Obstetrics 7

  1. When should you start antepartum fetal monitoring?
    After the viability of fetus – alveoli are formed after 24 weeks, and thus, after 24 weeks, we can monitor the fetal wellbeing.
  2. What  are the ultrasound parameters for monitoring fetal growth?  [AI 04]
    • Fetal crown rump length
    • Biparietal diameter 
    • Head circumference
    • Abdominal circumference
    • Femur length
    • Total intrauterine volume
  3. What test do you do if mother says there is decreased fetal movement? What test for No fetal movement?
    • Decreased Fetal movement – NST
    • No fetal movement – Sonogram
  4. What should be the normal rate and duration of the acceleration when the fetus moves?
    • Increased HR ≥ 15beats/min and lasting for ≥ 15 sec.
    • Image Upload 1
  5. What is reactive NST? [AIIMS 2003]
    • Reactive NST is ≥2 accelerations in 20 minutes.
    • If there is reactive NST, the chance of fetal death in next 7 days is 3/1000.
  6. What is non reactive NST?
    • It is <2 accelerations in 20 minutes.
    • If there is non reactive NST, 80% are false NR rates, it is because the fetus is sleeping.
    • But if the fetus is under effect of drug or medication, or if the fetus has any CNS anomaly, then, there is negative NST.
  7. What do you do if you find Non reactive NST?
    Vibroacoustic stimulation – it gives a sound wave and vibrates – so that if the fetus is asleep, it wakes up.
  8. What do you do if the NST is non reactive even after vibroacoustic stimulation.?
    • We do Biophysical profile.
    • Contraction stress test can be done but it is much costly and more time consuming.
  9. Where is the amniotic fluid made in gestation?
    • In first half (<16 weeks) - from fetal membranes -- amnion and chorion
    • In second half (> 16 weeks) -  kidney is the major source of amniotic fluid. [AIIMS 98, MAHE 01, SGPGI 02]
  10. Which fetal organ needs amniotic fluid for its maturation?
    • Lungs - the fetus aspirates the amniotic fluid that helps the lungs for its maturation.
    • So, in case of oligohydraminos, there is pulmonary hypoplasia .
  11. What is normal AFI?
    • Normal – 9-25cm
    • Borderline – 5-8 cm
    • Polyhydraminos >25 cm
    • Oligohydraminos < 5cm
  12. What are the important causes of oligohydraminos?
    • Bilateral renal agenesis
    • Posterior urethral valves [SGPGI 03] 
    • Drugs like PG inhibitors, ACE inhibitors
    • IUGR associated with placental insufficiency
    • Postmaturity [IOM 07]
  13. What are the important causes of Polyhydraminos? [AIIMS 03]
    • Anencephaly 
    • Open spina bifida
    • Esophageal or duodenal atresia
    • Facial clefts [AI 10] and neck mass
    • Multiple pregnancy
    • Maternal diabetes
  14. Congenital malformation that can be detected earliest on USG: [AI 94]

    D. Anencephaly

    Obstetric ultrasonography performed in the 1st trimester of pregnancy can detect a fetus without a brain (anencephaly)
  15. Why is there polyhydraminos in Anencephaly, spina bifida?
    In anencephaly, There is defect in swallowing reflex – so the fetus cannot swallow the amniotic fluid.

    In spina bifida, excess amounts of fluid are thought to be caused by increased fluid coming from the exposed spinal cord or by excess urination caused by overstimulation of the exposed spinal cord.
  16. How do you manage a case of hydraminos  with marked maternal distress?
    • < 37 weeks - Amnioreduction [AI 04] 
    • >37 weeks - Amnioreduction, stabilising oxytocin drip, ARM.
  17. Why is there external malformation in oligohydraminos ?
    It is because of compression of the baby leading to flattened nose, talipes equinovarus, recessed chin, low set ears.
  18. What are the components of Biophysical Profile?
    • Movement of foetal body
    • Breathing  movements of fetus
    • Tone of the foetus
    • CTG monitoring of foetal heart rate (Non-stress test)
    • Volume of amniotic fluid (Amniotic fluid index)

    [@ Bio-physical profile has 2 components - Bio-logical related to living or not (heart rate and breathing movements) and  Physical related  to movements (movement, tone, and space for movement (amniotic fluid)]
  19. How do you manage a fetus with different BPP scores?
    • 8,10 - Reassuring, repeat SOS 
    • 4,6 - Deliver, or repeat BPP or Contraction stress test
    • 0,2 – prompt delivery
  20. What are the components of Modified BPP?
    • 2 components:
    • 1. Non stress test - best indicator of current placental function
    • 2. Amniotic fluid volume - best indicator of long term placental function
  21. What happens to the intervillous blood flow as the contraction increases?
    As the contraction increases, the intervillous blood flow decreases, and at 40mmHg, the intervillous blood flow stops.
  22. What is the principle of Contraction stress test?
    The test is based on decreased intervillous flow during contractions. During uterine contractions, there is decreased flow of the blood in the intervillous space. We are going to assess the fetus during this contraction phase if the fetus can adjust this contraction to maintain its heart rate and prevent falling of the heart rate. So, we are stressing the fetus by decreasing the blood flow. We measure the fetal heart rate and contractions of uterus and ascess the result.
  23. What should be the minimum contraction of uterus to make contraction stress test?
    ≥3 contractions in 10 minutes
  24. What is negative and positive contraction stress test?
    Negative CST - If there are no late decelerations, it is called as negative CST. Negative CST is good. If late decelerations are absent, then, fetal deaths in following week is 1/1000. IT SIGNIFIES THAT INTERVILLOUS BLOOD FLOW IS OK.

