General Obs 2 Flashcards
Is it big or small ?
Is it growing normally or not?
These are two different questions. What measurements do you need?
for big / small - only one measurement
for growing normally - series of measurements
Define ‘small for dates’
Weight is less than 10th centile for its gestation
Define ‘IUGR’
failed to reach full growth POTENTIAL
e.g. meant to be 4kg at term but 3kg
Which chart uses ‘criterion referencing’ (based on mum’s height, booking weight, BMI, ethnicity & parity)?
Customised foetal growth chart
Top line is 90th centile, middle 50th, bottom 10th centile
left axis of customised foetal growth chart?
symphyso-fundal height (cm)
right axis of customised foetal growth chart?
estimated foetal weight (g)
Bottom axis of customised foetal growth chart?
gestation (wks)
at 24 wks, what would symphyso-fundal height be?
21-27cm (3 either side)
at 30 weeks, what would symphyso-fundal height be?
27-33cm
How is ‘estimated foetal weight (g)’ calculated?
BIOMETRY from ultrasound
or by formulas (varies hosp to hosp)
For foetal biometry, what are the main measurements from the ultrasound?
HC - head circumference
AC - abdo circumference
FL - femur length
these come together to make estimated foetal weight
What’s the commonest cause of IUGR ?
PLACENTAL INSUFFICIENCY
*foetal factors like chromosomal abnormality can also cause IUGR
Placental insufficiency is the most common cause of IUGR. Give me some risk factors for placental insufficiency.
- pre-eclampsia!
- smoking!!
- twins
- maternal malnutrition
Instead of actual IUGR (pathological) , they might just be constitutionally small for dates. Name 3 risk factors for Small for Dates.
- low parental height
- female foetus
- ethnicity (inc Asian)
A symmetrically small fetus is more likely to be constitutionally small for dates,
… whilst an ASYMMETRICALLY small fetus is more likely to be caused by IUGR (placental insufficiency).
True or false?
True :)
in terms of circumferences
Which circumference is the first bit to slow down if placental insufficiency?
abdominal circumference
What does AFI stand for?
amniotic fluid index
How is the amniotic fluid index measured?
ultrasound
amount of fluid in each of the four quadrants.
What is a normal AFI?
8-18cm
AFI counts as oligohydramnios?
<5th centile for gestational age
usually <5cm
AFI counts as polyhydramnios?
> 95th centile for gestational age
usually >24cm
Which investigation is used for the diagnosis of IUGR?
ultrasound, plotting biometry on customised foetal growth chart
When IUGR is confirmed from the customised foetal growth chart, what investigations is the woman offered ongoing?
ultrasound every fortnight
umbilical artery Doppler every fortnight
Give me 4 SHORT TERM complications associated with IUGR?
perinatal asphyxia
hypo/hyperglycaemia
polycythaemia
persistent pulm HTN of newborn
Give me 3 LONG TERM complications associated with IUGR?
learning difficulties
behavioural problems
more prone to obesity, HTN, metabolic syndrome (heart disease, stroke, T2DM)
Babies with IUGR are more likely to develop chronic diseases earlier. True or false?
trrruuuuee
What does placental insufficiency often do to amniotic fluid levels?
oligohydramnios
(less amniotic fluid made by baby’s kidneys bc of low renal perfusion- it’s diverting blood to brain bc of chronic hypoxia)
What makes amniotic fluid?
baby’s wee
swallows it and wees it out again
Name 3 causes of oligohyrdramnios
PROM (leaks) placental insufficiency (less renal perfusion)
foetal urinary tract malformations (renal agenesis)
also…
chromosomal abnormalities
post term gestation (we dont know why)
Ultrasound shows oligohydramnios. If placental insufficiency is suspected, What extra test would you do?
umbilical artery Doppler
Why can oligohydramnios lead to muscle contractures at birth?
they cant exercise by swimming around in the amniotic fluid
The management of oligohydramnios depends on the underlying cause. What are the two commonest causes of oligohydramnios?
