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He helped me make a plan, pass on my first attempt, got me then through all my clinical rotations to pass my Shelf exams on the first try, got me a good Step 2 score
Tim S.
The OB/GYN shelf is the NBME Obstetrics and Gynecology Subject Exam, 110 questions in 2 hours 45 minutes. Its outline is unusual: two systems make up almost all of it. Pregnancy, childbirth and the puerperium is 40–45%, and the female reproductive system and breast is another 40–45%.
That concentration is good news. The content is narrow and deep, so focused studying moves your score quickly, especially on prenatal care, complications of pregnancy and gynecologic screening.
Exam format at a glance
| Topic | Official rule | Source |
|---|---|---|
| Length | 2 hours 45 minutes, plus a 15-minute tutorial on web exams. | NBME: subject exam timing chart |
| Questions | 110; exams may include unscored field-test questions. | NBME: subject exam timing chart |
| Scoring | Equated percent correct (EPC) on a 0-100 scale, representing the percentage of content mastered. | NBME: Subject Exam Program Guide |
| Passing score | None set by NBME. NBME Grading Guidelines help clerkship directors set passing and honors grades; schools decide. | NBME: Subject Exam Program Guide |
| Who gives it | Schools: the exams are available for purchase by medical school faculty only. | NBME: subject exam questions for educators |
| Fee (paid by the school) | $52 at school, $54 remote, $106 at Prometric, July 1, 2026 to June 30, 2027. | NBME: subject exam fees |
| Results | Often posted to schools the calendar day after the testing window ends, up to three business days; examinees see results in INSIGHTS. | NBME: Subject Exam Program Guide |
What OB/GYN shelf questions look like
Obstetric questions usually give a gestational age and a complaint, such as bleeding at a certain week or high blood pressure late in pregnancy, and ask for the diagnosis or the safest next step for both patients. Gynecology questions often begin with a screening result or abnormal bleeding and ask what comes next.
Drug and screening questions are common. A medicine that is first-line outside pregnancy may be the wrong answer inside it, and a screening question often depends on age and history more than symptoms.
What the OB/GYN shelf covers
NBME's Obstetrics and Gynecology outline is the source of these ranges. See the outline.
| By system | Share of exam |
|---|---|
| Pregnancy, childbirth and the puerperium | 40–45% |
| Female reproductive system and breast | 40–45% |
| Other systems, including multisystem disorders | 5–10% |
| General principles, endocrine system | 1–5% each |
| Social sciences: communication, ethics and jurisprudence | 1–5% |
| By physician task | Share of exam |
|---|---|
| Diagnosis: history, exam, diagnostic studies, outcomes | 45–50% |
| Pharmacotherapy, intervention and management | 20–25% |
| Health maintenance, prevention and surveillance | 13–17% |
| Applying foundational science concepts | 8–12% |
Under pregnancy NBME lists preconception counseling, prenatal risk assessment, supervision of normal pregnancy, obstetric complications, labor and delivery, the puerperium, the newborn to four weeks, adverse effects of drugs on pregnancy and systemic disease in pregnancy. Under gynecology it lists normal female function, breast disorders and neoplasms, infections, cancers of the cervix, ovary, uterus, vagina and vulva, fertility and infertility, menopause, menstrual and endocrine disorders, sexual dysfunction, and traumatic and congenital disorders. By site of care the exam is ambulatory 70–75%, inpatient 15–20% and emergency department 5–10%.
High-yield areas on the OB/GYN shelf
- Prenatal care: what is checked at each stage of pregnancy and why.
- Hypertensive disorders of pregnancy and gestational diabetes.
- Bleeding in pregnancy: ectopic pregnancy, miscarriage, placenta previa and placental abruption.
- Labor and delivery: the stages of labor, fetal heart rate tracings and postpartum hemorrhage.
- Drugs in pregnancy: NBME lists adverse drug effects on pregnancy as its own subtopic.
- Gynecologic screening: cervical and breast cancer screening and the work-up of abnormal results.
- Abnormal uterine bleeding, contraception, infertility and menopause.
- Sexually transmitted infections and pelvic inflammatory disease.
A closer look at prenatal care and screening
Prenatal care. NBME lists preconception counseling, prenatal risk assessment and supervision of normal pregnancy as separate subtopics. Questions in this area reward knowing what happens at each stage of pregnancy and why it is done then.
Screening. With health maintenance, prevention and surveillance at 13–17%, screening is a steady source of points. Build a single table of who is screened for what and how often, and check it against current USPSTF recommendations.
