Free USMLE Step 2 CK Obstetrics and Gynecology practice questions

Itching that begins in the late second or third trimester, is worst on the palms and soles and at night, and comes with only excoriations and no primary skin lesions is the classic presentation of intrahepatic cholestasis of pregnancy. A family history in her mother fits, because inherited variants in canalicular transporter genes predispose to it.

The diagnostic test is a serum total bile acid concentration. A level of 10 µmol/L or more in a woman with pruritus confirms the diagnosis, and the peak level also sets the delivery plan: 100 µmol/L or more calls for delivery at 36 weeks, and lower levels allow delivery between 36 and 39 weeks. Transaminases are usually mildly to moderately elevated and should be checked at the same time, but they can be normal and are not specific. Bilirubin rises little and jaundice is uncommon. Because itching can precede the rise in bile acids, testing should be repeated if the first level is normal and the itching persists. Atypical findings, such as very high transaminases, prompt a search for viral hepatitis, gallstones or preeclampsia.

A. Skin biopsy with immunofluorescence diagnoses pemphigoid gestationis, which causes urticarial plaques and blisters around the umbilicus, not itching with normal-looking skin. C. Ultrasonography evaluates gallstones, which cause postprandial right upper quadrant pain, not isolated pruritus. D. Antimitochondrial antibodies diagnose primary biliary cholangitis, considered only if liver abnormalities persist after delivery. E. Skin scraping looks for scabies mites, which produce burrows and papules in web spaces and typically affect household contacts.

This pregnant woman has classic renal colic: sudden, waxing and waning flank pain radiating toward the groin, nausea, costovertebral angle tenderness, and microscopic hematuria without signs of infection. Nephrolithiasis is the most common nonobstetric cause of abdominal pain requiring hospitalization in pregnancy.

Noncontrast helical CT is the most accurate test for stones in the general population, but in pregnancy the goal is to avoid ionizing radiation. Renal ultrasonography is the recommended first-line imaging test for suspected stones in pregnant patients (and in children), per ACR Appropriateness Criteria and ACOG guidance. It can show hydronephrosis, the stone itself in many cases, and absent ureteral jets on the affected side. Interpretation needs care because mild physiologic hydronephrosis, more often on the right, is normal in the second and third trimesters. If ultrasound is nondiagnostic, MRI without gadolinium is the next option, and low-dose CT is reserved for cases where the result would change management.

B. Noncontrast CT is the gold standard outside pregnancy, but it is not first-line here because it exposes the fetus to radiation when a radiation-free test is available. C. A KUB film exposes the fetus to radiation, misses radiolucent uric acid stones and small stones hidden by the fetal skeleton, and cannot show hydronephrosis. D. Intravenous pyelography is outdated, uses iodinated contrast, and requires multiple radiographs. E. CT urography adds contrast and multiphase radiation and is used to evaluate the urothelium for unexplained hematuria, not acute colic in pregnancy.

Blunt abdominal trauma can cause a fetomaternal hemorrhage even without bleeding or a visible abruption. In an unsensitized D-negative woman, fetal D-positive cells entering her circulation can trigger anti-D production that would endanger this and every later D-positive pregnancy. She should receive anti-D immune globulin within 72 hours of the event, and because the volume of hemorrhage after trauma is unknown and can be large, it should be quantified with a Kleihauer-Betke test (or flow cytometry). Acid elution strips adult hemoglobin from maternal cells, while fetal cells containing HbF resist and stain, allowing an estimate of the fetal blood volume. Each 300 microgram vial covers about 30 mL of fetal whole blood, so a large hemorrhage needs additional vials. A large bleed also has fetal implications (anemia, distress) and supports extended monitoring.

After the event dose, the routine 28-week dose is still considered according to timing, and another dose is given within 72 hours of delivery if the newborn is D-positive.

B. A reduced 50 microgram dose applies only to early first-trimester events, when fetal blood volume is small; at 26 weeks the standard dose is 300 micrograms and may be insufficient. C. Waiting for bleeding misses occult hemorrhage, which is common after abdominal trauma. D. Delaying prophylaxis until the routine dose risks sensitization from today's exposure, since protection should be given within 72 hours. E. A titer would only detect sensitization after it has already occurred, which is too late for prevention.

Cervical cancer screening exists to detect precancerous lesions of the cervix. This woman had a total hysterectomy (cervix removed) for a benign indication, and she has no history of CIN 2 or worse. In this situation, USPSTF, ACOG, and the American Cancer Society all recommend stopping screening; vaginal cancer is rare, and screening the vaginal cuff produces mostly false-positive results, leading to unnecessary colposcopy and anxiety without benefit. Confirming the details matters: the operative and pathology reports must show that the cervix was removed and was normal.

Exceptions in which screening continues after hysterectomy include a history of CIN 2, CIN 3, or adenocarcinoma in situ within the past 25 years (screen for 25 years after treatment, even past 65), a history of cervical cancer, in-utero DES exposure, and immunosuppression such as HIV infection. A woman who had a supracervical hysterectomy still has a cervix and continues routine age-based screening. Her other preventive care continues as usual, including screening mammography and colorectal cancer screening.

A, B, and C apply the routine age-based screening intervals for a woman with a cervix (cytology every 3 years, primary HPV or co-testing every 5 years) to a woman who no longer has one, which offers no benefit. D. Annual cuff cytology for life is not recommended even for most higher-risk patients and would generate harms from false-positive results.