PROM
placental insufficiency
The earlier the oligohydramnios occurs, the _______ the prognosis.
The earlier the oligohydramnios occurs, the worse the prognosis.
In placental insufficiency, what would be the likely result of umbilical artery Doppler?
absent end diastolic flow.
a.k.a foetal vascular stress
What is a NORMAL finding on Umbilical artery Doppler?
POSITIVE end-diastolic flow
Midwife suspects large for dates. How would she have come to this?
serial symphyso-fundal heights crossed the 90th centile
What investigations in large for dates?
oral GTT
ultrasound
(+BP obvs)
Ultrasound shows that head circumference and femur length are on the 50th centile, whereas abdominal circumference is on the 95th centile. This is …..
asymmetrical macrosomia
What is the difference between large for dates and macrosomia?
large for dates = birth weight greater than 90th percentile for gestational age
macrosomia = birth weight >4kg
When can large for dates and macrosomia be diagnosed?
After birth
cant estimate weight properly in utero
In macrosomia, baby is more at risk of birth complications such as …
shoulder dystocia
birth injuries e.g. fractures, palsies
What is the absolute main cause of macrosomia
gestational DIABETES
can also be heavy parents but bit extreme like
Over half of polyhdramnios is idiopathic. Yeah?
yeah
Over half of polyhdramnios is idiopathic. But name 6 other causes of polydramnios. You can.
genetic/chromosomal abnormalities - trisomy 13,18,21
oes / duodenal atresia (stop foetus swallowing)
macrosomia! maternal diabetes
multiple preg! twin to twin transfusion syndrome
foetal anaemia
hydrops
No medical intervention is required in the majority of women with polyhydramnios. True or false?
true
If polydramnios picked up late, what symptom can the mum have?
breathlessness
On routine antenatal examination it is difficult to palpate foetal parts, and chart shows large for dates. Differential diagnosis? (x3)
polyhdramnios (yep)
macrosomia
multiple preg!
What is hydrops fetalis?
Abnormal accumulation of fluid in two or more foetal compartments.
Including:
ascites, pericardial effusion, pleural effusion, subcutaneous OEDEMA
What is the key cause of hydrops fetalis?
ANAEMIA
e. g. Rhesus disease
e. g. Parvovirus B19, other infections
e. g. alpha thalassemia
Treatment for severe hydrops?
foetal blood transfusion
Treatment of polyhydramnios depends on underlying cause, mostly no intervention. What 2 interventions can be considered in severe polydramnios where maternal symptoms are severe?
INDOMETACIN - stop baby weeing
AMNIOREDUCTION - drain amniotic fluid - risky
when delivered, baby has to be check for oes. atresia by paediatrician passing NG tube
Polyhydramnios increases the risk of what three complications??
preterm labour
malpresentation
PPH
Which can the extra-fluid-compartments be in hydrops? (x4)
ascites,
pericardial effusion,
pleural effusion,
subcutaneous OEDEMA
When do you use indomethacin
polyhydramnios - stop baby weeing
close PDA
the two types of PROM?
PROM
preterm PROM
define PROM
rupture of membranes at least 1 hr prior to the onset of labour
4 risk factors for PROM
genital infection polyhydramnios cervical insufficiency smoking in preg amniocentesis
what test is done in all cases of PROM?
HIGH VAGINAL SWAB
what test can be used to check its actually the waters and not just vaginal discharge
Actim-PROM
two bits of the foetal membranes are
chorion , amnion
suggest two infections that commonly cause PROM
GBS
BV
2 complications of PROM?
oligohydramnios
chorioamnionitis
management of PROM <34wks?
expectant..
prophylactic erythromycin + corticosteroids
management of PROM >36wks?
induce + deliver if lasts >24hrs
IV penicillin during labour if GBS
management of PROM between 34 - 36wks?
induce!!
IV penicillin during labour if GBS
