Obstetrics Flashcards
Contraindications to TOLAC/VBAC
Prior classical or T-incision, transfundal surgery, prior rupture, history of >2 prior c-sections
*undocumented scar not a contraindication
How do you treat hyperthyroidism in pregnancy? Thyroid storm?
PTU 1st tri, methimazole 2nd/3rd tri
Storm: PTU, iodine, propanolol, steroids
Which conditions are managed w/ prophylactic lovenox during pregnancy?
Factor V homozygous, prothrombin homozygous, ATIII mutation, compound heterozygouse factor V/prothrombin, APLS, hx of prior VTE on OCPs, any prior unexplained VTE
Mneumonic/differential dx for recurrent pregnancy loss
AGE IS IT - anatomic (septate/bicorunate uterus), Genetics (aneuploidy/balanced translocation), Endocrine (hypothyroid, diabetic), Infectious (Toxo, CMV, Listeria), Social hx (smoking/alcohol/caffeine), Immunologic, Thrombophilia (APLS)
AEDs during pregnancy & management considerations
- Pregnancy increases the frequency of seizures by 30-50%
- Increased risk of IUGR, stillbirth, cleft palate, cardiac defects, neural tube defects
- Switch to single agent monotherapy (Keppra)
- Increase folate (4mg) and vitamin D supplementation
What comprises different genetic testing options and what are the sensitivity rates?
- First trimester alone (Nuchal translucency, PAPP-A, HCG) - 80% detection
- Second trimester QUAD screen (HCG, estriol, AFP, inhibin) - 80% detection
- Ultrasound alone (50%)
- Cell free DNA (98%)
- Integrated screen (96%), sequential (>90%)
Compare and contrast omphalocele and gastroschisis
Gastroschisis - R abdominal defect, sporadic inheritance, bowel contents exposed
Omphalocele - midline defect, associated w/ aneuploidy, bowel contents covered w/ sac, associated w/ other abnormalities
Varicella in pregnancy - how do you treat if exposed
When is risk of transmission to baby the highest?
Determine immunity status. If susceptible then - If asymptomatic but positive exposure, can give VZIG as prevention. If symptomatic, high risk of varicella pneumonia and mortality - admit and start IV acyclovir. Greatest risk of transmission to newborn is 5 days before and 2 days after delivery
When do you treat for GBS? How do you treat?
How do you treat if PCN allergic?
- Hx of GBS+ UTI, +GBS culture, Hx of prior infant w/ GBS sepsis or infection
- GBS unknown plus PTL, >18hr ROM, intrapartum fever
- Treat w/ PCN 5mil units, followed by 2.4mil q4hr
- Cefazolin if PCN allergic and mild risk of anaphylaxis
- Clinda if BOTH clinda and erythromycin sensitive
- Vancomycin if clinda or erythro resistant
How do you treat mastitis? What if PCN allergic OR resistant to antibiotics? MRSA positive?
Dicloxacillin 500mg four times daily x 7 days
Erythromycin if PCN allergic
Augmentin if resistant to antibiotics
Bactrim if MRSA positive but then pump and dump
Who meets the criteria for offering cell free DNA?
- Maternal age >=35yo at delivery
- Prior pregnancy with trisomy
- Abnormal maternal serum screening (1st or 2nd tri screening)
- Fetal US findings suggesting of aneuploidy risk
- Maternal or paternal balanced robertsonian translocations involving chromosome 21 or 13
What is the mechanism of action for glyburide and metformin?
Glyburide - increases insulin release from pancreatic beta cells and decreases hepatic glucose production
Metformin - increases peripheral glucose uptake by improving insulin sensitivity, decreases hepatic glucose production
What are the cut offs for the 75g 2-hour glucose tolerance test
Fasting: 100-125 impaired; >126 diabetes
2hr value: 130-199 impaired; >200 diabetes
When do you perform early 1-hr glucose test and when is it performed?
What is an alternative to performing glucose testing if patient cannot handle possible dumping syndrome?
Early testing perform if: prior hx of GDM, impaired glucose tolerance, elevated A1C, hx of prior macrosomic baby, maternal obesity, PCOS, metabolic syndrome, excessive maternal weight gain, 1st deg family hx of diabetes
-Alternative: fasting/post prandial blood sugar levels for 1-2 weeks
Which vitamin/nutrition deficiencies should be screened for in patients with hx of gastric bypass/Roux-en-Y (malabsorptive)
Vitamin D, E, A, K
Folic acid, thiamine, B12*
calcium, iron
What are the weight gain considerations for women who are underweight, normal weight, overweight, obese, and morbidly obese?
