small/large for dates Flashcards
definition of preterm baby
delivery before 37 weeks
extreme = 24 - 27+6
very = 28 - 31+6
moderate to late = 32 - 36+6
aetiology of preterm birth
infection
over-distension (multiple/polyhydramnios)
vascular (placental abruption)
intercurrent illness (pyelonephritis, appendicitis, pneumonia)
cervical incompetence
idiopathic
risk factors for preterm birth
previous PTL multiple uterine abnormalities age (teenagers) parity (=0 or >5) ethnicity poor socio-economic status smoking drugs (esp cocaine) low BMI (<20)
definition of small for gestational age
estimated fetal weight or abdominal circumference below the 10th centile
what is IGUR
intra uterine growth retardation
failure to achieve growth potential
definition of low birth weight
brith weight below 2.5 kg (regardless of gestation)
symmetrical vs asymmetrical IUGR
symmetrical = small head and small body asymmetrical = normal head and small body
screening for SGA
symphysis fundal height
growth scan if single measurement below 10th centile on customised chart
serial measurements suggest slow/static growth
diagnosis of SGA
measurement of fetal AC
combine with head circumference +/- femur length to give EFW
additional information may come from liquor volume or amniotic fluid index and dopplers
maternal factors for SGA
lifestyle (smoking, alcohol, drugs)
height and weight
age
maternal disease eg HTN
placental factors for SGA
infarcts
abruption
often secondary to HTN
fetal factors for SGA
infections (rubella, CMV, toxoplasma) congenital anomalies (absent kidneys) chromosomal abnormalities (down's)
antenatal/labour consequences of IUGR
risk of hypoxia and/or death
post natal consequences of IUGR
hypoglycaemia effects of asphyxia hypothermia polycythaemia hyperbilirubinaemia abnormal neurodevelopment
clinical features of poor growth
predisposing factors
feudal height less than expected
reduced liquor
reduced fetal movements
what does an umbilical arterial doppler measure
placental resistance to flow
indications for delivery earlier than 37 weeks
growth becomes static (IOL may be appropriate)
abnormal umbilical artery doppler
normal umbilical artery doppler with abnormal MCA between 32 and 37 weeks
abnormal umbilical artery doppler with abnormal ductus venous doppler between 24 and 32 weeks
definition of large for gestational age
symphysis fundal height >2 cm for gestational age
what is fetal macrosomia
‘big baby’
USS EFW >90th centile
risks of fetal macrosomia
clinician and maternal anxiety
labour dystocia
shoulder dystocia
PPH
management of fetal macrosomia
exclude diabetes
reassure
conservative vs IOL vs c-section delivery
what is polyhdramnios
excess amniotic fluid
amniotic fluid index >25 cm
causes of polyhydramnios
maternal diabetes fetal anomaly (GI atresia, cardiac, tumour) monochorionic twin pregnancy hydros fetalis fetal viral infection idiopathic
clinical features of polyhydramnios
abdominal discomfort prelabour rupture of membranes preterm labour cord prolapse LFD malpresentation tense shiny abdomen inability to feel fetal parts
diagnosis of polyhydramnios
USS
amniotic fluid index >25 cm
deepest vertical pocket >8 cm
investigations for polyhydramnios
oral glucose tolerance test
serology (toxoplasmosis, CMV, parvovirus)
antibody screen
USS
management of polyhydramnios
serial USS (growth, LV, presentation) IOL by 40 weeks
risks of polyhydramnios during labour
malpresentation
cord prolapse
preterm labour
PPH
risk factors for multiple pregnancy
assisted conception African race FHx increased maternal age increased parity tall women > short women
what is zygoisity (relating to multiple pregnancy)
monozygotic = splitting of a single fertilised egg dizygotic = fertilisation of 2 ova by 2 sperm
what is chorionicity
1 placenta/2 placentas?
what is the chorionicity of dizygous twins
always DCDA
dichorionic diamniotic
what is the chorionicity of monozygous twins
MCMA/MCDA/DCDA
depends on time of splitting of ovum
cleavage occurs when to DCDA monozygous twins
day 0 - 3
cleavage occurs when for MCDA twins
day 4 - 7
cleavage occurs when for MCMA twins
day 8 - 14
cleavage occurs with for conjoined twins
day 15 onwards
why is chorionicity important
monochorionic twins are at higher risk of pregnancy complications
USS sign for DCDA twins
lambda sign
USS sign for MCDA twins
T-sign
clinical features of multiple pregnancy
exaggerated pregnancy symptoms
high AFP
large for dates uterus
multiple fetal poles
confirmation of multiple pregnancy
USS at 12 weeks
complications of multiple pregnancy
higher perinatal mortality congenital anomalies IUD pre term labour growth restriction cerebral palsy twin to twin transfusion
maternal complications of multiple pregnancy
hyperemesis gravidarum anaemia pre-eclampsia antepartum haemorrhage (abruption, placenta praaevia) preterm labour c-section
how regular should clinic appointments be for multiple pregnancy
every 2 weeks for MC
every 4 weeks for DC
timing of delivery in multiple pregnancy
DCDA 37-38 weeks
MCDA 36+0 with steroids
what is gestational diabetes
carbohydrate intolerance resulting in hyperglycaemia of variable severity with onset or first recognition during pregnancy
complications specific to pre-existing maternal diabetes
congenital anomalies
miscarriage
IUD
complications common to pre-existing and gestational diabetes
pre-eclampsia polyhydromanios macrosomia shoulder dystocia neonatal hypoglycaemia
risk factors for gestational diabetes
previous GDM BMI >30 FHx ethnicity previous big baby polyhydramnios big baby glycosuria
glycemic targets
fasting 3.5 - 5.5 mmol/l
1 hr <7.8 mol/l
timing of delivery in GDM
insulin treatment 38 weeks
metformin treatment 39-40 weeks
diet alone 40-41 weeks
folic acid supplements in GDM
5 mg