Bartholin duct cysts and abscesses are common in women of reproductive age, but the glands involute after menopause, so a new Bartholin gland enlargement after age 40, especially one that is solid, firm, nontender, or persistent, raises concern for Bartholin gland carcinoma (adenocarcinoma, adenoid cystic carcinoma, or squamous cell carcinoma). These cancers are rare and are frequently misdiagnosed as cysts or abscesses, delaying treatment. The appropriate step is tissue diagnosis: biopsy or excision of the mass. If a cyst or abscess is drained in a woman over 40, the wall should still be biopsied.

If carcinoma is confirmed, management parallels other vulvar cancers, with radical local excision and inguinofemoral node evaluation, so it is important to establish the diagnosis before any definitive procedure. If the lesion is benign, excision also treats it.

B. Needle aspiration provides no tissue architecture, does not exclude carcinoma, and even for true cysts tends to recur; this mass is solid and not infected. C. Gonorrhea and chlamydia testing is reasonable for a Bartholin abscess with STI risk, but this patient has a noninflamed, solid mass and low STI risk; it would not address the main concern. D. CA-125 is a marker for epithelial ovarian cancer and is not useful for a vulvar mass. E. Expectant management with sitz baths is appropriate for a small, asymptomatic cyst in a woman under 40, not for a new solid mass in a postmenopausal woman.

Mifepristone followed by misoprostol completes about 95% to 98% of early abortions, so a few women have an ongoing (continuing) pregnancy. The clues are minimal bleeding without passage of tissue, persistent pregnancy symptoms, an hCG that has not fallen (a successful abortion lowers hCG by at least about 80% within a week), and, decisively, an ultrasound showing an embryo that has grown about a week with cardiac activity. This is why follow-up to confirm completion, by serial hCG, ultrasound, or symptoms with a urine test at about 4 weeks, is part of every medication abortion. An ongoing pregnancy is usually managed with vacuum aspiration, although a repeat dose of misoprostol is an accepted alternative; patients who consider continuing the pregnancy should be counseled that misoprostol exposure is associated with Mobius sequence and limb defects.

A. Residual hCG can keep tests positive for weeks after a complete abortion, but the level falls steadily, and the uterus would be empty rather than containing a living embryo.

B. Incomplete abortion means retained tissue without a viable embryo, usually with ongoing bleeding and a falling hCG; this embryo is alive and growing.

C. Gestational trophoblastic disease causes a disproportionately high or rising hCG with a heterogeneous intrauterine mass and no normal embryo; molar change was not seen on either scan.

D. Heterotopic pregnancy is rare without assisted reproduction, the adnexa are normal, and an ectopic pregnancy would not explain a growing intrauterine embryo.

FIGO staging of cervical cancer (2018) combines clinical examination with imaging and pathology. By size and examination alone, this 3.5 cm tumor with parametrial invasion short of the sidewall would be stage IIB. However, hydronephrosis or a nonfunctioning kidney caused by the tumor places the cancer in stage IIIB regardless of tumor size or how far the parametrial spread extends on palpation. Ureteral obstruction is presumed to reflect tumor reaching the pelvic sidewall region, and it carries a prognosis similar to sidewall disease. Here MRI shows the tumor encasing the distal left ureter with moderate hydronephrosis, so the most accurate stage is IIIB. (Pelvic or para-aortic nodal metastases would instead define IIIC1 or IIIC2.) Practically, the stage still falls within IB3 to IVA, so she will be treated with cisplatin-based chemoradiation, and she may need ureteral stenting or nephrostomy to protect renal function.

A. IB2 describes a tumor confined to the cervix, 2 to 4 cm; this tumor has parametrial invasion and hydronephrosis.

B. IIA1 describes spread to the upper two-thirds of the vagina without parametrial invasion, which she does not have.

C. IIB would be correct for parametrial invasion without sidewall extension only if there were no hydronephrosis; the tumor-related ureteral obstruction upstages her.

E. IVA requires biopsy-proven invasion of the bladder or rectal mucosa; both are uninvolved.

This 47-year-old has abnormal uterine bleeding with an irregular, heavy pattern typical of perimenopausal ovulatory dysfunction (AUB-O): anovulatory cycles without a corpus luteum leave the endometrium under unopposed estrogen, so it overgrows and sheds irregularly. The initial workup (β-hCG, TSH, CBC, and transvaginal ultrasonography) has found no structural PALM cause. Before she is treated, however, ACOG recommends endometrial sampling as the first-line test for every woman aged 45 or older with AUB, and for younger women with risk factors such as obesity, PCOS, chronic unopposed estrogen, tamoxifen use, or failed medical therapy. The same unopposed estrogen that drives anovulatory bleeding is the main cause of endometrial hyperplasia and endometrioid carcinoma, which are increasingly common in the late 40s. In a premenopausal woman, endometrial thickness on ultrasound does not reliably exclude hyperplasia or cancer; the 4-mm cutoff applies only to postmenopausal bleeding. An office endometrial biopsy is quick and accurate. If it is benign, hormonal therapy (a levonorgestrel IUD is an excellent choice) can follow; if it shows atypical hyperplasia or cancer, management changes completely.

A. A levonorgestrel IUD is an appropriate treatment once malignancy has been excluded, but placing it first would treat bleeding without a tissue diagnosis. B. Cyclic progestins likewise could mask a hyperplasia or cancer. D. Repeat ultrasonography delays diagnosis and cannot exclude hyperplasia in a premenopausal patient. E. Hysterectomy is reserved for bleeding that does not respond to medical therapy or for confirmed pathology and is not the first step.