Common mistakes on the OB/GYN shelf
- Skipping the pregnancy test. In any person who could be pregnant, it is often the first step.
- Mixing up screening intervals and ages for cervical and breast cancer.
- Choosing a drug that is unsafe in pregnancy because the question never says "pregnant" in the first line.
- Reading fetal heart rate tracings by memorised pattern instead of asking what the tracing means for the baby.
- Under-studying health maintenance, which NBME gives its own 13–17% task category on this exam.
Test-day tips for the OB/GYN shelf
- Note the gestational age or the patient's age and history first.
- Ask whether the patient could be pregnant before choosing a test or drug.
- For tracings, decide what the pattern means for the baby, then choose the action.
- For screening, match the test to age and risk, not to symptoms.
OB/GYN shelf scores and percentiles
NBME reports the OB/GYN shelf as an equated percent correct (EPC) score on a 0 to 100 scale, meant to show the share of the content you have mastered (NBME Subject Exam Program Guide). There is no NBME passing score. NBME publishes grading guidelines to help clerkship directors set passing and honors cut-offs, and each school decides its own (NBME Program Guide).
That is why the same score can be an honors grade at one school and a pass at another. Ask your clerkship coordinator for your school’s cut-offs in the first week, and read percentile charts as context rather than as your grade. Our shelf percentiles guide explains how EPC scores and national percentiles relate across the shelves.
Results are usually posted to your school the day after its testing window closes, and can take up to three business days; you then see your report in NBME’s INSIGHTS dashboard (NBME Program Guide).
How to score well on the OB/GYN shelf
Because two systems make up most of the exam, the highest-yield move is an honest split of your misses between obstetrics and gynecology every week, then giving the weaker half more of the next week. Health maintenance carries its own 13–17% of the exam (NBME outline), so a screening table you rebuild from memory twice a week is worth more than another pass through a review book.
For scored practice, NBME’s Clinical Science Mastery Series has OB/GYN forms of 50 questions for $21, and the score report includes a table that converts your result to the approximate subject exam scale (NBME Clinical Science Mastery Series). Take one early to find the weak half, and one about a week before the shelf to confirm it has moved. If the two forms disagree with your question bank, trust the NBME forms: they are written to the same outline as the exam you will sit.
How to study for the OB/GYN shelf during the rotation
Most OB/GYN rotations split time between labor and delivery, the operating room and clinic. We match the reading to the block you are on: labor, delivery and postpartum topics on L&D weeks, gynecologic surgery and oncology on the GYN weeks, and screening, contraception and prenatal care in clinic.
Since nearly three-quarters of the exam is set in clinic, we make sure outpatient gynecology and prenatal care are covered early, even if your rotation started on labor and delivery. The last stretch is timed mixed blocks and practice forms.
A sample week of OB/GYN shelf prep with us
- Labor and delivery block: stages of labor, fetal heart rate tracings, postpartum hemorrhage and hypertensive emergencies.
- Gynecology block: pelvic masses, gynecologic cancers and surgical complications.
- Clinic block: prenatal visits, screening, contraception and menopause.
- Weekly review: misses sorted into obstetrics or gynecology so the weaker half gets the extra time.
After each OB/GYN practice form, ask
- Were my misses mostly obstetrics or mostly gynecology?
- Did I pick a drug that is unsafe in pregnancy?
- Did I get the screening age or interval wrong?
- Could I explain what each fetal heart rate tracing meant?
- Did I check for pregnancy first when it mattered?
Where the OB/GYN shelf leads
Pregnancy and gynecology questions return on Step 2 CK and COMLEX Level 2-CE. NBOME's Level 2-CE blueprint sets the genitourinary/renal system and breasts at a minimum of 5% and human development, reproduction and sexuality at a minimum of 5%.
Just as useful is the reflex this rotation builds: asking whether a patient could be pregnant before choosing a test or a drug. That question changes answers across many specialties.
Study resources for the OB/GYN shelf
Practice forms for this exam come from NBME's Clinical Science Mastery Series: 50 questions per form for $21, timed or self-paced. We split the review of each form into obstetrics and gynecology, since the outline weights them almost equally.
The professional standard behind most answers is the American College of Obstetricians and Gynecologists' practice bulletins, and screening questions follow the US Preventive Services Task Force recommendations. Add a question bank and an Anki deck for screening schedules and drugs in pregnancy.
Who tutors the OB/GYN shelf
OB/GYN prep with us is led by Dr. Shauhin “Sean” Moazezi, DO with the team. The approach is the same one our reviews describe on the other shelves: a plan around your rotation and a question method that holds up under time pressure.