Underweight (BMI < 18.5) - 28-40lb Normal (BMI 18.5-24.9) - 25-35lb Overweight (BMI 25-29.9) - 15-25lb Obese (>30) - 11-20lb Morbidly obese (>40) - 15lb
Which fetal anomalies are associated with obesity? (list in order from high to low risk)
NTDs, cardiac defects, cleft defects, anorectal atresia, limb reduction
When should you discontinue and restart anticoagulation before/after a delivery?
Prophylactic dose - discontinue 12hr before scheduled delivery
Therapeutic dose - discontinue 24hr before scheduled delivery
Can restart heparin 4-6hr after vaginal delivery and 6-12hr after c-section
When do you test for APLS? (clinical criteria)
- Fetal death >10wk
- Three or more unexplained consecutive pregnancy losses <10wk
- Early onset severe preeclampsia/IUGR < 34wk
What is rhogam? When do you give it? How is it dosed and how long does it confer protection?
Medication to prevent Rh alloimunization. Shot of 300mcg given routinely at 28wk to Rh negative mothers. Given for other indications such as miscarriage, OB procedures (ECV, CVS, amniocentesis), abdominal trauma, ectopic pregnancy etc. Need to given within 72hr of possible exposure. Effect should last for 12wk
Congenital Toxoplasmosis
First determine if patient is susceptible (IgG/IgM). If US concerns of fetal infection, consider diagnosis by amniotic fluid PCR. Early infection has worse neonatal outcomes, late infection has higher vertical transmission rate. Rx with spiramycin for maternal infection and pyrimethamine/sulfadiazine/folinic acid for fetal infection. US signs show intra-abdominal and intra-cranial calcifications, IUGR and hydrops
Varicella in pregnancy
If mother is exposed - test susceptibility. If susceptible + exposed but asymptomatic = treat with VZIG within 96hr of exposure. If exposed and symptomatic = oral acyclovir. Give IV acyclovir if there is varicella pneummonia.
- Congenital varicella - early pregnancy infection has higher risk of malformations; highest transmission in 2nd trimester
- Neonatal varicella - highest risk of mom develops a rash 5d before or 2d after delivery (treat baby with VZIG and isolate). If baby has symptoms, give acyclovir as well.
How long should a couple wait to conceive after traveling to a Zika endemic area? When do you screen or test for Zika during pregnancy?
Women should wait 2 months, men for 3 months. Screen all women. Test women with positive exposure and symptoms OR positive exposure and concerning US findings (NAAT and IgM). NAAT should be done within a week (7 days of exposure/symptoms), if it has been >1 week then can do IgM (first 12wk of symptoms or exposure)
Which maternal infections is breast feeding acceptable and contraindicated?
Hep B and Hep C - allowed
HIV - contraindicated (up to 15% transmission risk)
When do you place an US indicated cerclage? History indicated cerclage?
When is vaginal progesterone indicated?
When is 17-OHP indicated and when?
- Hx of prior PTB < 34wk on 17-OHP with short cervix <25mm
- Prior hx of 2nd trimester loss due to cervical insufficiency; place between 13-16wk
- Exam finding of painless cervical dilation or bulging membranes in 2nd tri (rescue cerclage)
- No prior PTB with CL <20mm
- Hx of prior PTB/PPROM before 37wk, give weekly starting 16-20wk until delivery or 36wk
What are some common reasons for an elevated maternal serum AFP?
What is the gold standard for open NTD diagnosis?
What are high AFP levels associated with?
- NTD, incorrect dates, multiple gestation, abdominal wall defect, fetal demise, abnormal pregnancy/placentation (molar pregnancy)
- If acetylcholinesterase is detected on amniocentesis
- High AFP associated w/ poor pregnancy outcomes (stillbirth, oligo, PTB, IUGR, abruption)
When do you perform CVS versus amniocentesis?
CVS 10-13wk; amniocentesis >15wk
US features of accreta? When do you deliver?
Thinning of myometrium, placental lacunae/lakes, loss of normal retroplacental space, increased vascularity on Doppler, loss of uterine serosa/bladder interface
-Delivery at 34w0d-35w6d
What is the incidence and risk of recurrence of shoulder dystocia? What are the grams cut offs for offering a c-section?
