Fetal growth Flashcards
What is SFD
Small for date
Measurement below 10th population centile for gestational age
What is LFD
Large for date
Measurement above 95th population centile for gestational age
What is gestational age centile chart affected by
Maternal BMI and ethnicity
How can fetal growth be measured
Symphysis fundal height (30-40% sensitive) USS (90-95% sensitive): Abdominal circumference Femur length Head circumference
Definition of fetal growth restriction
Fetus failed to reach genetic growth potential
<5th centile for gestational age (5-10th can be normal variation e.g small mother)
Risk factors for fetal growth restriction (12)
Smoking Alcohol Substance use 1st trimester bleeding Domestic violence Previous FGR Recurrent fetal loss Raised AFP Placenta insufficiency Hypertension Infection Renal disease
Reasons for SFD
Normal variation (healthy baby) Placental insufficiency Infection (CMV common) Chromosomal abnormality Incorrect date/measurement - dating scans 4 weeks apart to confirm gestational age and correct measurements
How to assess placental function
Uterine artery Doppler
Resistance to flow shows diastolic notching or reverse diastolic flow (more severe)
Normal small vs FGR
Healthy baby symmetrical
Liquor volume normal in healthy, can be increased in chromosomal effect/infection, can be reduced in placental insufficiency
Uterine artery Doppler shows resistance to flow in placental insufficiency
Which Doppler scans can be used for surveillance of FGR
Umbilical artery - shows increases in placental resistance to flow
Middle cerebral artery - increased flow shows placental resistance to flow
Ductus venosus - predicts need for delivery
Monitoring for GFR
Maternal monitoring: regular BP and urine dipstick checks
Fetal monitoring: fetal movements, Doppler, amniotic volume measurements, biophysical profile
When should you deliver a FGR with abnormal UMA Doppler
<37 weeks
When should you deliver a FGR with AREDF
> 34 weeks
Under what circumstances should you deliver a FGR with AREDF before 34 weeks
Abnormal CTG
Abnormal Doppler
Abnormal biophysical profile
When should the Doppler scans be done
Assess risks for IUGR at booking visit and then if necessary organise:
Uterine artery - 20-22 weeks
Umbilical artery - 1st line if FGR suspected at 26-28 weeks
MCA and DV - if UMA abnormal
Causes of increased symphysis fundal height
Macrosomic baby Fibroids Pelvic mass Polyhydramnios Maternal obesity
Causes of a macrosomic baby
Gestational diabetes Maternal obesity Increased maternal age Multiparity Constitutionally large baby Male fetus Postmaturity baby
Risks of macrosomic baby
Prolonged labour/ postpartum haemorrhage Genital tract trauma Perinatal asphyxia Shoulder dystocia Neonate hypoglycaemia Metabolic syndrome
How to test for gestational diabetes
Oral glucose tolerance test
HbA1c >30 weeks
When should Caesarian section be offered for diabetes and macrosomia
Diet controlled <40 weeks
Metformin controlled at 39 weeks
Insulin controlled at 38 weeks
Due to increased stillbirth risk
Any macrosomia at 38 weeks
What week gestation is uterus fundus felt at pubic symphysis
12
What week gestation is uterus fundus felt at umbilicus
22
What week gestation is uterus fundus felt half way between umbilicus and xiphisternum
28
What week gestation is uterus fundus felt at xiphisternum
36
What is the 1st trimester
1-12
What is the 2nd trimester
13-28
What is the third trimester
29-40
