based on what you said that is far more accurate and I can disregard the 1 in 20. I will also take sequinom but assume the same result wi...Read More
HealthTap member
thank you. my son had numerous chd's. he had a asd, missing dividing wall between chambers, and heterotaxia. this caused him to have malrotation of the intestines, and he had asplenia. due to not havi...Read More

Education & Training

Medical/Graduate school

National University of Athens Faculty of Medicine, Greece
Graduated 1995MD


Baylor College of Medicine


UTMB Hospital Academic Fellowship Award, 2002-2005.
CREOG/ACOG outstanding Academic Achievement Award, 1999-2002.
Papadakis Undergraduate Hellenic Award, 1989-1995.


Society for Maternal-Fetal Medicine
American College of Obstetricians and Gynecologists
Harris County Medical Society
90,000 U.S. doctors in 147 specialties are here to answer your questions, provide medical advice, write prescriptions, and more.
Answer emailed
in 24 hours or less