Rebecca A. Simmons, MD, is a professor of pediatrics at the Perelman School of Medicine at the University of Pennsylvania, with an appointment in the department of Obstetrics and Gynecology. She also serves as the Deputy Director of the Center for Excellence in Environment and Toxicology funded by the NIH. She is a PI of the March of Dimes Preterm Birth Research Center at UPENN. Dr. Simmons is the past chair of the Faculty Senate at UPENN, and the Vice-chair for the Committee for Appointments and Promotions, Department of Pediatrics.

Dr. Simmons is the principal investigator on four federally funded projects. Currently she is the principal investigator of a study entitled “Novel Biomarkers of Preterm Birth”; a study entitled “Placental Molecular Signature in Preterm Birth”; a study entitled “Mechanisms by which IUGR leads to Diabetes”. She was recently awarded an NIH grant: Novel Mechanisms Underlying the Development of Obesity which is focused on the role of extracellular vesicles in placenta development in obese pregnancies. Dr. Simmons is also the PI on an R01 entitled “Preconception phthalate exposure on offspring.”

Education and Training

Medical School

MD - University of Arizona, Tucson, AZ


Northwestern University Medical School, Chicago, IL
Children's Memorial Hospital, Chicago, IL


Pediatrics - University of Arizona Medical Center, Tucson, AZ


Cardiovascular Research Institute, University of California, San Francisco, CA

Board Certification

Neonatal-Perinatal Medicine

Titles and Academic Titles

Attending Neonatologist

Hallam Hurt Professor Pediatrics, Perelman School of Medicine at the University of Pennsylvania

Departments and Services

Research Interests

Dr. Simmons research program is focused on elucidating the mechanisms by which an adverse intrauterine milieu associated with intrauterine growth restriction, diabetes or obesity in pregnancy, and exposure to chemicals such as endocrine disruptors and lead (Pb) cause the later development of diseases such as obesity and diabetes. A second major area of interest is the mechanism by which placenta mal-development leads to the development of spontaneous preterm birth. They are exploring the role of mitochondrial dysfunction and extracellular vesicle trafficking of mtDNA and miRNAs to the early embryo and the epigenetic mechanisms underlying the development of long term adverse outcomes. Dr. Simmons has trained over 50 medical, graduate, postgraduate and clinical fellows.




Lien YC, Wang PZ, Lu XM, Simmons RAAltered Transcription Factor Binding and Gene Bivalency in Islets of Intrauterine Growth Retarded Rats. Cells. 2020 Jun 9;9(6). pii: E1435. doi: 10.3390/cells9061435. PMID: 32527043 [PubMed - in process] Free Article. Similar articles.

Elshenawy S, Pinney SE, Stuart T, Doulias PT, Zura G, Parry S, Elovitz MA, Bennett MJ, Bansal A, Strauss JF 3rd, Ischiropoulos H, Simmons RA. The Metabolomic Signature of the Placenta in Spontaneous Preterm Birth. Int J Mol Sci. 2020 Feb 4;21(3). pii: E1043. doi: 10.3390/ijms21031043. PMID: 32033212.


Russell MW, Moldenhauer JS, Rychik J, Burnham NB, Zullo E, Parry SI, Simmons RA, Elovitz MA, Nicolson SC, Linn RL, Johnson MP, Yu S, Sampson MG, Hakonarson H, Gaynor JW. Damaging Variants in Proangiogenic Genes Impair Growth in Fetuses with Cardiac Defects. J Pediatr. 2019 Jun 18. pii: S0022-3476(19)30578-5. doi: 10.1016/j.jpeds.2019.05.013. [Epub ahead of print]

Schmatz M, Srinivasan L, Grundmeier RW, Elci OU, Weiss SL, Masino AJ, Tremoglie M, Ostapenko S,  Harris MC: Surviving Sepsis in a Referral Neonatal Intensive Care Unit: Association between Time to Antibiotic Administration and In-Hospital Outcomes. J. Pediatr pii: S0022-3476(19)31081-9. DOI: 10.1016/j.jpeds.2019.08.023. PMID: 31604632.

Agawu A, Fahl C, Alexis D, Diaz T, Harris D, Harris MC, Aysola J, Cronholm PF, Higginbotham EJ: The Influence of Gender and Underrepresented Minority Status on Medical Student Ranking of Residency Programs. J Natl Med Assoc. 2019 Oct 23. pii: S0027-9684(18)30414-0. doi: 10.1016/j.jnma.2019.09.002. PMID: 31668360.


