top of page

NBME OBGYN Form 3 - Answers & Explanations

Updated: Feb 25, 2020

1) Ectopic pregnancy

• ↑ β-hCH + abdominal pain + no gestational sac = ectopic pregnancy

• Ectopic pregnancies have a lower β-hCG than expected and don’t double every 24 hours

• This patient has a pseudo-gestational sac (present in ~10% of ectopic pregnancies)

2) Antenatal testing • Antenatal testing will explain why there is polyhydramnios

• Amniocentesis → ↑ risk of PROM

3) No longer indicated • Total abdominal hysterectomy (TAH) in a patient with no prior history of cervical dysplasia (further pap testing not needed because the TAH was due to a benign cause)

• Total abdominal hysterectomy includes removal of the cervix → stop pap testing (no cervix, no cancer) • A partial/supracervical hysterectomy would entail removal of the uterus with preservation fo the cervix

4) Placement of a copper IUD • Hormonal contraception should be avoided in women with current or past history of breast cancer

5) Insulin

• Maternal hyperglycemia → ↑ fetal insulin production → ↓ surfactant synthesis → ARDS (hyaline membranes)

• Cortisol & thyroxine → ↑ surfactant synthesis

6) Granulosa cell tumor

• Granulosa cells convert testosterone to estradiol via aromatase

• Malignant proliferation → ↑ estradiol levels → postmenopausal thickened endometrium

7) Injury to the fifth and sixth cervical roots • Erb-Duchenne palsy → pronated forearm, adducted, internally rotated shoulder • Klumpke palsy (injury to lower trunk, C8-T1) → total claw hand, Horner syndrome

• Spontaneously resolves within 3 months

8) Secretory endometrium • Progesterone, which is normally secreted by the corpus lute during ovulatory cycles, causes differentiation of the proliferative endometrium into secretory endometrium; withdrawal causes menstruation

9) Clomiphene

• Clomiphene treats infertility due to anovulation

• Clomiphene blocks estrogen receptors at the hypothalamus, inhibiting negative feedback mechanism and restoring pulsatile release of GnRH

• Clomiphene is associated with twins and ovarian hyper-stimulation

10) Parvovirus B19 infection • Polyhydramnios, ascites, and skin thickening are consistent with hydrops fetalis

(cardiac inability to keep up with the anemia induced by Parvo)

• Work in a preschool → obtain infection from children

11) Cocaine use • Cocaine → placental abruption

• Cocaine is a more significant risk factor than amphetamine or tobacco use

12) Estrogen deficiency • This patient has urge incontinence, a urinary sxs of atrophic vaginitis (menopause)

13) Normal development • Weight and height is normal, amenorrhea < 6 months

14) Intrahepatic cholestasis • Typically presents in the 3rd trimester with pruritis that is worse on hands/feet

• Dx: ↑ total bile acids (> 10) • Tx: Ursodeoxycholic acid + delivery at 37 weeks gestation

15) Incompetent cervix • Breech position “in the vagina” (not uterus) = fetus is descending, likely due to an incompetent cervix • No contractions rule out all labor options

16) Voiding immediately after coitus • Early postcoital voiding reduces risk of UTI

17) Karyotype analysis • Absent thelarche + ↑ FSH = primary hypogonadism, likely due to Turner syndrome

18) Cervical stenosis

• 2° dysmenorrhea or amenorrhea s/p cervical procedure = development of surgical stenosis (eg, this patients “small, scarred cervical os”)

• Unable to expel sloughed off layer → build up & possible retrograde menstruation → ↑ risk of endometriosis

19) Uterine rupture • Previous cesarean section + fetal parts above the fundus

20) Cyclic progesterone therapy • This adolescent has irregular menstrual bleeding due to anovulatory cycles • Progesterone, which is normally secreted by the corpus lute during ovulatory cycles, causes differentiation of the proliferative endometrium into secretory endometrium; withdrawal causes menstruation

21) Galactocele • Mobile, well-circumscribed, non-tender mass with no fever

• Mastitis = tenderness + erythema + fever • Abscess = tenderness + erythema + fever + fluctuant mass

22) Ultrasonography of the pelvis

• With 6cm dilation, presenting fetal part should be palpable

• U/S should be used to check for CPD (cephalopelvic disproportion), transverse fetal lie, etc.

