Foetal growth Flashcards
how is fetal growth measured?
abdominal palpation of fundal height
symphysio-fundal height
USS: head circumference, abdominal circumference, femur length
What is low birth weight
<2500g
causes of small for gestational age
constitutionally small
fetal growth restriction (IUGR)
fetal growth restriction
placenta-mediated growth restriction
non-placenta mediated growth restriction
placenta-mediated growth restriction causes
idiopathic pre-eclampsia maternal smoking maternal alcohol anaemia malnutrition infection maternal health conditions
non-placenta mediated growth restriction causes
genetic abnormalities
structural abnormalities
fetal infection
errors of metabolism
signs of fetal growth restriction
reduced amniotic fluid volume
abnormal Doppler studies
reduced fetal movements
abnormal CTGs
short-term complications of FGR
fetal death or stillbirth
birth asphyxia
neonatal hypothermia
neonatal hypoglycaemia
why does FGR cause increase morbidity and mortality?
Intrauterine hypoxia
Acidaemia
Prematurity, iatrogenic
Neonatal complications
increased risk of which conditions in growth restricted babies?
Cardiovascular disease, particularly hypertension
Type 2 diabetes
Obesity
Mood and behavioural problems
risk factors for small gestational age
Previous SGA baby
Recurrent fetal loss
Previous unexplained small baby
Raised AFP
Infection
Placental pathology (praevia, cirumvallata)
Obesity
Smoking, alcohol, substance abuse
Domestic violence
Prescription and OTC drugs
High altitude
Diabetes
Existing hypertension
Pre-eclampsia
Older mother (over 35 years)
Multiple pregnancy Low pregnancy‑associated plasma protein‑A (PAPPA) Haemoglobinopathies Collagen vascular disease Renal disease Antepartum haemorrhage Antiphospholipid syndrome
high risk factors for small gestational age
Previous FGR is biggest risk factor
Recurrent fetal loss
Previous unexplained stillbirth
1st trimester bleeding
Smoking
Unexplained raised AFP
reasons for small fetus
Normal small:
Constitutionally small, healthy baby
Abnormal small:
Chromosomal abnormalities
Syndromes
Congenital malformations
Infected small:
Infection during pregnancy
Commonly CMV
Starved small: Placental FGR most common cause Poor placentation Smoking Maternal disease affecting placenta Multiple pregnancy
Wrong small:
Incorrect dates or measurements
How to differentiate small for dates from fetal growth restriction
centile position symmetry liquor volume UMA doppler growth velocity
Symphysio-fundal height <10th centile:
next step
serial growth scans with umbilical artery doppler
when are women booked for serial growth scans with umbilical arteyr doppler?
SFH <10th centile
three or more minor risk factors
one or more major risk factos
issues with measuring SFH (large fibroids, BMI>35)
What is measured on serial USS in women at risk or with SGA
Estimated fetal weight (EFW) and abdominal circumference (AC) to determine the growth velocity
Umbilical arterial pulsatility index (UA-PI) to measure flow through the umbilical artery:
End-diastolic flow velocity (continuous, absent, reversed) reflects increases in placental resistance
Essential in surveillance of the growth restricted fetus
Amniotic fluid volume
management of small baby
Identifying those at risk of SGA
Confirm dates
Assess growth by ultrasound
Review measurements
Aspirin is given to those at risk of pre-eclampsia
Treating modifiable risk factors (e.g. stop smoking)
Serial growth scans to monitor growth
Early delivery where growth is static, or there are other concerns
investigations for SGA
blood pressure urine dipstick uterine artery doppler scanning detailed fetal anatomy by fetal medicine karyotyping for chromosomal abnormalities testing for infections
macrosomia weight at birth
> 4.5kg
causes of increased symphysio-fundal height in singleton pregnancy
uterine fibroids
pelvic mass pushing up the uterus
polyhydramnios
obesity
causes of macrosomia
Constitutional
Maternal diabetes
Previous macrosomia
Maternal obesity or rapid weight gain
Overdue
Male baby
maternal factors causing macrosomia
Diabetes
Obesity
Increased maternal age
Multiparity
Large stature
fetal factors causing macrosomia
constitutional
male gender
post-maturity
genetic disorder
macrosomia risks to mother
Shoulder dystocia Failure to progress Perineal tears Operative delivery: Instrumental delivery or caesarean Postpartum haemorrhage Uterine rupture (rare) Prolonged labour Genital tract trauma
macrosomia risks to fetus
Birth injury (Erbs palsy, clavicular fracture, fetal distress and hypoxia)
Perinatal asphyxia from difficult delivery
Shoulder dystocia/ Erb’s palsy
Metabolic syndrome
Neonatal hypoglycaemia
Obesity in childhood and later life
Type 2 diabetes in adulthood
investigations for large baby
USS: polyhydramnios
OGTT: gestational diabetes
prematurity weeks
Under 28 weeks: extreme preterm
28 – 32 weeks: very preterm
32 – 37 weeks: moderate to late preterm
prematurity associations
Social deprivation Smoking Alcohol Drugs Overweight or underweight mother Maternal co-morbidities Twins Personal or family history of prematurity
risk factors for prematurity
Spontaneous pre-term birth
Mid-trimester loss (16+)
PPROM
Cervical trauma