Incidence 0.5-3%, recurrence 10%
Delivery not recommended if >4500g and diabetic OR >5000g and non-diabetic
Describe the Pinard maneuver, Lovset’s maneuver, and Mauriceau-Smellie-Veit maneuver
Pinard - extraction of frank breech (deliver buttocks and legs) and pull down until scapulae visible
Loveset - deliver both arms and shoulders
Mauriceau-Smellie-Veit - maintain head flexion by pressing on maxilla to deliver fetal head
What are the absolute/relative contraindications to ECV?
What factors make ECV less successful?
Breech firmly fixed in pelvis, placenta previa, prior uterine surgery, prior vertical/classical CS, extensive uterine scar
Less successful: maternal obesity, oligohydramnios, frank breech, nulliparity, anterior placenta
What do you give for seizure ppx in patients who have myasthenia gravis?
Keppra/Valproic acid OR Phenytoin OR Benzodiazepines
What is the recurrence risk for preeclampsia at term? Before 30wk? 2nd trimester?
20%, 40-50%, 65%
What are all the different kinds of twins and their relative prevalences?
Dizygotic (account for 2/3 of twins) - two separately fertilized eggs –> all of these end up di-di twins
Monozygotic (account for 1/3 of twins) - one fertilized egg that splits –> 1/3 are di-di and 1/3 are mono-di and 1/3 are mono-mono
Describe different types of monozygotic twins and when egg splitting occurs
Day 2 - di-di twins
Day 5 - monochorionic, diamniotic
Day 10 - mono-mono
Day 14 - conjoined
Describe the US findings that differentiate dichorionic and monochorionic gestations
Dichorionic - 2 placentas; thick dividing membrane, Twin Peak sign or Lamda sign
Monochorionic - 1 placenta; thin dividing membrane, T sign
When do you deliver all the different types of twins? Triplets?
Di-di by 39th week; mono-di by term; mono-mono by 34wk
Triplets by 35wk; if complications then 34wk
When is vaginal delivery allowed for face presentations? How about transverse lie presentations?
MA can PA can’t - mentum anterior OK for vaginal delivery, mentum posterior needs c-section
Transverse back up - LTCS
Transverse back DOWN - classical CS
When do you deliver for elevated dopplers and abnormal BPP? When do you deliver if all antenatal testing is normal?
Absent or reversed flow (OK if reversed). Absent deliver by 34wk, Reversed deliver by 32wk
BPP 6/10 - repeat in 24hr, lower than that needs delivery
If all normal testing, delivery IUGR < 10th by 39th week and IUGR < 5th by 37th week
What are the doses for hemabate and methergine? (how often to you give, maximum doses, side effects, contraindications)
Hemabate (PGF2alpha) - 0.25mg IM or IU every 15min for max 8 doses (causes nausea/vomiting and flushing), avoid if asthma or active cardiac/renal/hepatic disease
Methergine - 0.2mg IM/IU/PO every 2-4 hours for 24hr max (side effect nausea/vomiting), avoid if hypertensive or pre-eclampsia
*Methergine is an ergot alkaloid. Generally considered first line AFTER pitocin and fundal massage
When do you deliver the following:
Vasa previa, placenta previa, prior classical, prior rupture/uterine window, suspected accreta
Vasa previa 34-35wk
Suspected accreta 34wk
Placenta previa 36-37wk
Prior classical 36-37wk
Prior rupture/uterine window 36-37wk
Prior myomectomy 36-37wk
What are the two most common bugs which was chorio and what is the textbook treatment? What if they are PCN allergic? What is the new definition of chorio? What is the definition of isolated maternal fever?
Chorio - GBS and E. coli
Treat w/ amp and gent
Mild allergy - ancef/gent
Severe allergy - clinda/gent OR vanc/gent (depending on sensitivities)
Maternal fever with one of the following - elevated WBC, fetal tachycardia, foul smelling lochia
Fever >=100.4 which persists after 30min
*If no other explanation of isolated maternal fever, then presumptively treat w/ ampicillin and gentamicin
Which antigens are involved with alloimmunization? What is a critrical titer?
Which antigens are not clinically significant?
D, E, Fy (Duffy), K (Kell), c, Kidd
1:16 anti-D, 1:8 anti-Kell
Lewis lives, I lives
When do you treat pregnant with tamiflu?
Any exposure (Prophylaxis) - 75mg QD x 10 days, best to start ASAP
Symptomatic (Treatment): 75mg BID x 5 days