Xin F, Fischer E, Krapp C, Krizman EN, Lan Y, Mesaros C, Snyder NW, Bansal A, Robinson MB, Simmons RA, Bartolomei MS. Mice exposed to bisphenol A exhibit depressive-like behavior with neurotransmitter and neuroactive steroid dysfunction. Horm Behav. 2018 May 12. pii: S0018-506X(18)30023-0. doi: 10.1016/j.yhbeh.2018.05.010. [Epub ahead of print]

Jensen EA, Foglia EE, Dysart KC, Simmons RA, Aghai ZH, Cook A, Greenspan JS, DeMauro SB. Adverse effects of small for gestational age differ by gestational week among very preterm infants. Arch Dis Child Fetal Neonatal Ed. 2018 May 5. pii: fetalneonatal-2017-314171. doi: 10.1136/archdischild-2017-314171. [Epub ahead of print]

Alexander J, Teague AM, Chen J, Aston CE, Leung YK, Chernausek S, Simmons RA, Pinney SE. Offspring sex impacts DNA methylation and gene expression in placenta from women with diabetes during pregnancy. PLoS One. 2018 Feb 22;13(2):e0190698. doi: 10.1371/journal.pone.0190698. eCollection 2018.

Gaynor JW, Parry S, Moldenhauer JS, Simmons RA, Rychik J, Ittenbach RF, Russell WW, Zullo E, Ward JL, Nicolson SC, Spray TL, Johnson MP. The impact of the maternal-fetal environment on outcomes of surgery for congenital heart disease in neonates. Eur J Cardiothorac Surg. 2018 Feb 13. doi: 10.1093/ejcts/ezy015. [Epub ahead of print] PMID: 29447332 [PubMed - as supplied by publisher]

Stuart TJ, O'Neill K, Condon D, Sasson I, Sen P, Xia Y, Simmons RA. Diet-induced obesity alters the maternal metabolome and early placenta transcriptome and decreases placenta vascularity in the mouse. Biol Reprod. 2018 Jan 18. doi: 10.1093/biolre/ioy010. [Epub ahead of print] PMID: 29360948

Rashid CS, Lien YC, Bansal A, Jaeckle-Santos LJ, Li C, Won KJ, Simmons RA. Transcriptomic analysis reveals novel mechanisms mediating islet dysfunction in the intrauterine growth restricted (IUGR) rat. Endocrinology. 2018 Jan 4. doi: 10.1210/en.2017-00888. [Epub ahead of print] PMID: 29309562


Gordon SM, Srinivasan L, Harris MC. Neonatal Meningitis: Overcoming Challenges in Diagnosis, Prognosis and Treatment with Omics. Front Pediatr. 5: 139, 2017. PMID: 28670576.


Tran PV, Kennedy BC, Lien YC, Simmons RA, Georgieff MK. Fetal iron deficiency induces chromatin remodeling at the Bdnf locus in adult rat hippocampus. Am J Physiol Regul Integr Comp Physiol. 2014 Dec 17:ajpregu.00429.2014. doi: 10.1152/ajpregu.00429.2014. [Epub ahead of print]. Read the abstract.


Simmons RA: Preclampsia and prematurity as precursors to adolescent obesity. J Pediatr 162: 889-890, 2013.

Simmons RA: Programming of DNA methylation in type 2 diabetes. Diabetologia 56: 947-948, 2013. Invited commentary.


Pinney SE, Simmons R: Metabolic programming, epigenetics, and gestational diabetes mellitus. Curr Diab Rep 12: 67-74, 2012.

Simmons RA: Developmental Origins of Diabetes: The Role of Oxidative Stress. Best Pract Res Clin Endocrinol Metab 26: 701-708, 2012, NIHMS 375424.


Simmons RA: Abnormalities of Fetal Growth in Avery's Diseases of the Newborn. Avery's Diseases of the Newborn. SU Devaskar, CA Gleason (eds.). WB Saunders, Philadelphia, Page: 51-59, 2011.

Simmons RA: Cell glucose transport and glucose handling during fetal and neonatal development. Fetal and Neonatal Physiology Fourth Edition. R Poin, W Fox, S Abman (eds.). Elsevier Saunders, Philadelphia, Page: 560-568, 2011.

Simmons R: Epigenetics and maternal nutrition: nature v. nurture. Proc Nutri Soc 70: 73-81, 2011.

French HM, Simmons RA: Infant of a Diabetic Mother in Rudolph's Pediatrics, 22nd edition. Rudolph's Pediatrics. C Rudolph, G Lister, A Gershon, L First, A Rudolph (eds.). McGraw-Hill, New York, 2011.


Sen S, Simmons RA. Maternal Antioxidant Supplementation Prevents Adiposity in the Offspring of Western diet-fed Dams. Diabetes. Epub 2010 Sep 7.  Read the abstract.

Editorial and Academic Positions

Editorial Positions

2018-present, Biology of Reproduction, Editorial Board

Academic and Institutional Committees

2012-present, The Journal of Nutritional Biochemistry, Associate Editor

2012-present, American Journal of Physiology, Endo & Metabolism, Associate Editor