Foetal Problems In Pregnancy Flashcards
What is a CTG?
Cardiotocography
Foetal heart trace + maternal uterine activity plotted on same graph
Assess at X time points
Normal foetal HR = 100-160bpm
Any contractions should be mirrored by an increase in babies HR variability = normal
Short episodes (<40mins) of deceased variability are likely due to sleeping foetus, if greater, start to worry
Dropping baseline, bradycardias….. are bad signs
What are some pathological factors that would reduce HR variability on a CTG?
Maternal drugs:
Benzos, opioids
Foetal acidosis - usually due to hypoxia (from placental insufficiency)
Prematurity - <28wks
Foetal tachycardia - >140bpm
Congenital heart abnormalities
What are some descriptions of the foetal trace?
Baseline bradycardia:
HR <100bpm- possible maternal beta blocker use
Baseline tachycardia:
HR <160bpm - maternal pyrexia, hypoxia, chorioamnionitis
Loss of baseline variability:
<5bpm - prematurity, hypoxia
Early deceleration:
HR deceleration at the start of a contraction + return to normal after - normally innocuous, baby head being squished
Late deceleration:
HR deceleration lags behind the onset of the contraction and doesn’t return to normal until 30s after it ends - indicated foetal distress e.g. placental insufficiency
Variable decelerations:
Independent of contractions - possible cord compression
What is the mnemonic for interpreting CTG’s?
DR C BRAVADO
Define Risk:
Hx = increased age, SGA, aburption, PROM etc)
Contractions:
4 in 10 = labour
Braxton Hicks will be fewer, may last a couple hours and settle
>5 in 10 or lasting >2mins at at time = hyperstimulation (more common in induced labour, leading to uterine rupture or foetal distress), needs calming with a tocolytic (terbutaline)
Baseline RAte:
Foetal HR = 110-160
Brady - hypoxia, e.g. cord compression - >3mins of brady = tired + hypoxic and needs senior review and probably C-section
Tachy - e.g. infection
Variability:
Signifies balance between parasympathetic and sympathetic activity in foetus
>5 = normal
Loss of variability in hypoxia
Accelerations:
Increase in HR of >15bpm above the baseline for >15s = just note if present and if they time with contractions or not
Decelerations:
Decrease in HR of >15bpm for > 15s
Early = occur with contractions - if present for >90mins, need review
Late = occur after contractions/unrelated to = hypoxia; if present for >30 mins, need management
Outcome:
What is the plan given the information above?
What is the definition of:
Intrauterine growth restriction?
Small for gestational age?
Low birth weight baby?
IUGR - failure to maintain a pattern of growth over serial scans - sequentially dropping centiles on a personalised growth chart
SGA - baby weight bellow the 10th centile at a single given gestation; if happens over a few scans = IUGR
LBW - baby born at less than <2.5kg
What are the types of IUGR?
Symmetrical vs asymmetrical
Symmetrical you think of factors intrinsic to the foetus e.g. genetics (trisomy 18 + 13) OR infection e.g. TORCH + parvo
Asymmetrical you think of placental problems e.g. maternal hypertension, maternal thrombophilic disorders, placental implantation over a fibroid, other maternal chronic disease (eating disorder, poor nutritional status, anaemia)
What counts as large for gestational age? High birth weight baby/macrosomia?
> 90th centile on personalised growth chart at a given point
Macrosomia - >4.5kg
What are some causes of LGA?
Maternal DM or GDM (though maternal T1DM may produce SGA babies - smaller/sclerosed placental arteries = less blood to baby) - high levels of sugar
= increased foetal insulins (maternal insulin does not cross placenta) = increased sugar uptake + gluconeogensis (-fat deposition) + increased insulin-like growth factor (-increased foetal growth rate)
Foetal fluid retention - heart failure (e.g. congenital heart disease; Rh incompatibility or parvovirus infection = haemolytic anaemia - foetal heart failure - fluid retention - increase baby size)
