Cornell's REI Fellowship

The Reproductive Endocrinology and Infertility (REI) Fellowship in the Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine at the New York Presbyterian Hospital-Weill Cornell Medical Center offers intensive instruction in reproductive disorders and tubal reconstruction, as well as correction of congenital anomalies of the reproductive tract, and complemented by a comprehensive program of basic and clinical research. With over 3500 IVF cycles and over 100,000 patient visits per year, the program includes a broad experience in the newest reproductive techniques, embryology and molecular genetics. An interdisciplinary faculty (reproductive endocrine, pediatric endocrine, medical endocrine and genetics) provides a rich scientific and clinical environment with a wide variety of special interests including, but not limited to, preimplantation genetic diagnosis, genetic analysis of spermatozoa and immature spermatids, studies on mechanisms of fertilization and early embryonic development, investigation of various reproductive disease, human embryonic stem cell derivation and fertility preservation. The fellowship is a three-year course of intensive instruction in Reproductive Endocrinology and Infertility and is currently accredited by the American Board of Obstetrics & Gynecology.  The breakdown of instruction is 18 months devoted to laboratory and clinical investigation, 12 months of clinical reproductive endocrinology and 6 months of electives (research or clinical).

Reproductive Endocrinology: Basic Science and Clinical Applications

Through didactics, directed reading and direct clinical and laboratory exposure, our fellows obtain a thorough understanding of the structures, synthesis, binding, function and mechanisms of action of reproductive hormones and their complex interactions with the endocrine system at large (e.g., as integrated with the hypothalamic-pituitary and thyroid/adrenal axes) in both healthy women (pregnant and non-pregnant) and women in states of disease or dysfunction. Fellows spend time in our Endocrine Laboratory gaining a thorough understanding of the range of endocrine assays including RIA and ELISA for estradiol, FSH, LH, progesterone and BhCG. In addition to learning about these assays and their limitations in general, the fellows gain first-hand experience in those assays related to their research. 

The unique function, interplay and potential pathophysiology of the maternal and fetal endocrine systems in pregnancy and parturition are studied. The fellows' knowledge base is further extended to the applied pharmacology of these hormones and their synthetic derivatives, including but not limited to ovulation induction (in the anovulatory patient) and super-ovulation (both for IUI and IVF), hormone replacement, hormonal contraception and the clinical management of endocrinopathies (including hyperprolactinemia, hypothalamic amenorrhea, polycystic ovarian syndrome and the spectrum of hyperandrogenism, enzyme deficiencies, etc.). The gross and microscopic anatomy and pathology of the endocrine system, both functional and neoplastic, are also fully explored.

The fellows attain expertise in the diagnosis and management (medical and surgical) of the various endocrinopathies and infertility from direct clinical experience, mentorship, didactics and directed study. Endocrine disorders commonly encountered and managed at this center include neuroendocrine disorders (e.g., hypothalamic amenorrhea, hyperprolactinemia); eating disorders; gonadal disorders including premature ovarian failure; menopause; ovarian neoplasms; PCOS; thyroid and adrenal disease (including hypo- and hyperthyroidism, adrenal enzyme deficiencies, the role of the adrenal in disorders of androgen excess, etc.); hyperandrogenemia of multiple etiologies; disorders of puberty (e.g., precocious puberty and pubertal delay, primary amenorrhea); abnormal uterine bleeding; and the full gamut of male and female infertility.  Fellows become adept at selecting and in appropriate instances performing diagnostic procedures for these disorders (such as static and dynamic hormonal testing), including an understanding of the assays employed. Fellows also gain expertise in reviewing and interpreting imaging studies including ultrasound, MRI, hysterosalpingography and sonohysterography. In addition, fellows have first-hand experience performing ultrasound and sonohysterogram examinations as well as hysterosalpingograms. The full clinical spectrum of ovulation induction and ART including the mitigation/management of associated risks are included in this experience, and the psychological aspects (and adjunctive management) of reproductive endocrine disorders and infertility are a part of the fellowship training experience.

The training program further cultivates an understanding of the role and interplay of genetics and the immune system in reproductive endocrine function and disease. Normal genetics, diagnostics at the chromosomal and single gene levels, genetically-determined disease states and the role of genetics in sporadic and recurrent pregnancy loss are reviewed and managed in clinical practice. The technology, utility, limitations and ethical dilemmas surrounding preimplantation genetic testing are also explored. Fellows are expected to attain, through reading, didactics and direct clinical experience, an understanding of immune system structure and function, as well as the full spectrum of relevant immunopathologies (including but not limited to autoimmune endocrinopathies, recurrent pregnancy loss, anti-gamete and antigonadal antibodies) and the application of immunology in applied laboratory technology (e.g., immunoassays) and basic research (e.g., immuno-histochemical techniques).

