OB/Gyn Shelf Exam Study Notes

Hey all,

So I took the Ob/Gyn shelf exam last week. I took some notes while I was studying from various sources to kind of use as a cheat sheet. These notes are from USMLEWorld, uWISE and Case Files. I figured this might help someone in the future. I can't ensure the accuracy of all the factoids on here, but I'm pretty sure they're correct. There is a lot of redundancy and little organization. I literally just wrote stuff down as I did questions. But I think this is useful still. Hopefully it will be useful to some of you as well.

• Candidal vaginitis tx is w/ clotrimazole for the patient only
• PPROM requires amniotic fluid sampling to measure fetal lung indices
• A sterile speculum should be used to avoid infection
• If premature labor occurs and the fetus has an anomaly incompatible w/ life, let the fetus be born
• All patients w/ primary amenorrhea and high FSH need to have a karyotype determination
• GBS screening occurs at 36-37 weeks. Women should be treated with penicillin G during labor, even in the absence of frank chorioamnionitis
• Semen analysis should be performed early in the evaluation of infertility
• Severe preeclampsia = pressure > 160/110
• Untreated asymptomatic bacteriuria of pregnancy can lead to pyelonephritis or cystitis. Treat with nitrofurantoin (or ampicillin or 1st gen cephalosporin) for 7 to 10 days
• OCPs are first line therapy for endometriosis in younger women desiring future fertility
• Laser treatment is appropriate if the patient is actively trying to conceive
• Hypertrophic dystrophy of the vulva is seen in postmenopausal women. Treat w/ corticosteroid topically. Biopsy is required to distinguish from vulvar carcinoma
• Behcets disease can present like herpes or syphillis w/ recurrent ulcers and uveitis.
• Fetal heart decelerations are the most common encountered anomaly. Associated with umbilical cord compression.
• HRT can actually increase the risk of coronary heart disease and stroke rather than reduce
• Luteal phase defects are treated with progesterone supplements.
• Luteal phase defect is suggest by short cycle, history of spontaneous abortions, abnormal body temp.
• Dx made by biopsy showing endometrial lag by 2+ days
• CVS can be done at 10-12 weeks
• Indicated in women over 35 y/o after an abnormal ultrasound
• Amniocentesis is done between 16-18 weeks gestation
• MSAFP is a second trimester screen
• Puerperal fever is an increase in temperature > 38C for more than 2 consecutive days in the first 10 days postpartum
• Most common etiology - endometritis
• Spiking fevers in the puerperal period that do not respond to fevers are likely due to pelvic thrombophlebitis -> give heparin
• Most common pathogens causing endometrisis in the puerperal period: anaerobes
• Endometriosis presents most frequently with dysmenorrhea, dyspareunia, and dyschezia
• The major cause of death in eclampsia is hemorrhagic stroke
• Abruptio placenta and placenta previa are the most common causes of antepartum hemorrhage
• Most common sx is bright red third trimester bleeding
• DIC is a major complication of abruptio placenta
• Risk factors for abruptio placenta are
• trauma
• maternal hypertension
• placental aburption in previous pregnancy
• short umbilical cord
• tobacco use and cocaine abuse
• folate deficiency
• Abdominal circumference is the most accurate parameter for estimating fetal weight by U/S
• Intrauterine growth restriction
• 2 types = symmetrical and asymmetrical
• Symmetrical = congenital problems prior to 28 weeks
• both head and body abnormal
• Asymmetrical = insult after 28 weeks
• Head normal body not normal
• Bilateral edema of the extremities is common in pregancy; benign. 
• Cramps and mild leg edema are very common
• Mayer-Rokitansky-Kuster-Hauseer syndrome is the result of mullerian agenesis.
