Large for Dates Flashcards
What defines a large for date baby?
symphyseal-fundal height >2cm for gestational age
What can cause a large for date baby?
fetal macrosomia
polyhydraminos
diabetes
multiple pregnancy
How is fetal macrosomia diagnosed?
on ultrasound
- estimated fetal weight >90th centile
- estimated abdominal circumference >97th centile
What are the risks of fetal macrosomia?
clinician and maternal anxiety
labour dystocia - difficult birth
shoulder dystocia - more common in diabetics - anterior shoulder gets caught above the mothers pubic bone
post partum haemorrhage
How do you manage fetal macrosomia?
exclude diabetes
reassure
c/section if baby >4.5kg
What is polyhydraminos?
excess amniotic fluid
How is polyhydraminos defined?
amniotic fluid index >25mm
deepest pool >8cm
What causes polyhydraminos?
maternal diabetes - most common idiopathic - 2nd most common fetal anomaly - GI atresia, cardiac, tumours monochorionic twin pregnancy hydrops fetalis viral infection
How does polyhydraminos present?
abdo discomfort
pre labour rupture of the membranes
preterm labour
cord prolapse
What are the signs of polyhydraminos?
large for date
malpresentation
acute shiny abdomen
inability to feel foetal parts
How is polyhydraminos diagnosed?
USS for AFI and DP
What investigations should be done for polyhydraminos?
OGTT - to exclude diabetes
serology - toxoplasmosis, CMV, parvovirus
antibody screen
How is polyhydraminos managed?
induce labour by 40 weeks
serial ultrasounds
What’re the risks of polyhydraminos?
malpresentation
cord prolapse
preterm labour (before 37 weeks)
PPH
What are the spontaneous risks of twins and triplets?
twins = 1 in 80
triplets 1 in 10,000
What increases your chances of having multiple pregnancies?
assisted conception race - african more common family history increased maternal age increased parity tall women >short women
What is more common - dizygotic or monozygotic?
dizygotic - 70%
What are dizygotic twins?
fertilisation of two ova by two sperm
What are monozygotic twins?
splitting of a single fertilised egg
What are the two types of chorionicity?
dizygotic chorionic - 1 placenta (dichorionic diamniotic DCDA)
monozygotic chorionic - 2 placentas - can be MCMA, MCDA o
What do DCDA twins come from?
morula
day 0-3 after implantation
What do MCMA twins come from?
implanted blastocyst
day 8-14 after implantation
What do MCDA twins come from?
blastocyst
day 4-7 after implantation
How is chorionicity determined?
ultrasound
What do dizygotic chorionic look like on USS?
lambda sign
What do monozygotic chorionic look like on USS?
T sign
What type of twins are at highest risk of pregnancy complications?
MCMA and MCDA
What are the symptoms of multiple pregnancy?
exaggerated pregnancy symptoms - ie sickness
What are the signs of multiple pregnancy?
high AFP
large for dates uterus
multiple foetal poles
When are multiple pregnancies confirmed on USS?
12 weeks
What are the foetal complications that may occur due to multiple pregnancy?
congenital abnormalities eg acardiac twin
intrauterine death
growth restriction - both or disconcordant
cerebral palsy - twinsx8 higher, tripletsx4 higher
twin-twin transfusion - oligohrydroaminos+polyhydraminos
What are the maternal complications that may occur due to multiple pregnancies?
hyperemesis gravidarum anaemia pre eclampsia antepartum haemorrhage preterm labour cesarean section
How does the antenatal management of monochorionic twins differ?
clinic appointments every 2 weeks
ultrasounds 2 weekly from 16/40
How does the antenatal management of dichorionic twins differ?
clinic appointments every 4 weeks
ultrasounds every 4 weeks
What are monochorionic twin complications?
single fetal death selective growth restriction twin to twin transfusion syndrome (TTTS) twin anaemia - polycythermia sequence (TAPS) absend EDV or reversed EDV
What is twin to twin transfusion syndrome (TTTS)?
syndrome with artery-vein astamoses
donor twin perfuses the recipient twin
When should DCDA twins be delivered?
37-38 weeks
When should MCDA twins be delivered?
after 36+0 weeks with STEROIDS
How should MCMA, triplets etc be delivered?
c/section
What time should be aimed for between twins birth?
<30mins
syntocinon after twin 1
