At Extend Fertility, we practice truth-based care. We unmask the facts and counsel women to confidently address their fertility.

OUR STORY

Extend Fertility was founded on the premise that democratizing egg freezing could ultimately change the fertility industry and deliver better results.  Our co-founder, Dr. Joshua Klein, was a reproductive endocrinologist and fertility specialist at one of the nation’s leading fertility practices.  However, he observed that IVF’s low success rate for women over 40 and its high cost was disappointing for doctors and patients alike.  Dr. Klein saw the opportunity to help women think more proactively about their fertility. He believed that if more women could access their younger eggs during the IVF process, more women would see successful outcomes.

Since our founding, we have helped thousands of patients on their fertility journey through egg freezing and IVF – putting them in charge of their fertility future instead of letting time dictate the path. Extend Fertility began offering egg freezing at 40% below the national average cost. By 2017, we were the largest egg freezing practice in the nation. Since then, we have expanded to offer a full range of infertility services, including IVF, in a small practice environment that is more personal, higher quality and data driven.

We believe that no one should fear what they don’t know about their own fertility. We share a passion for delivering fertility in a more caring and transparent way.  Because ultimately, what we do every day has the potential to change lives.

OUR LAB’S CLINICAL EXCELLENCE MEANS RESULTS

Our embryology team

Our lab is led by highly experienced embryologists, scientists who specialize in human reproduction. We utilize vitrification or “flash freezing” techniques for all egg and embryo freezing. Vitrification delivers superior thaw rates - 90% for eggs and nearly 100% for embryos frozen with this technique.

State-of-the-art lab

Our lab was designed and built from scratch in 2016 to deliver optimal results. Its compact design includes a pass-through window, connecting our lab directly with our operating room. Every surface of this pass-through workstation is warmed to 37º Celsius, or human body temperature, to maintain the quality of the eggs. We have individual temperature controlled benchtop incubators that allow for precise control and stability of temperature and pH levels.

OUR TEAM

Over 40 strong, we are your doctors, fertility advisors, embryologists, nurses, medical assistants, and support team.

Joshua U. Klein

MD, FACOG

Joshua U. Klein

MD, FACOG

Close

Chief Clinical Officer, Reproductive Endocrinologist, Medical Director of the Embryology Lab

Dr. Joshua U. Klein, co-founder and Chief Clinical Officer of Extend Fertility.

Dr. Klein is a board-certified reproductive endocrinologist and assistant professor of Obstetrics, Gynecology, and Reproductive Science at the Icahn School of Medicine at Mount Sinai. He earned his medical degree at Harvard University, completing his residency in Obstetrics, Gynecology and Reproductive Biology at Massachusetts General and Brigham & Women’s Hospitals. He did his fellowship in Reproductive Endocrinology and Infertility at Columbia University and is board-certified in Obstetrics and Gynecology as well as Reproductive Endocrinology and Infertility. Before leading the Extend Fertility Medical Practice, Dr. Klein practiced for several years at one of the largest academic IVF programs in the US, where he served as medical director for Reproductive Medicine Associates of New York in Brooklyn. Dr. Klein has authored and co-authored publications in leading peer-reviewed academic journals such as Science, Fertility and Sterility, and Obstetrics and Gynecology. He has also written numerous chapters for medical textbooks and has presented research at national conferences including the American Society for Reproductive Medicine (ASRM). Dr. Klein sits on the medical board of several fertility advocacy organizations and regularly gives lectures and presentations to community groups on infertility and fertility preservation.

Bat-Sheva Lerner Maslow

MD, MSCTR, FACOG

Bat-Sheva Lerner Maslow

MD, MSCTR, FACOG

Close

Reproductive Endocrinologist, Director of Research

Dr. Bat-Sheva Lerner Maslow is a reproductive endocrinology and infertility specialist. She attended the Albert Einstein College of Medicine, earning a medical degree with distinction in reproductive endocrinology. Dr. Maslow completed residency training in obstetrics and gynecology at the University of Pennsylvania and subspecialty training in reproductive endocrinology and infertility at the University of Connecticut. Additionally, she completed a master’s program in clinical and translational research at the University of Connecticut, focusing on both medical research and the communication and application of scientific findings.

Prior to joining Extend, Dr. Maslow was an associate physician at a top-ranked private infertility practice, Gold Coast IVF, in Long Island. Dr. Maslow’s research has been published in Obstetrics & Gynecology, Fertility & Sterility, the Journal of Assisted Reproduction and Genetics, and other key medical journals. Additionally, Dr. Maslow writes and lectures on topics related to the intersection of Jewish law and reproduction. She serves as the Director of medical education for Nishmat’s North American Yoatzot Halacha Fellowship Program, which trains female scholars to address questions in Jewish law related to women’s health.

