7: Problems in pregnancy - large for dates Flashcards
What centiles are babies likely to be above/below if they are
a) large for dates
b) small for dates?
a) > 90th centile
b) < 10th centile
What is the definition of a large-for-dates baby?
Fundal height > 2cm greater than expected for gestational age
What is an innocent reason for a large-for-dates baby?
Mother has given the wrong dates
i.e can’t remember when her last pregnancy was, or has concealed it
Is macrosomia always caused by diabetes?
No, can occur on its own to produce a large-for-dates baby
What are three reasons for a large-for-dates pregnancy?
Multiple pregnancy
Foetal macrosomia
Gestational diabetes (causing macrosomia)
Polyhydramnios
Wrong dates given
How is foetal weight estimated?
Using ultrasound measurements - abdominal circumference and femur length
Macrosomia describes a foetus above which weight centile?
> 90th centile
What disease must you exclude in foetal macrosomia?
Maternal diabetes
What does dystocia mean?
Obstructed birth
e.g large-for-dates babies who can’t squeeze through the birth canal
What complication of pregnancy, causing brachial plexus injury or clavicle fracture, may occur in macrosomic babies?
Shoulder dystocia
What are the three options in managing foetal macrosomia?
Conservative - wait for due date and see what happens
Induction of labour
Caesarean section
What is polyhydramnios?
Excess amniotic fluid
How is excess amniotic fluid detected?
Abdominal examination - increased fundal height, increased liqour
Ultrasound measurements
What amniotic fluid index on ultrasound is diagnostic of polyhydramnios?
> 25cm
What is the depth of amniotic fluid diagnostic of polyhydramnios on ultrasound?
> 8cm
What is the
a) amniotic fluid index
b) pool depth
diagnostic of polyhydramnios?
a) API > 25cm
b) Deepest pool > 8cm
What endocrine disease can cause polyhydramnios?
Maternal diabetes
This seems like a safe answer for any problem in pregnancy tbh
Which type of pregnancy may cause polyhydramnios?
Multiple pregnancy
Polyhydramnios can cause __-__ labour.
pre-term labour
i.e premature birth
What is the main symptom of polyhydramnios?
Abdominal pain
What are the physical signs of polyhydramnios?
Tense, shiny abdomen
Inability to feel foetal parts
Excess liquor
What test should be done for all patients with suspected diabetes?
2 hour OGTT following overnight fast
This is the standard Ix in pregnant women with suspected gestational diabetes
If a patient with polyhydramnios hasn’t given birth by 40 weeks, how should it be managed?
Induction of labour
What is the definition of multiple pregnancy?
Presence of > 1 foetus in the womb
What infertility therapy increases a woman’s chances of multiple pregnancy?
Assisted conception therapy
Why does ACT increase a woman’s chances of multiple pregnancy?
Multiple embryos/zygotes can be artificially to increase chances of success
But if > 1 of those are successful then multiple pregnancy occurs
People from which part of the world are more likely to have multiple pregnancies?
Sub-Saharan Africa
What is the cause of monozygotic twins?
Splitting of one fertilised egg
What is the cause of dizygotic twins?
Two separate ova fertilised by two separate spermatozoa
Apart from zygosity, what other factor are twins described in terms of?
Chorionicity
i.e if there are one or two placentas
Dizygous twins always have ___ placenta(s) and ___ amniotic cavity / cavities.
dizygous twins –> two placentas, two amniotic cavities
i.e DCDA (dichorionic diamniotic)
What four forms can monozygous twins develop in?
DCDA - two placentas, two amniotic cavities
MCDA - shared placenta, two amniotic cavities
MCMA - shared placenta, shared amniotic cavity
Conjoined
What factor decides the form that monozygotic twins will develop in?
Point after fertilisation at which split occurs
Which imaging technique can be used to determine the chorionicity of twins?
Ultrasound
Which sign, found on ultrasound, can be used to differentiate DCDA and MCDA twins?
Lambda sign
Shows there are two placentas with a membrane between them
Why is it important to know the zygosity and chorionicity of a twin pregnancy?
Different forms of twin pregnancy have different complication risks
What is a possible symptom of multiple pregnancy?
Exaggerated morning sickness
Which hormone maintains the corpus luteum during pregnancy?
hCG
What happens to hCG levels during multiple pregnancy?
hCG levels are higher than normal
Why is multiple pregnancy dangerous?
Increased risk of maternal and foetal complications
Which dietary supplement is optional in most pregnant women but required in multiple pregnancy?
Iron
due to risk of anaemia
Which anti-platelet is given to women with multiple pregnancy?
Why?
Aspirin
To reduce risk of pre-eclampsia
Which dietary supplement is given to pregnant women to reduce the risk of their babies having neural tube defects?
Folic acid
Which scan are women with multiple pregnancy regularly given?
Ultrasound scan
What complication of monochorionic pregnancy results in one twin having polyhydramnios and the other having oligohydramnios?
Twin-twin transfusion syndrome
Multiple pregnancies are often delivered by which method?
Caesarean section
In what forms can a pregnant women have diabetes?
Either pre-existing Type 1, Type 2 diabetes or MODY
Or pregnancy-onset gestational diabetes
What are the complications of poorly-controlled diabetes, no matter its form, in pregnant women?
Pre-eclampsia
Polyhydramnios
Macrosomia and shoulder dystocia
Neonatal hypoglycaemia
Miscarriage
What are the common complications of diabetes which need to be monitored for in pregnant women?
Macrovascular disease
Microvascular disease - retinopathy, neuropathy, nephropathy
What is the HbA1c target in pregnant women?
< 48 mmol/mol
If a woman’s HbA1c is > ___ mmol/mol, they should avoid getting pregnant.
> 86 mmol/mol (or 10 units)
Which folic acid dose are women given if they have pre-existing diabetes and want to get pregnant?
5mg
As opposed to 400 micrograms for everyone else
The greater a pregnant woman’s ___, the greater her chances of developing diabetic complications.
greater HbA1c = greater complication risk
Which drug are pregnant women given if they are at increased risk of vascular complications?
Aspirin
What diseases does gestational diabetes increase a woman’s chances of developing post-partum?
Type 2 diabetes
Obesity
Cardiovascular disease
Which test is used to diagnose gestational diabetes?
2h OGTT
How is gestational diabetes managed?
Manage lifestyle (diet, exercise) as much as you can
Regular BG monitoring
Metformin OR Insulin injections / pump
Which form of delivery avoids shoulder dystocia in macrosomic babies?
Caesarean section
When is the target delivery gestation for women with pre-existing diabetes?
38 weeks
How often do women with pre-existing diabetes receive foetal ultrasound scans during pregnancy?
Every 4 weeks from 28 weeks