• Normal secondary sex characteristics
• Amenorrhea
• Absent/rudimentary uterus
• 46 XX
• Steroids are used to enhance fetal lung maturity when premature rupture of membranes occur less than 34-weeks gestation
• Premature ovarian failure refers to failure of estrogen production by the ovaries that occur in women less than 35 years
• Autoimmune origin
• Associated with Hashimotos, Addison's type I diabetes
• Tx = egg donation
• Biophysical Profile testing = sonography + fetal heart monitoring
• NST reactivity
• Extremity tone
• Breathing movements
• Gross body movements
• Amniotic fluid volume
• Scores of 8-10 on BPP are reassuring
• Repeat BPP once or twice weekly until term for high risk pregnancies
• Non-stress test is based on tracing of fetal heart rate
• Reactive = Rise of > 15 beats/min for > 15 secs. Reassuring of fetal well being
• Nonreactive = no accelerations seen
• Oligohydramnios = AFI < 5
• Risk factors for candida vaginitis are DM, OCPs, pregnancy and immunosuppressive therapy
• Early decelerations are due to fetal head compression
• Fetal cord compression presents with variable decelerations
• Uteroplacental insufficiency presents with late decelerations
• The major source of estrogen in a menopausal women is from peripheral conversion
• Obese women have mild menopause because of peripheral estrogen production
• Pseudocyeis is an imaginary pregnancy that occurs in women with a strong desire to become pregnant
• Needs psych eval
• Primary ovarian failure = decreased estrogen and increased FSH
• FSH, more than LH, is diagnostic of primary ovarian failure
• Superpotent corticosteroid cream is the treatment of choice for lichen sclerosis
• Itchy spot in a postmenopausal woman needs a biopsy
• Distinguish vulvar carcinoma from lichen sclerosis w/ biopsy
• Intrauterine fetal demise is diagnosed with real time ultrasonogram
• IUFD is death of the fetus in utero after 20 weeks gestation and before the onset of labor
• Complete placenta previa needs C-section
• If the mother is stable and the fetus is at term, scheduled C-section is appropriate
• If the pregnancy is not at term and the mother is stable, expectant management is appropriate
• Tubo-ovarian abscesses are usually managed with triple antiobiotic therapy
• Drainage is indicated if no response after 24-48 hours
• In any woman of childbearing age with secondary amenorrhea, first rule out pregnancy with beta-hCG
• Patients with inevitable or incomplete abortions should be hospitalized and monitored to prevent complications
• For all types of abortions, RhoGAM has to be administered in all women without anti-Rh antibodies
• C-section is the only option for placenta previa
• If bleeding occurs pre-term and the mother can be stabilized and the fetus stable, conservative management at home is appropriate. Bleeding, however, must cease for a couple  days. 
• Patients with PCOS have elevated DHEA. ACTH stimulation produces exaggersted DHEA response due to increased sensitivity.
• Significant granulocytic leukocytosis may be seen in the immediate postpartum period.
• Lochia rubra is the first vagina discharge after pregnancy. It is bright red.
• In incomplete abortion, the cervix is dilated and there is incomplete evacuation of the conceptus with fragments retained in the uterine cavity
• Risk factors for abortion
• Infection
• Environmental - tobacco and alcohol
• Systemic disorders - hypothyroidism, SLE, DM
• Local maternal factors - cervical incompetence, uterine abnormalities
• Fetal factors
• RhoGaM is indicated in previously unsensitized Rh-negative women at 28 weeks gestation and within 72 hours of any procedure or incident
• Single dose azithromycin is used to treat chlamydial infection. But gonococcal infections are treated with empiric abx for both gonorrhea and chlamydia (ceftriaxone + doxycycline). 7 days of doxy can also be used for chlamydia.
• Vaginal delivery in breech position must meet the following criteria:
• fetus in frank or complete breech
• estimated fetal weight between 2500 g and 3800g
• flexed fetal head
• adequately large maternal pelvis
• no fetal or maternal indications of c-section
• experienced ob
• Pregnancy decreases the severity of peptic ulcers and multiple sclerosis
• A breast mass in a young woman requires further workup. Ask pt to return after her menstrual cycle to see if the mass has reduced in size. If so, it's likely benign.  Otherwise, proceed with US and fine needle aspiration biopsy.
