Alexandra “Lex” Mastro, DMSc, MPAS, PA-C

Physician Assistant, Neonatology  

Nemours Children's Health 

Alexandra “Lex” Mastro is a board-certified physician assistant in neonatology who is passionate about providing exceptional care to newborns and their families. She brings extensive experience to Nemours Children’s Health, having worked at UPMC Magee-Womens Hospital, UPMC Children’s Hospital of Pittsburgh, and UPMC Hamot in Erie, Pennsylvania. Most recently, Lex served as the Advanced Practice Provider (APP) Supervisor for the Division of Newborn Medicine in Central Pennsylvania, where she cared for patients across UPMC Carlisle, Harrisburg, Lititz, and Memorial hospitals.  

Lex earned her Doctor of Medical Science (DMSc) degree from A.T. Still University in Fall 2024, building on a strong educational foundation that includes a Bachelor of Science in Health Science and a Master of Physician Assistant Studies (MPAS) from Gannon University. She completed her neonatology fellowship at UPMC in 2017 and earned an APP Leadership Certificate from the University of Pittsburgh in 2022.  

An NRP (Neonatal Resuscitation Program) and STABLE instructor, Lex is dedicated to education and mentorship. She has served as the Associate Director of the Advanced Practice Provider Neonatology Fellowship Program and played an active role on several advisory committees, including co-chairing the Central Pennsylvania APP Service Subcommittee and serving on the Education Subcommittee at UPMC Children’s. In 2024, she was honored as the Central Pennsylvania APP Leader of the Year. 

Lex’s clinical interests include neonatal ECMO, mortality reviews, and advancing care for lower-risk chorioamnionitis babies and periviable infants born at 22-24 weeks gestation. She is also an active member of the Pennsylvania Society of Physician Associates (PSPA) and serves in the American Academy of Physician Associates (AAPA) House of Delegates.  

Lex recently relocated to Wilmington, Delaware, with her partner, Kelley, a Licensed Professional Counselor and Certified Child Life Specialist, and their rescue dog, Tuxedo. Outside of work, she enjoys community outreach, reading, soccer, and staying active.