Abstract The University of Pennsylvania's Department of Obstetrics and Gynecology reflects a long tradition of excellence in clinical and translational research. In this application, information is provided on the obstetrical service and proven track record for conducting clinical trials at two hospitals in the University of Pennsylvania (Penn) Health System – the Hospital of the University of Pennsylvania (HUP) and Pennsylvania Hospital (PAH). Each year, approximately 9,500 patients are delivered at Penn, and many of these patients have high- risk pregnancies. The obstetric population at Penn has a diverse racial and ethnic background, which is an important asset for enrollment in Maternal-Fetal Medicine Units (MFMU) Network studies. Key assets of the MFMU Network site at Penn are: 1) an experienced Nurse Coordinator who oversees all the clinical studies; 2) a second registered nurse who is critical for completion of complicated Network studies (e.g., PACT, PASC- PREG); 3) a biospecimens technician who has written manuals of operation and oversees collection, processing, and data banking for biospecimens; 4) successful outpatient recruitment at all major clinical sites at HUP and PAH; 5) the ability to expand to a 24/7 model that provides coverage on the labor and delivery units at HUP and PAH; 6) data abstraction manuals for each MFMU Network study that ensure accurate ascertainment of clinical data from the electronic medical record; and 7) support by the MFM Research Program and the Women's Health Clinical Research Center at Penn, which assist the MFMU Network team with recruitment of new staff, onboarding, regulatory affairs, and good clinical practices in all research operations. The MFMU Network research team works closely with the Neonatal Research Network clinical center at the Children's Hospital of Philadelphia to provide neonatal follow-up for MFMU Network studies. The investigative team for the MFMU Network clinical center at Penn has substantial experience directing multicenter studies, and each investigator has an exciting research agenda that adds unique perspectives to the MFMU Network. The investigators propose three specific aims for this application: 1) Develop and implement MFMU Network protocols, including recruitment, study interventions, and follow-up examinations; 2) Provide the highest quality data for MFMU Network studies and provide these data in a timely fashion; and 3) Collaborate with the other MFMU Network centers to identify areas for potential research and to analyze and publish studies performed by the MFMU Network. The investigative team at Penn has built a highly successful MFMU Network clinical site that will support the NICHD's guiding principles shaping the 21st century landscape for multi-site clinical research, including enhanced rigor for selecting studies, availability of Network infrastructure to a wider range of investigators, data sharing and access to biospecimens, and inclusion of diverse populatio...