Fetal growth & nutrition Flashcards
Outline the embryo& fetal growth patterns
- ) stage I (hyperplasia): Rapid mitosis and increase of DNA content; 4-20weeks
- ) Stage II(hyperplasia& hypertrophy): Declining mitosis with increase in cell size; 20-28 weeks
- ) Stage III (hypertrophy): rapid increase in cell size;, rapid accumulation of fat,muscle, CT; 28-40weeks
When is the greatest fetal weight increase
3rd trimester
What landmarks does the crown-rump length(CRL) measurement involve
- Top of head( crown)
- Bottom of buttocks (rump)
- CRL may be used to date pregnancy
Describe the ultrasound assessment of 1st trimester
- Routine scan approx 12 weeks from last menstrual period
- Viability
- CRL measurement
- used to date pregnancy
- If CRL>/= 84.1mm=date by head circumference
- Also offer screening for trisomies
Describe the ultrasound assessment of 2nd trimester
-Routine anomaly scan
-18-20weeks
-Assess fetal growth, fetal anomalies, placental site
4 standard growth measurements; fetal growth/biometry:
-Head circumference
-Bi-parietal diameter
-Abdominal circumference
-Femur length
Combine to estimate fetal weight
What is the symphysial fundal height (SFH)?
-Fundus (variable) to pubic symphysis( fixed)
If there are concerns about growth another scan can be taken in 2nd/3rd trimester. What does this involve?
- Biometry (HC, BPD, AC, FL)
- Amniotic fluid index
- Umbilical artery doppler
What are the risk factors for a small gestational age ( SGA) fetus
- Current/demographic risks: small petite woman
- Previous pregnancy risks: previous SGA fetus or FGR seen
- Maternal medical history: hypertension, diabetes, chronic kidney disease, pre-eclampsia
- Current pregnancy complications: e.g pre-eclampsia
Outline fetal growth in high risk pregnancy due to twins
- ) Dichorionic (two placentae)
- lower risk of problems
- scan every 4 weeks - ) Monochorionic ( shared placenta)
- higher risk of problems
- scan every 2 weeks
- selective IUGR
- Twin-to-twin-transfusion
Outline the principles of SGA pregnancy management
Screen and identify at risk pregnancies
-Aspirin if low PAPP-A/ risk of PET
-Uterine artery dopplers
Monitor with scans
-If abnormal growth-increase frequency of scans
-If FGR/functional concerns- consider early delivery (steroids)
-If SGA- consider induction at 37week
What does it mean when a baby is large for gestational age
Estimated fetal weight >90th centile
-Macrosomia
-Birth weight> 4kg
(approx 10% of babies)
What does it mean when a baby is small for gestational age
SGA 1.) infant: birth weight< 10th centile 2.) fetus: EFW or AC< 10th centile Severe SGA -fetus: EFW or AC< 3rd centile -higher chance of FGR
What are the risk factors for LGA?
- Constitutional ( large/tall parents)
- Raised BMI
- Previous LGA baby
- diabetes : type 1,2 & gestational
Outline the morbidity& mortality for a LGA fetus
- ) perinatal complications
- shoulder dystocia
- brachial plexus nerve injury
- fractured humerus/clavicle
- birth asphyxia/still birth - ) If diabetic pregnancy
- hypoglycaemia - ) Maternal complications; increased risk of:
- C-section/ instrumental
- perineal trauma/tears if vaginal birth
- postpartum haemorrhage
What does it mean if a fetus is growth restricted
Fetal growth restriction( FGR)/ in-utero growth restriction ( IUGR)
- Pathological restriction of genetic growth potential
- may have evidence of fetal compromise ( abnormal AFI- amniotic fluid index /dopplers)