• Performing an amniotomy prior to head engagement can cause cord prolapse

23) Premature labor • ~60% of twin are delivered preterm; ~90% of triplets are delivered preterm

24) Bartholin duct abscess

• Common in women age ≤ 30

• Bartholin ducts are located B/L at the posterior vaginal introitus and have ducts that drain into the vulvar vestibule at the 4 and 8 o’clock positions to provide vulvuvaginal lubrication

• Tx (symptomatic): I&D followed by a Word catheter placement

• Tx (asymptomatic): observation - spontaneous drainage and resolution may occur

25) Maternal fever • Fetal tachycardia (>160/min) is commonly associated with maternal fever • Cardiotocography (CTG) shows fetal tachycardia with minimal to moderate variability

26) Herpes simplex virus 1 • HSV and H. ducreyi are the two most common causes of tender genital lesions • Clusters of small round lesions and remnants of vesicle clusters are visible • This patient has had “increasing stress during the past month” = herpes outbreak

27) Measurement of urinary ketones

• Hyperemesis gravidarum (HG) is differentiated from typical vomiting of pregnancy by the presence of ketones on urinalysis or lab abnormalities (eg, hypokalemia, hypochloremic metabolic alkalosis)

• Tx: admission to hospital, antiemetics + IVF

28) Squamous cell carcinoma • Squamous cell carcinoma is the most common type of cervical carcinoma (~80%)

• Smoking and HPV 16, 18, 31, and 33 are the most significant risk factors • Usually presents in women > 60

29) Fibrocystic changes of the breast • Fibrocystic change = multiple, tender • Fibroadenoma = single, non-tender mass

30) Endometrial biopsy

• This obese patient (BMI 37) is having heavy menstrual flow, likely from ↑ estrogen (aromatase conversion in excess adipose tissue)

• Any woman ≥ 45 with abnormal uterine bleeding (AUB) → endometrial biopsy

• Any woman ≥ 35 with atypical glandular cells on Pap → endometrial biopsy

31) Parvovirus B19 • Polyhydramnios, ascites, and skin thickening are consistent with hydrops fetalis (cardiac inability to keep up with the anemia induced by Parvo)

32) Amniotic fluid embolism • Present with rapid onset of hypoxemic respiratory failure, severe hypotension, and DIC during labor or the immediate postpartum period • Tissue factor in amniotic fluid activates the coagulation cascade

33) Folic acid deficiency • No prenatal care in an alcoholic with macrocytic anemia • B12 deficiency would have neurological sxs • Pregnancy → ↑ plasma volume → dilution of WBC and platelet concentrations

34) Polymicrobial infection

• Fetal tachycardia + maternal fever + prolonged rupture of membranes = Chorioamnionitis

• Ampicillin & gentamicin are the correct antibiotics, but they were only given 8 hours ago and have not had enough time to impact maternal fever

• Septic pelvic thrombophlebitis is a diagnosis of exclusion which requires persistent fever unresponsive to antibiotics and a ⊖ infectivity workup

35) Alendronate now

• Bisphosphonates are the drug of choice for prevention and treatment of steroid induced osteoporosis

• SLE is a relative contraindication for estrogen use due to ↑ risk of VTE/stroke

• Additionally, this woman is premenopausal and has normal ovarian function (she has enough estrogen)

• Raloxifene is not given to premenopausal women

36) Urethrocele

• ⊕ Q-tip test = stress incontinence; >30° of movement = urethral hypermobility

• Well supported anterior and posterior vaginal wall rules out cystocele and rectocele

37) Imperforate hymen • This adolescent girl likely has an imperforate hymen - amenorrhea and cyclic lower abdominal pain with an anterior central mass (hematocolpos)

38) Pregnancy test • Ruling out pregnancy is the most appropriate next step in diagnosis

39) Surgical exploration

• Fever + leukocytosis + right-sided abdominal pain → appendicitis

• Appendix perforation → fluid in paracolic gutter (which could potentially cause peritonitis/sepsis)