• Hyperprolactinemia can be caused by hypothyroidism, which is assessed by TSH levels. 
• Increased TRH stimulates prolactin secretion
• Trichotillomania is an impulse-control disorder, characterized by compulsive hair pulling, lead to hair loss.
• Migraine and Graves disease are both lessened in pregnancy
• IUGR is birth weight below the 10th percentile
• Hypertension is a common maternal cause of IUGR
• BPP score of < 4 necessitates immediate deliver
• BPP score of 4 w/o oligohydramnios and w/ mature fetal lungs = consider delivery. If lungs not mature, give steroids and assess BPP in 24 hours
• BPP score is 6 w/o oligohydramnions -> contraction stress test. If not reassuring, deliver baby.
• Lymphogranuloma venereum presents with painless ulcer and reactive inguinal adenitis. Classic groove sign is usually seen in men.
• Hemodilution occurs in pregnancy. Maximum at 34 weeks. Nearly 40% hemodilution. Can cause anemia.
• Physiologic dyspnea of pregnancy is present in 75% of women by third trimester
• Increased minute ventilation in pregnancy causes a compensated respiratory alkalosis
• Tidal volume increases in pregnancy but not respiratory rate
• Plasma osmolality is decreased in pregnancy, increasing the susceptibility to pulmonary edema
• Increased heart rate and stroke volume causes increased cardiac output in pregnancy. 
• Total thyroid levels are increased in pregnancy
• The most common site of spread of gestational trophoblastic disease is the lungs
• Diseases in Ashkenazi jews: fanconi anemia, tay-sachs, CF and niemann-pick
• In women with poorly controlled diabetes, cardiac anomalies are the most common
• CVS done at 10-12 weeks. Does not detect neural tube defects. Does detect chromosomal and biochemical abnormalities.
• Quad Screen = inhibin A, AFP, hCG and unconjugated estriol.
• PAPP A is an effective marker for DS screening in the first trimester
• The risk of miscarriage with CVS is 1%
• Uterine rupture presents with intense abdominal pain associated with vaginal bleed. 
• Associated with hyperventilation, agitation and tachycardia
• Tx = total abdominal hysterectomy 
• Debridement and closure of the site of rupture can be considered in women with low parity who want more children
• Inevitable abortion = cervix is dilated without passage of the conceptus. 
• Presents with vaginal bleeding, lower abdominal cramps that radiate to the back and perineum, and a dilated cervix.
• In the ovulatory phase of the menstrual cycle, cervical mucus is profuse, clear and thin.
• Decreased fetal movements suggest fetal compromise. First step = non-stress test.
• Most common cause of non-reactive NST = sleeping baby; vibroacoustic stimulation is used to wake up the baby
• BPP is used after a non-reactive NST in high risk pregnancies.
• Chancre is found in primary syphilis. Painless, indurated ulceration with punched-out base and rolled edges. 
• Appears 10-60 days after inoculation. 
• Serum testing VDRL is inaccurate in primary syphilis
• Dx made via dark field microscopy 
• Renal colic in pregnancy is suggestive of nephrolithiasis. Use US to diagnose so that no radiation is used.
• suppress milk production with a tight fitting bra and ice packs
• Kallman's is a congenital absence of GnRH secretion associated with anosmia.
• Associated with hypogonadotropic hypogonadism, amenorrhea, absence of 2nd sex characteristics
• Severe pre-ecclampsia is treated with IV hydralazine, IM mag sulfate and steroids if fetus remote from term. Only if the fetus is deteriorating should it be delivered. If near term, scheduled C-section.
• Pregnancy is associated with an increase in total T4, TBG and normal TSH.
• Preterm labor should first be treated with hydration and bedrest. Works in 20% of people. 
• Tocolysis should be used if hydration fails.