Embryology and Assisted Reproductive Technology

The development, structure, physiology and function of gametes and pre- and post-implantation embryos are studied, with a focus on genetics and fertilization, events occurring during implantation, as well as normal and abnormal fertilization and the anatomy and function of the endometrium. The clinical applications of this knowledge are fully explored in the setting of a high-volume in vitro fertilization program. The fellows are exposed to the embryology laboratory and gain a thorough understanding of the techniques of IVF, ICSI, preimplantation genetic screening and diagnosis (polar body, blastomere and trophectoderm biopsy) and the specific laboratory and molecular techniques employed for genetic analysis of single cells including PCR, FISH, CGH and microarray, as well as cryopreservation techniques including slow-freezing and vitrification. Fellows gain experience in the full range of third-party reproduction options that are currently available, including donor gametes and embryos and gestational surrogacy. With a preeminent cancer center in our tri-institutional network, the fellows gain direct experience in the counseling and evaluation of patients who have been diagnosed with neoplastic or related disorders that will pose a direct and/or indirect threat to their ability to achieve pregnancy in the future.

An active research program and full range of fertility preservation services are available at the Center, including: ART for oocyte cryopreservation (including specialized stimulation protocols for patients with estrogen- sensitive tumors), as well as embryo and ovarian tissue cryopreservation. The fellows are conversant in the physiologic and anatomic expression and impact of sporadic and environmentally- and/or genetically-mediated abnormalities of embryogenesis and fetal development (e.g., Klinefelter's syndrome, Turner's syndrome, enzyme deficiencies/ambiguous genitalia, Müllerian and Wolffian anomalies) and their diagnosis, as well as their medical and surgical management. The study of embryos extends to an understanding of embryonic stem cell derivation and its potential clinical applications.

Surgery for Reproductive Disorders

Hands-on surgical experience is extensive and includes diagnostic and operative hysteroscopy (for management of polyps, myomas, intrauterine adhesions and correction of uterine anomalies including repair of the septate uterus) in addition to treatment of longitudinal and transverse vaginal septums. The fellows perform and assist in diagnostic and operative laparoscopy (surgical management of endometriosis, pelvic adhesions, salpingostomy or salpingectomy for ectopic pregnancy, salpingectomy for hydrosalpinx, ovarian cystectomy, laparoscopic suturing for ovarian transposition and oophoropexy, treatment of the non-communicating rudimentary uterine horn with an endometrial cavity, myomectomy and LAVH). The fellows additionally gain exposure to robotic techniques (particularly for myomectomy and tubal reanastomosis), microsurgery and open laparotomy (e.g. myomectomy, extensive endometriosis and pelvic adhesions, tubal reanastomosis).  Fellows are also trained in the surgical and non-surgical treatment modalities available for the management of vaginal agenesis.


An integral part of the fellowship is exposure to and direct participation in clinical and basic research, culminating in the fellows' third-year theses. This experience enables graduates aspiring to academic careers to acquire the necessary skills to pursue their own research (and in turn mentor their own trainees) and additionally refines the fellows' ability to critically read the medical and scientific literature. Fellows are trained to develop a hypothesis and execute an appropriate study design to address their hypothesis, including power analysis. A comprehensive review of the extant literature relevant to the study question is undertaken and reviewed by their mentor who has particular expertise in that area. Where applicable, the fellow completes and submits the protocol and consents for IRB review and approval. Each fellow learns how to acquire relevant data, master experimental techniques and understand the reliability and pitfalls of the methodology, thoroughly appreciate the importance of reproducibility and the impact of potential confounders (e.g., population comparability), learn and apply statistical analyses appropriate to the data set and formulate appropriate conclusions. Presentation of the findings is expected to be clear and self-reflective vis-à-vis the strengths and limitations of the data and study design. The fellows are closely supervised by their mentors as well as other faculty members with expertise in the specific area of investigation, in preparation of the manuscript and submission for publication in leading journals.

Graduate Courses

The fellows must take at least two university graduate-level courses. Clinical Genetics (Weill Cornell Medical College) is a five-week course focusing on current topics in medical genetics, including: basic cell biology; genetic variations; inheritance patterns (autosomal, sex-linked, mitochondrial); clinical cytogenetics; gene mapping and cloning; immunogenetics, genetics of cancer; genetic screening diagnosis; gene therapy; and genetic counseling.  Introduction to Biostatistics in Clinical Research (Weill Medical College) which covers the basic principles of research design, data analysis, and interpretation of results with an emphasis on practical statistics for medical research. Foundation for Exxcellence in Women’s Health Care – Exxcellence in Clinical Research is a six-day intensive introduction to epidemiology, research methods, and data analysis.  The content of this program has been developed following the ACGME accreditation guidelines, and is approved by American Board of Obstetrics and Gynecology. 

REI Application

Weill Cornell Medicine
Ronald O. Perelman and Claudia Cohen Center for Reproductive Medicine

1305 York Avenue, 6th Floor
New York, NY 10021 Phone: (646) 962-2764