40) Administer a prostaglandin • Late- and post-term pregnancies are commonly complicated by oligo-hydramnios

• Aging placentas may have decreased fetal perfusion, which causes decreased renal perfusion and urinary output

• The presence of oligohydramnios is an indication for delivery • Cervix is not favorable yet, so ripen cervix with prostaglandin

41) Necrotizing fasciitis

• Bartholinitis (cellulitis) is a painful complication of Bartholin cysts, and more commonly, Bartholin abscesses

• Necrotizing fasciitis of the perineum (Fournier’s gangrene) is a severe complication of Bartholinitis associated with diabetics

42) Hydatidiform mole • Hydatidiform mole → ↑↑↑ β-hCG → ovarian hyper-stimulation → theca lutein cysts (resolve with decreasing β-hCG levels)

43) Indirect antiglobulin (Coombs) test

• Rh ⊖ mother in her 2nd pregnancy

• Indirect Coombs test detects presence of unbound antibodies in the serum (direct Coombs test detects antibodies attached directly to the RBC surface)

• Kleihauer-Betke test is used to check the dose of RhoD

44) Doppler ultrasonography of the umbilical artery • This baby has asymmetrical FGR • Doppler U/S of the umbilical artery can show absent or reverse flow, and determines the risk of IUFD

45) Cone biopsy of the cervix • This patients SCJ cannot be visualized meaning inadequate colposcopy result

• Non-pregnant women > 25 with CIN3 should be managed with LEEP or Cone biopsy of the cervix

• Pregnant patients should be managed with colposcopy + biopsy to confirm CIN3 (need to be sure before making a pregnant patient incompetent or stenosed)

46) Follicle-stimulating hormone

• ↑↑ FSH is specific for menopause (loss of negative feedback on FSH due to ↓ estrogen)

• Hypothyroidism can’t account for night sweats, anxiety, etc.

47) Test for Chlamydia trachomatis • All sexually active females < 25 should be offered annual Chlamydia and Gonorrhea screening

48) Autoimmune ovarian failure

• This patient has primary ovarian insufficiency, hypergonadotrophic hypogonadism (↑ FSH & ↓ Estrogen), in the setting of autoimmune disease

49) Ultrasonography • U/S is the next best step to exclude the possibility of incorrect dating • ↑ MSAFP is seen in multiple gestations, placental abruption, fetal abnormalities, or error in the date of gestation

50) Candida albicans • Candida vaginitis presents with a normal pH (3.8 - 4.5) ± thick ‘cottage cheese’ discharge • Risk factors: recent corticosteroid or antibiotic use, pregnancy, diabetes

Found a mistake or have a suggestion? Let us know here


Recent Posts

See All

NBME Medicine Form 6 - Answers & Explanations

Author: Sagie Haziza & Gennadiy Guralnik Editor: Jordan Abrams 1) Abnormal red blood cell membrane • Hereditary spherocytosis: jaundice, anemia, high-normal MHCH, loss of central pallor • ⊖ Direct Coo

NBME OBGYN Form 6 - Answers & Explanations

Authors: Luke Carlson Editor: Miriam Andrusier 1) Mixed enteric and skin flora • Bartholin cyst gland abscess – mixed enteric and skin flora 2) Puerperal sepsis • Patient is demonstrating signs and sy

NBME Medicine Form 5 - Answers & Explanations

Editor: Jordan Abrams 1) Valvular insufficiency of deep veins ● Mild edema due to incompetent valves + varicose veins due to saphenous vein reflux + area of hyperpigmentation (stasis dermatitis) over


Jordan Abrams
Jordan Abrams
Feb 25, 2020

@gaba thank you for your excellent feedback and explanation!


Just an FYI re number 3. "Total abdominal hysterectomy includes removal of the cervix → stop pap testing (no cervix, no cancer)" a total abdominal hysterectomy itself isn't the reason why you stop pap testing. The patient did not have any history of cervical dysplasia/cancer and therefore after TAH for a benign cause (fibroids) does not need further pap testing. If the TAH were for cervical dysplasia, she would need yearly pap testing of the vaginal cuff because vaginal cancer may still occur

bottom of page