Michael Guarnaccia

MD, MPH, FACOG

Michael Guarnaccia

MD, MPH, FACOG

Close

Reproductive Endocrinologist

Dr. Michael Guarnaccia is a reproductive medicine specialist. Dr. “G” earned his medical degree at Case Western Reserve University. He went on to complete specialty training in obstetrics and gynecology at Cornell Medical Center, and his subspecialty training in reproductive endocrinology and infertility at the Yale University School of Medicine. Dr. G is double board-certified in obstetrics and gynecology and reproductive endocrinology and infertility.

Dr. G has over two decades of experience in fertility medicine, most recently as medical director at True North Fertility, and prior to that, as a physician and medical director for the Center for Women’s Reproductive Care at Columbia University, where he worked for 13 years. As CWRC’s medical director, he also founded the preimplantation genetic diagnosis (PGD) program at the CWRC, which uses cutting-edge technology to assist families struggling with potentially life-altering genetic diseases.

Recently, Dr. G continued his education at Columbia University, where he earned a master’s of public health degree in 2015 and a graduate certificate in healthcare information technology in 2017. He has also held academic appointments at Harvard University, Tufts University and most recently as an associate professor of reproductive endocrinology and infertility at Columbia University Medical Center.

Nataki Douglas

MD, PHD

Nataki Douglas

MD, PHD

Close

Consulting Reproductive Endocrinologist

Dr. Nataki C. Douglas is board certified in both obstetrics and gynecology and reproductive endocrinology and infertility. Dr. Douglas earned both her MD and PhD at Yale University School of Medicine. She completed her residency in obstetrics and gynecology as well as her fellowship in reproductive endocrinology and infertility at Columbia University Medical Center. Prior to joining the Extend Fertility Medical Practice as a consulting reproductive endocrinologist, Dr. Douglas practiced at the Center for Women’s Reproductive Care at Columbia University for 8 years.

As a practicing physician-scientist, Dr. Douglas combines basic/translational and clinical research into comprehensive patient care. As an associate professor and director of translational research for the Department of Obstetrics, Gynecology and Women’s Health at Rutgers-New Jersey Medical School, her research focuses on understanding how the reproductive system develops and what is required for successful embryo implantation and pregnancy. Dr. Douglas has authored and co-authored publications in  leading peer-reviewed academic journals including Fertility and Sterility, Endocrinology, and Obstetrics and Gynecology, and has presented her research at national conferences for the American Society for Reproductive Medicine (ASRM) and the Society for Reproductive Investigation (SRI).

Leslie Ramirez, PhD

Head of Embryology

Leslie Ramirez, PhD

Head of Embryology

Close

Dr. Leslie Ramirez obtained her master’s and PhD in Biotechnology of Human Assisted Reproduction at the University of Valencia in Spain, studying under Dr. Carlos Simón at the Instituto Valenciano de Infertilidad (Valencia Infertility Institute) Clinic Valencia.

Dr. Ramirez has performed research at institutions in the United States, Spain, United Kingdom, and Mexico, and has trained undergraduate and graduate-level students. Dr. Ramirez has contributed to multiple conferences, acts as referee for academic journals, and as a reviewer for the American Society for Reproductive Medicine (ASRM) abstract submissions. Since 2015, she has been a member of the Research Subcommittee of the ASRM and Society of Reproductive Biologists & Technologists (SBRT).

After earning her PhD, Dr. Ramirez worked as an embryologist and researcher at Brigham and Women’s Hospital at Harvard University, where she was part of the team performing the clinical trial of a new embryo time-lapse imaging system, The EevaTM Test.

Originally from Mexico, Dr. Ramirez lived in Spain as well as Boston before moving to New York in 2016.

Dayna Hennessy, MSN, NP-C

Director of Clinical Operations

Dayna Hennessy, MSN, NP-C

Director of Clinical Operations

Close

Dayna is a board-certified nurse practitioner in family health with eight years of nursing experience. She earned her Bachelor of Science in Nursing at Florida Atlantic University and her Master of Science in Nursing from Nova Southeastern University. Dayna is a member of the American Society for Reproductive Medicine (ASRM).