• Assessment of secondary amenorrhea
• 1st - pregnancy test
• 2nd serum TSH (hypothyroidism)
• 3rd - prolactin (hyperprolactinemia)
• 4th estrogen status (progestin challenge)
• Standard dose of RhoGAM is given at 28 weeks in uncomplicated pregnancies
• No need for earlier prophylaxis
• After the events that are associated with excessive feto-maternal hemorrhage, the failure to correct the dose of anti-D immune globulin may result in maternal alloimmunization
• Post-coital emergency contraception can be given within 72 hours. 
• Pill consists of ethinyl estradiol and levonorgesterol
• Beta-2-agonists (ritodrine) may worsen edema by decreased water clearance, tachycardia
• After the first IUFD investigation of the cause should be undertaken
• 50% of the time is unknown
• Lithium is associated w/ congenital anomalies (Ebstein's). Wean off during pregnancy but don't stop cold
• Isotretinoin should be stopped immediately
• To prevent pregnancy, women should be given strict contraception when using isotretinoin
• Lupus anticoagulant is the primary cause of recurrent abortion in women with SLE
• Before 37 weeks gestation, fetuses in breech position need no intervention as they may convert to vertex automatically
• In cases of mild preeclampsia, if the pregnancy is remote from term and/or fetal lungs are not yet mature, the patient is managed with bed rest, salt-reduced diet and close observation
• Hypertensive meds are used if BP > 160/110
• Abdominal pain in a young female in the middle of her cycle w/ a benign history and clinical exam is most likely mittelschmerz
• Acute abrupt placentae include vaginal bleeding, abdominal pain, uterine contractions and uterine tenderness. 
• Retroplacental bleeding may be concealed
• Maternal hypertension is the greatest risk factor
• Anesthesia may reduce uterine activity if administered in the latent phase
• Prolactin production is stimulated by serotonin and TRH and inhibited by dopamine. Hypothyroidism may result in amenorrhea and galactorrhea
• Asymptomatic bacteriuria occurs when the urine culture grows > 10^5 CFU per ml of a single organism in an asymptomatic patient. Pyelonephritis may occur if not treated.
• Reassurance and outpatient follow up is the standard of care for threatened abortion
• Threatened abortion: any hemorrhage occurring before the 20th week of gestation with a live fetus
• Idiopathic precocious puberty is caused by premature activation of the HPO axis
• Tx: GnRH agonist to prevent premature fusion of the epiphyseal plates
• Laparoscopy is the gold standard of diagnosis for endometriosis
• Labetalol is the drug of choice to control HTN in pregnancy.
• Very effective in preventing proteinuria and diabetic nephropathy
• ACE inhibitors and ARBs are strictly contraindicated in pregnant women
• Advanced stages of premature labor should be managed more aggressively and tocolysis has to be instituted at once. Magnesium sulfate is the drug of choice for tocolysis.
• Minipill (progestin only) is the oral contraceptive of choice for the postpartum because it won't affect milk production
• IUPs should not be placed in the postpartum period before involution of the uterus
• Once the diagnosis of missed abortion is confirmed, D&C of the uterus has to be performed to avoid serious complications such as DIC and sepsis
• Dx: disappearance of the usual N/V accompanying pregnancy in first trimester, and an arrest in uterine growth
• If Dx made after 16 weeks gestation, D&C may be difficult, and artificial labor using IV oxytocin becomes more appropriate
• Routine screening test for gestational diabetes is the 1-hr 50 gram oral glucose tolerance test. 
• If glucose < 140 mg/dl after 1 hour, gestational DM is ruled out.
• If > 140 mg/dl, 3 hour OGTT is used for confirmation
• Quad screen is the most effective tool for screening for Down's in 2nd trimester
• Nuchal translucency w/ maternal serum PAPP and beta-HCG is the first trimester screen for Down
• Intrauterine growth restriction is seen in women with pre-existing diabetes and not with gestational diabetes
• Risk factors for GDM
• Shoulder dystocia
• Metabolic disturbances
• Preeclampsia
• Polyhydramnios
• Fetal macrosomia
• 4 mg of folic acid is the recommended dose for women with previous pregnancy complicated by neural tube defects
• Women with BMI > 30 should gain 11-20 lbs in pregnancy
• Organogenesis occurs in the first 8 weeks
• Methyldopa does not have associations with birth defects
• Braxton Hicks contraction are short in duration, less intense than true labor and the discomfort as being in the lower abdomen and groin.
