REI Exam Domains 2026: Complete Guide to All 6 Content Areas

How the ABOG REI Blueprint Is Organized

Reproductive Endocrinology & Infertility is a subspecialty certified by the American Board of Obstetrics and Gynecology (ABOG). Candidates typically arrive after medical school, a four-year obstetrics and gynecology residency, and a three-year REI fellowship, a pathway described in the ASRM 2025 scope-of-practice statement. The content outline for the subspecialty exam is published as a short, four-page REI blueprint on the ABOG exam blueprints page.

That document is deliberately plain. It names six primary categories and 27 subcategories. It does not print percentage weights, and it does not state a revision or effective date, even though the file URL carries a 2026 label. That has practical consequences for how you plan: you cannot rank domains by "points available," so you have to rank them by your own weaknesses and by the clinical logic of how the topics interlock.

The six domains below follow the category structure of the current blueprint. If you want the condensed version after reading this, the REI cheat sheet compresses the highest-yield facts onto one page, and you can pressure-test each area with the REI practice tests.

Domain 1: Foundational Reproductive Endocrinology

The first category is the scientific bedrock. It has three subcategories, and the questions here tend to reward precise mechanistic knowledge rather than pattern recognition from clinic.

Why assays deserve more time than they get

Laboratory assays are easy to under-study because they feel like "lab trivia." In practice, the interpretive questions are where candidates lose points: knowing why an immunoassay result can be discordant with the clinical picture, or why a particular analyte behaves differently across platforms. Anchor each major hormone to its structure, its pharmacology, and its measurement pitfalls in one review pass, because the blueprint separates them but the exam can blend them.

Pharmacology is similarly cross-cutting. The agents you learn here (those used for ovulation induction, suppression, and stimulation) resurface in Domain 4, so a solid mechanistic foundation pays back later.

Domain 2: Reproductive Endocrine Function and Disease

This is the largest clinical-endocrinology block outside infertility itself, with five subcategories spanning physiology and pathology.

Note the lifespan framing in REI2.1. Expect the exam to ask you to reason about what is normal or abnormal at a given stage rather than recite a single adult reference range. The disorders in REI2.2 through REI2.5 reward a systematic differential: separate hypothalamic, pituitary, ovarian, adrenal, thyroid, and uterine causes before committing to a diagnosis.

Because the category pairs idiopathic with iatrogenic causes, include treatment-induced and surgery-related endocrine disruption in your review, not only primary disease.

Domain 3: Conception and Pregnancy: Physiology and Pathology

The third category follows the reproductive timeline from gametes to early gestation, with five subcategories.

Gamete biology and early embryo development are the scientific counterpart to the embryology-lab work you will see in Domain 4. If you studied them only as background during fellowship, revisit them as testable content. Endocrinology of pregnancy and early pregnancy connect hormonal physiology to clinical decisions, such as how to interpret early pregnancy findings and what the hormonal milieu implies. Recurrent pregnancy loss sits at the intersection of this domain and Domains 5 and 6, since uterine anatomy and genetic factors both feed into its evaluation.

Domain 4: Fertility and Infertility

This is the heart of the subspecialty and the category with the most subcategories on the list: five.

Do not neglect the male factor

Male infertility has its own subcategory, and candidates whose training leaned heavily female-factor sometimes under-prepare it. Know the evaluation and the treatment logic, not just the semen analysis headline.

Special considerations and ART technique

REI4.3 invites scenario-based reasoning about patients who do not fit a standard protocol. REI4.4 tests the technical side of ART. Together with REI4.5 on fertility preservation, these are the areas where an oral examiner can probe your clinical judgment, so practice explaining your reasoning aloud, not just recognizing the right option on paper.

Domain 5: Anatomic Reproductive Disorders

The fifth category has the longest subcategory list: seven structural and pelvic conditions.

These conditions share a theme: each can impair fertility or complicate pregnancy through anatomy, and each has diagnostic and therapeutic decisions that hinge on imaging and surgical judgment. Study them as a differential. When a patient presents with an abnormal cavity or distorted pelvic anatomy, you should be able to distinguish adenomyosis from leiomyomas, intrauterine adhesions from congenital anomalies, and polyps from other focal lesions, and to state how each affects conception and treatment planning.

Congenital anomalies of the reproductive tract is a subcategory that rewards classification knowledge and understanding of obstetric and reproductive consequences, so link it mentally to recurrent pregnancy loss in Domain 3.

Domain 6: Reproductive Genetics

The final category is the smallest by subcategory count, with two entries, but it is conceptually distinct.

The split between "understanding" and "application" is the useful signal. Expect questions that move from the principle of a test to a patient-level decision: whom to test, which test fits the question, and how to counsel on the result. Because genetics touches embryo evaluation, pregnancy loss, and gonadal dysfunction, it reinforces material in Domains 2, 3, and 4 rather than standing alone.

One Blueprint, Two Exams: QE and CE

The REI credential retains both a written Qualifying Examination (QE), delivered through Pearson VUE, and an oral Certifying Examination (CE). The six-domain blueprint is a common document: it does not assign separate coverage or weights to each stage. The two exams remain distinct in format even though they draw from one content outline.

That last row matters. Numeric details such as fees and registration windows are not set by the common blueprint, so verify them against the current bulletin for the stage you are sitting. For eligibility specifics, see REI requirements; for the money side, see REI certification cost; and for timing, see REI exam dates. An ABOG presentation to fellowship program directors listed 2026 dates of July 20 for the subspecialty QE and April 13-17 for the CE, but those are historical 2026 dates, not an offer of upcoming booking windows.

Sequencing Your Review Around the Domains

You do not need a generic study system here; you need an order that respects how these domains depend on each other. Foundations come first because pharmacology and assay interpretation recur throughout. Clinical endocrinology and pregnancy physiology come next because they feed the infertility and anatomic material. Genetics is best placed last, once you have the clinical scenarios it applies to.

Adjust the pacing to your own gaps; the point is the dependency order, not the calendar. For a fuller plan, see the REI study guide, and test yourself by domain with the practice question bank.

If you are weighing the bigger picture, our guides on whether REI certification is worth it and the REI salary guide cover the career side, and this domain guide is the reference to return to as you map your progress.

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