Obstetrics: CTGs & USS Flashcards

1
Q

elements of biophysical profile

A

1) Nonstress test (CTG)
2) fetal breathing movements
3) Fetal tone
4) amniotic fluid volume
5) fetal movements

0 or 2 points allocated per element

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2
Q

BPP scoring - what is a normal result?

A

10/10 ; 8/8 if NST not done, 8/10 +2 for amniotic fluid

1/1000 perinatal mortality within 1/52 without intervention

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3
Q

BPP scoring - a normal result as a risk of fetal death of?

A

0.4-0.6/1000

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4
Q

BPP scoring - what is an equivocal result?

A

6/10 + 2 (amniotic fluid)

Significant possibility of developing asphyxia cannot be excluded

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5
Q

BPP scoring - management for an equivocal result?

A

Repeat within 24h, or expedite delivery if near term (>34/40)

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6
Q

BPP scoring - what is an abnormal result?

A

6/10 or 8/10 + 0 (oligohydramnios)

0-4/10 = HIGH RISK OF FETAL ASPHYXIA WITHIN ONE WEEK

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7
Q

BPP scoring - management of score 0-4/10

A

Delivery usually indicated

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8
Q

Modified BPP elements

A

NST + AFI
if abnormal, proceed to full BPP
Same SB rate as for BPP within 1/52 (0.8/1000)

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9
Q

BPP - scoring of NST

A

2 points if reactive:
- 2 or more episodes of FHR accelerations

Can be omitted if 8/8 otherwise; but always do if 6 or less

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10
Q

BPP - scoring of breathing movements

A

1 or more episodes of rhythmic breathing of 30s or more, within a 30 minute period

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11
Q

BPP - scoring of tone

A

1 or more episodes
of extension of a fetal extremity or fetal spine with return to flexion

(or opening closing of hand)

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12
Q

BPP - scoring of Amniotic fluid volume

A

single DVP 2cm or more
(x2cm horizontal)

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13
Q

BPP - scoring of fetal movements

A

3 or more discrete body or limb movements within 30 minutes

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14
Q

BPP - 4/10, risk of perinatal mortality within 1 week

A

91/1000
delivery for fetal indications

High probability of fetal asphyxia

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15
Q

BPP - 2/10, risk of perinatal mortality within 1 week

A

125/1000 - delivery for fetal indications
Fetal asphyxia almost certain

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16
Q

BPP - 0/10, risk of perinatal mortality within 1 weeks

A

600/1000, delivery for fetal indications
Fetal asphyxia certain.

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17
Q

NST - normal baseline

A

110-160

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18
Q

NST - atypical baseline

A

100-110;
>160 x <30min
rising baseline

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19
Q

NST - abnormal baseline

A
  • Bradycardia <100
  • Tachycardia >160 x >30min
  • Erratic baseline
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20
Q

NST - normal variability

A

6-25, or <5 x <40min

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21
Q

NST - atypical variability

A

<5 x 40-80 mins

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22
Q

NST - abnormal variability

A

<5 x >80 mins;
>25 x >10min
Sinusoidal

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23
Q

NST - normal decelerations

A

none or occasional variable

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24
Q

NST - atypical decelerations

A

variables x 30-60min

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25
Q

NST - abnormal decelerations

A

variables x >60min, or Lates

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26
Q

NST - normal accelerations

A

TERM: 2 or more x 15s x 15bpm in 40 min

PRETERM: 2 or more x 10s x10bpm in 40 min

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27
Q

NST - atypical accelerations

A

<2 x 40-80 min

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28
Q

NST - abnormal accelerations

A

<2 x >80 mins

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29
Q

Abnormal NST action

A

urgent action needed: US, or BPP , or delivery

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30
Q

chorionicity should be determined at?

A

11 - 13+6

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31
Q

twin growth discordance

A

20mm difference
or
20% EFW

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32
Q

twin dating USS - what discordance requires referral to tertiary center

A

CRL >10%
or
NT >20%

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33
Q

detection rate for major fetal aneuploidies in first trimester

A

40% low risk
66% high risk populations

34
Q

signs of chorionicity

A
  • number of placentas
  • fetal sex discordance
  • lambda sign
  • T sign
  • thickness of intertwin membrane
35
Q

risk of error in fetal sex determination

A

0-3%

36
Q

signs of fetal maturity on USS

A
  • distal femoral epiphysis (>32/40)
  • proximal tibial epiphysis (>37/40)
  • proximal humeral epiphysis (>38/40)
37
Q

most accurate time to date a pregnancy (singleton)

A

7-12/40

twins at 11-13+6

38
Q

changes in amniotic fluid volume can occur due to

A
  • hydration
  • maternal position
  • activity

likely facilitated by aquaporins

39
Q

chamberlain classification of oligohydramnios

A

SDP <2cm x 1cm

40
Q

chamberlain classification of polyhydramnios

A

SDP >8cm x 1cm

41
Q

what should be used for the initial assessment of amniotic fluid during routine obstetrical scanning

A

SINGLE POCKET
(chamberlain classification)