• Labor precautions
• Contractions every five minutes for one hour
• Rupture of membranes
• Fetal movement less than 10 per two hours
• Vaginal bleeding
• Fetal scalp electrode should be placed if the heart rate cannot be confirmed using external methods
• Don't place an epidural unless fetal heart rate can be confirmed
• If an intrauterine pressure catheter is placed and a significant amount of vaginal bleeding is noted, then uterine perforation may have occurred
• Tx: with the catheter, monitor the fetus and observe signs of fetal compromise
• Most common cause of postpartum hemorrhage: uterine atony
• PPH defined as 500 cc blood loss
• s/s of depression less than 2 weeks after delivery are called postpartum blues
• self limited
• Ambivalence to the newborn helps distinguish postpartum blues from depression
• Ectopic pregnancy must be diagnosed by follow up hCG (< 50% increase in 48 hours). Then methotrexate can be used
• The discriminatory zone for beta-hCG is 2000 mIU/ml. This is the level when fetuses can be seen by US
• Ruptured ectopic pregnancy is evaluted with exploratory laparatomy
• Acute ruptured ectopic pregnancy is treated by D&C, not methotrexate
• > 25 ng/ml progesterone suggests healthy pregnancy
• 30% of pregnancies have first trimester bleeding
• D&C is indicated for a failing or ectopic pregnancy in a non-acute setting
• Methotrexate is used for ectopic pregnancy if there is hemodynamic stability, no rupture, ectopic mass < 4cm w/o heart tone or < 3.5 cm w/ heart tone, normal liver enzymes, normal white count
• S/s of ruptured ectopic pregnancy: hypovolemia, peritoneal signs, and positive pregnancy test
• Oligohydramnios is associated with IUGR
• Once IUGR is detected, weekly tests of fetal well-being are required
• BPP and NST
• Polyhydramnios does NOT complicate IUGR
• Adult complications of IUGR
• COPD
• Diabetes
• Cardiovascular disease
• Chronic hypertension
• In twin-twin transfusion syndrome, twin A (larger) is at risk for polycythemia
• Babies born to diabetic mothers are at risk for hypoglycemia, polycythemia, hyperbilirubinemia, hypocalcemia and respiratory distress.
• Sniffing is the correct position for application of positive pressure ventilation in a newborn infant. Flex neck is not necessary. Just for adults.
• The majority of first trimester spontaneous abortions is due to chromosomal abnormalities in the conceptus
• Autosomal trisomy is the most common abnormal karyotype encountered in spontaneous abortuses
• In women with insulin-dependent diabetes, the rates of spontaneous abortion and major congenital malformations are both increased.
• Provided the patient is hemodynamically stable and reliable for follow-up, expectant management is appropriate therapy for missed abortion in the first trimester
• Cervical incompetence is treated with cervical cerclage in the 2nd trimester
• first trimester surgical abortion confers no subsequent obstetric disadvantage
• The use of angiotensin converting enzyme inhibitors, such as Lisinopril, beyond the first trimester of pregnancy has been associated with oligohydramnios, fetal growth retardation and neonatal renal failure, hypotension, pulmonary hypoplasia, joint contractures and death.
• The most common cause of sepsis in pregnancy is acute pyelonephritis
• Asthma generally worsens in pregnancy
• There are no proven alternatives to penicillin therapy during pregnancy and Penicillin G is the therapy of choice to treat syphilis in pregnancy.
• Tx: Desensitization to pencillin and subsequent penicillin G therapy
• Among women with cardiac disease, patients with pulmonary hypertension are among the highest risk for mortality with pregnancy. These women have a 25-50% risk for death with pregnancy.