Dayna began her nursing career working in the emergency department at Lakeside Medical Center in Belle Glade, Florida and then moved on to serve as an operating room nurse at Good Samaritan Medical Center in West Palm Beach. Building on her practical nursing experience, Dayna transitioned to a position as a fertility nurse for Reproductive Medicine Associates of New York, where she spent three years before joining the Extend Fertility Medical Practice.

While working in the reproductive endocrinology field, Dayna also found time to teach health to high school students, fulfilling her love to educate, inform and share information.

Cara Stefanacci

Senior Fertility Advisor

Cara Stefanacci

Senior Fertility Advisor

Jordana Finkelstein

Senior Fertility Advisor

Jordana Finkelstein

Senior Fertility Advisor

Kezia Onel

Fertility Advisor

Kezia Onel

Fertility Advisor

Tamar Tenenbaum, LMSW

Fertility Advisor

Tamar Tenenbaum, LMSW

Fertility Advisor

Ilana Recca, BSN, RN

Nurse Manager

Ilana Recca, BSN, RN

Nurse Manager

Close

After completing her nursing degree at New York University Rory Meyers School of Nursing, Ilana spent two years at a nurse on a medical-surgical floor at Mount Sinai Hospital. She then moved to the burn intensive care unit at New York Presbyterian Weill Cornell Medical Center, where she worked with critically ill adults and pediatric patients for four years.

During her final year at Weill Cornell, she also took a per diem position as a nurse in their in vitro fertilization clinic. It was there that she discovered her love for the fertility field, and that experience inspired her to pursue a career in fertility medicine. Ilana is currently continuing her education at Hunter College, where she’s enrolled in their Psychiatric Mental Health Nurse Practitioner program.

Joining Extend Fertility fulfilled Ilana’s desire to work in a smaller, more intimate setting, as opposed to the large hospital setting she was used to. As a member of our team, she’s proud to be part of a constantly evolving industry that’s doing meaningful work, enabling women to have children at a time that works best for them.

Demet Yilmaz

Assistant Manager of Clinical Operations

Demet Yilmaz

Assistant Manager of Clinical Operations

Stephanie Koton, BSN, RN

Fertility Nurse

Stephanie Koton, BSN, RN

Fertility Nurse

Valerie Shafran, BSN, RN

Fertility Nurse

Valerie Shafran, BSN, RN

Fertility Nurse

Sarah Renny, BSN, RN

Fertility Nurse

Sarah Renny, BSN, RN

Fertility Nurse

Molly Spilka, MSN, RN

Fertility Nurse

Molly Spilka, MSN, RN

Fertility Nurse

Ana Baez-Castillo

Sonographer

Ana Baez-Castillo

Sonographer

Thalia Chambers

Sonographer

Thalia Chambers

Sonographer

Melissa Toledo-Fetcho, PhD

Embryologist

Melissa Toledo-Fetcho, PhD

Embryologist

Justin Roman

Embryologist

Justin Roman

Embryologist

Magdiel Aleksiev

Embryologist

Magdiel Aleksiev

Embryologist

Nanis Nassar

Embryologist

Nanis Nassar

Embryologist

Lisa Ghebretzadick

Embryologist

Lisa Ghebretzadick

Embryologist

Matthew Recio

Andrologist

Matthew Recio

Andrologist

Maha Salama

Laboratory Administrator

Maha Salama

Laboratory Administrator

Mishell Ganchala

Lab Technician

Mishell Ganchala

Lab Technician

Alexa Giovannini

Junior Embryologist

Alexa Giovannini

Junior Embryologist

Giselle Aguirre

Junior Embryologist

Giselle Aguirre

Junior Embryologist

Christina Rodriguez

Medical Assistant

Christina Rodriguez

Medical Assistant

Crystal Bryan

Medical Assistant

Crystal Bryan

Medical Assistant

Francine Williams

Medical Assistant

Francine Williams

Medical Assistant

Brenda Nunez

Medical Assistant

Brenda Nunez

Medical Assistant

Jillian Gray

Controller

Jillian Gray

Controller

Marc Silberman

Chief of Staff

Marc Silberman

Chief of Staff

Julia Webb

Director of Digital

Julia Webb

Director of Digital

Miriam Olivera

Patient Finance Manager

Miriam Olivera

Patient Finance Manager

Linda Chen

Patient Financial Advisor

Linda Chen

Patient Financial Advisor

Shari Quiles

Accounting Associate

Shari Quiles

Accounting Associate

Greg Horton

Administrator

Greg Horton

Administrator

Yamice Rentas

Patient Care Coordinator

Yamice Rentas

Patient Care Coordinator

Contact us to learn more

Let's talk