AFI may be used to help stratify polyhydramnios

42
Q

Intrapartum CTG: repetitive decels

A

3 or more in a row

43
Q

Intrapartum CTG: recurrent decels

A

decels that occur with >=50% of contractions in a 20 min period

44
Q

Intrapartum CTG: episodic gradual decel

A

gradual deceleration >=30s not associated with a contraction

45
Q

Intrapartum CTG: if EFM was initiated for abnormal IA, can discontinue after…

A

20 minutes minimum, of normal trace

if overall clinical picture consistent with low risk

46
Q

Intrapartum CTG: additional conditions when EFM may be beneficial

A
  • single UA
  • velamentous cord insertion
  • 3+ nuchal cord loops
  • use of CSE
  • labour dystocia
  • FHR arrhythmia
  • pre-pregnancy BMI >35
47
Q

Intrapartum CTG: significant/complicated variable decels

A

large amplitude and long duration

  • last >=60s
  • drop to =<60bpm or >=60 below baseline
48
Q

Intrapartum CTG: interruptions in EFM allowed

A

for 30 minutes to facilitate periods or ambulation, hydrotherapy, or position change, if:
- stable condition
- oxytocin infusion rate stable

49
Q

Intrapartum CTG: in active second stage, how often to check FH?

A
  • IA - every 5 min
  • EFM - every 15 min
50
Q

Intrapartum CTG: how often to assess and document MHR?

A
  • first stage, intact membranes: 4h
  • first stage, ruptures membranes: 2h
  • second stage: q15-30min
51
Q

Intrapartum CTG: paper speed

A

3cm/hr

52
Q

Intrapartum CTG: IA recommended for …?

A

low risk healthy women,
37 to 41+3

53
Q

Intrapartum CTG: IA can be used for 41+4 to 42+0, under what conditions?

A

documention of normal NST and LV

54
Q

Intrapartum CTG: how long to count for IA?

A

30-60s

55
Q

Intrapartum CTG: if no response to scalp stim, option?

A
  • FBS if available
  • ongoing vigilant evaluation
  • prompt delivery
56
Q

Intrapartum CTG: FBS suitable for which GA?

A

> 34/40

57
Q

Intrapartum CTG: FBS should be done if

A
  • Delivery not imminent
  • atypical or abnormal FHR not responding to conservative measures
  • no response to scalp stimulation
58
Q

Intrapartum CTG: protocol for assessment

A
  1. obtain interpretable data
  2. classify
  3. interpret within clinical picture
  4. communicate
  5. respond
  6. document
59
Q

Intrapartum CTG: continuous EFM is associated with?

A
  • higher rate of C/S and AVB
  • no significant difference in perinatal/neonatal M&M
  • 50% dec neonatal seizures but no clear difference in long-term sequelae
60
Q

Intrapartum CTG: IA, how often to check FH in first stage

A

q15-30min

61
Q

Intrapartum CTG: IA can continue with epidural use under what conditions

A
  • no other RFs
  • BMI <35
  • IA frequency increased to q5m x30min after top-ups
  • PCEA
62
Q

Intrapartum CTG: monitoring required pre/post foley balloon

A

30 mins each

63
Q

Intrapartum CTG: variability classifications

A

minimal =<5
moderate 6-25
marked >25

64
Q

Intrapartum CTG: atypical baseline

A
  • 100-110
  • > 160 x 30-80min
  • rising baseline
  • arrhythmia/irregular
65
Q

Intrapartum CTG: abnormal baseline

A
  • <100
  • > 160 for >80
  • erratic baseline
66
Q

Intrapartum CTG: atypical variability

A

=<5 bpm for 40-80min

67
Q

Intrapartum CTG: abnormal variability

A
  • <5bpm x >80min
  • > =25bpm x >10min
  • sinusoidal
68
Q

Intrapartum CTG: atypical accelerations

A

absence of acceleration with scalp stim

69
Q

Intrapartum CTG: abnormal accelerations

A

usually absent

70
Q

Intrapartum CTG: atypical decels

A
  • repetitive uncomplicated
  • non-repetitive complicated
  • intermittent lates
  • single prolonged decel but <3min
71
Q

Intrapartum CTG: abnormal decelerations

A
  • repetitive complicated
  • recurrent late
  • single prolonged decel 3-10min
72
Q

Intrapartum CTG: pseudosinusoidal pattern may be associated with

A
  • fetal thumb sucking
  • hiccoughing
  • rhythmic breathing
  • maternal opioids

r/o acidosis by scalp stim +/- FBS

73
Q

Intrapartum CTG: sinusoidal pattern

A

amplitude 5-15bpm for >=20 min

74
Q

Intrapartum CTG: prolonged accel

A

lasting >=2min

75
Q

Intrapartum CTG: baseline rise if…

A

sustained FHR raise for >=10min

76
Q

Intrapartum CTG: features associated with decelerations which increase likelihood of fetal hypoxia

A
  • rising BR
  • fetal tachycardia
  • absent or minimal baseline variability
  • delayed return to baseline
  • decel with a large area
77
Q

Intrapartum CTG: cx dilation required for FBS, and GA

A

2-3cm
>34/40

membranes should be ruptures

78
Q

Intrapartum CTG: normal pH and lactate values

A

> =7.25
<4.2

repeat FBS in 30m if CTG abnormality persists

79
Q

Intrapartum CTG: borderline pH and lactate

A

7.21-7.24
4.2-4.8

repeat within 30 min or consider delivery

80
Q

Intrapartum CTG: abnormal pH and lactate

A

=<7.20
>4.8

delivery is indicated

81
Q

Intrapartum CTG: features of complicated variables

A
  • failure to return to baseline
  • lasting long
  • deep
  • overshoot of 20bpm x20s
  • in presence of minimal or absent baseline variability
  • in presence of baseline tachycardia or bradycardia