• Severe preeclampsia = protein > 500 mg/dL/24 hours
• Magnesium sulfate is the mainstay of therapy during labor and for 24 hours postpartum to lower the seizure threshold in preeclampsia
• A therapeutic magnesium level is between 4-7 mEq/L

• Loss of deep tendon reflexes occurs at a level of 7-10 mEq/L.
• Respiratory depression may occur at levels above 12 mEq/L.
• Cardiac arrest may occur at a level of 15 mEq/L.

• Thrombocytopenia <100,000 is a contraindication to expectant management of severe preeclampsia remote from term (<32 weeks)

• Tx: deliver must be induced immediately

• tachycardia and sinusoidal heart rate pattern are consistent with abruptio placenta
• Depoprovera can cause irregular bleeding in the first 2 to 3 months
• Genuine stress incontinence is best treated with urethroplexy
• Urethral bulking procedures are best for sphincteric insufficiency
• Use artificial sphincter as a last resort
• Oxybutynin is the best pharmacologic treatment for detrussor instability
• Central and lateral cystoceles are repaired by fixing defects in the pubocervical fascia or reattaching it to the sidewall, if separated from the white line
• Uterine prolapse is treated by vaginal hysterectomy
• Stress incontinence is caused by an increase in intra-abdominal pressure (coughing, sneezing) when the patient is in the upright position.
• urge incontinence is caused by overactivity of the detrusor muscle resulting in uninhibited contractions, which cause an increase in the bladder pressure over urethral pressure resulting in urine leakage
• Colpocleisis is a procedure where the vagina is surgically obliterated and can be performed under local anesthesia
• Pessary fitting is the least invasive intervention for prolapse
• OCPs are a first choice tx for symptomatic endometriosis
• GnRH agonists have more side effects
• Laparoscopy is used to confirm endometriosis
• Hemorrhagic cysts resolve on their own, usually
• The sudden onset of pain and nausea, as well as the presence of a cyst on ultrasound suggest ovarian torsion
• Exploratory surgery is indicated for an ovarian torsion
• A patient with a known history of endometriosis who is unable to conceive and has an otherwise negative workup for infertility, benefits from ovarian stimulation with Clomiphene Citrate, with or without intrauterine insemination.
• Asians have the highest rate of molar pregnancy
• Molar pregnancy is associated with folate deficiency
• Suction curettage is the standard management for molar pregnancies
• After suction curretage for molar pregnancy, pregnancy should be avoided in the f/u period and 6 months thereafter
• Partial moles are 69 XXY/XXX/XYY triploid and have lower risk of GTD post-molar pregnancy than complete moles
• The risk of developing another molar pregnancy is approximately 1-2%
• Complete moles usually present with larger uteri, preeclampsia and higher likelihood of developing into post-molar GTD.
• Because metastatic choriocarcinoma is quite vascular, suspicious lesions should never be biopsied.
• Quantitative beta-hCG is used to diagnosis disseminated choriocarcinoma
• The most recent consensus guidelines (2006) state that management of LGSIL (unless the woman is pregnant, postmenopausal or an adolescent) is initial colposcopic examination.
• Cervical dysplasia is best treated with LEEP
• Mammography should be offered at 50 y/o and repeated annually
• Excisional or ablative procedures are not indicated for LGSIL
• A hysterectomy with bilateral salpingo-oophorectomy is the definitive treatment for a patient with pelvic pain due to endometriosis.
• A transvaginal ultrasound would be the best way to begin a workup for an incidental finding of an adnexal mass. 
• Sinusoidal heart tracing = severe fetal anemia
• C section greatly increases the risk for endometritis
• Treat septic thrombophlebitis w heparin and abx
• anaerobes are the most common organism in endometritis
• Tx - amp/gent
• Oral amoxicillin can be used for chlamydia in a pregnant woman
•  The primary risk factor for preterm rupture of membranes is genital tract infection, especially associated with bacterial vaginosis.