    Positive CST – if there are repetitive late decelerations, it is called as positive CST. Positive CST is bad. There should be gradual increase or decrease in FHR and delayed relative to uterine contractions.
  25. How do you manage a case according to the CST results?
    • Negative CST – absent late decelerations with ≥3 UC in 10 minutes – reassuring, repeat as indicated.
    • Positive CST - ≥ 50% late decelerations with ≥ 3 UC’s in 10 minutes - may die in utero - deliver promptly.
  26. What is the most common indication of CST?
    BPP of 4 or 6.
  27. What is the condition of the baby?Image Upload 2
    • NST component- Fetal movement
    • CST component - intervillous blood flow

    • Contractions +, no late decelerations - Negative CST., 
    • Accelerations+ -  positive NST. 
    • Baby is  OK for two reasons - there is adequete intervillous flow and the baby is moving well.
    • Image Upload 3
  28. How do you evaluate this strip? Image Upload 4Image Upload 5
  29. How do you evaluate this strip? Image Upload 6
    Image Upload 7
  30. What is the principle of Umbilical artery Doppler?
    What is Umbilical Artery Doppler?
    • Umbilical artery Doppler can be used to determine blood flow across the umbilical artery. 
    • This is specially important in pregnancies complicated by fetal growth restriction (IUGR). 
    • The Umbilical artery normally has a foreward flow throughout the cardiac cycle. 
    • Absent or Reversed flow signifies increasing impedence to umbilical artery blood flow. 
    • This is seen in extreme cases of fetal growth restriction and result from poorly vascularized placental villi. 
    • Reversed end diastolic flow carries a worse prognosis [AI 07]  (mortality 33%) in comparison to absent end diastolic flow (mortality 10%). 

    Image Upload 8
  31. What is the indication of Umbilical artery Doppler?
    The only indication of Umbilical artery Doppler is IUGR Fetus
  32. What is normal fetal heart rate? What is fetal bradycardia and tachycardia? 
    • Normal heart rate – 110-160beats/min
    • Tachycardia  >160
    • Bradycardia <110 {it is  to be noted that change in fetal heart rate is not necessary that the fetus is  in trouble]
  33. What maternal mediations cause fetal bradycardia? 
    • Beta-blockers 
    • Local anesthetics 
  34. What maternal medications causes fetal tachycardia?
    • Beta-agonists 
    • Parasympatholytics
  35. What maternal medications cause decreased variability of fetal heart rate?
    If the fetal heart is not variable and is almost constant, it is not the good sign. Variability is because of sympathetic and parasympathetic Nervous system Interplay. 

    • Corticosteroids and Betamethasone decrease variability of fetal heart rate. 
    • Image Upload 9
  36. What are the causes of Early, Variable and late decelerations?
    • Variable deceleration —Cord compression [UP 01, AIIMS 03]
    • Early deceleration      —Head compression
    • Acceleration              —Okay!
    • Late deceleration       —Poor uteroplacental perfusion

    [@ VEAL CHOP, veal is meat from calf] 

    • Early decelerations   –  can ignore  
    • Variable decelerations –  worry  only if severe 
    • Late decelerations –  always worry.
    • Image Upload 10
  37. What is reassuring FHR pattern?
    • Baseline rate normal 
    • Accelerations present 
    • Decelerations absent 
    • Variability present
  38. What is Non-reassuring FHR Pattern?
    • Baseline – tachy or brady
    • Severe variable decelerations 
    • Any late decelerations 
    • Absent variability 

    [The term FETAL DISTRESS is imprecise and non-specific, Use NONREASSURING FETAL STATUS  followed by a description of the findings]
  39. What are the  measures of Intrauterine Resuscitation?
    • Decrease uterine contractions – discontinue oxytocin, give terbutaline 
    • Increase IV volume – 500ml rapid IV bolus
    • High flow oxygen  -  8-10 litres by face mask 
    • Change position – left lateral position 
    • Vaginal exam – rule out prolapsed cord 
    • Scalp stimulation – look for accelerations  [stimulate the scalp of the fetus, it is similar to vibroacoustic stimulations]
  40. What is the normal fetal blood pH? 
    • ≥ 7.20 (reassuring) 
    • If fetal pH is <7.2, most of the time, we must do C/S. 
  41. How do you mange Non-reassuring Electrical Fetal monitoring patterns?
    • Examine EFM strip carefully
    • Confirm abnormal findings
    • Identify non-hypoxic causes 
    • Initiate Intrauterine resuscitation 
    • By this procedure also, if the tracing does not normalize,  Prepare for delivery:
    • - If in first stage of labor -- emergency C/S,  
    • - If in second stage --  Vacuum/Forceps or emergency C/S
Card Set
Obstetrics 7