SGA in Pregnancy Flashcards
When do you first start feeling fetal movements?
Primiparous: 18-20wks
Multiparous: 15-16wks
From what week gestation does fetal movement become a reliable indicator of fetal wellbeing?
Post 28weeks gestation
However we still reccommend women begin to track the fetal movement past 18 weeks to become familiar with the pattern
What is reduced/absent fetal movements associated with?
fetal death/stillbirth
What is the definition of SGA?
Babies that track below the 10th centile for birthweight for their gestational age, as defined by their sex/ethnicity adjusted GROW chart
What are the two main patterns of growth restriction?
- Asymmetric:
- When abdo growth is disproportionately low when compared with the head (head circumference)
- Symmetric “global growth restriction”
- all measurements are small (biparietal diameter, head circumference, abdo circum, femur length)
When does asymmetric growth of a fetus usually occur and what are the common causes?
Usually more significant at later gestational ages
Suggests poorer uteroplacental circulation and a reduced supply of nutrient to the fetus.
Usually extrinsic factors:
- Chronic HTN
- Severe malnutrition
- Genetic mutations
When does Symmetric growth of the fetus occur and what are the common causes
More often in early gestation and more likely to have permenant impacts on the fetal neurology.
- Early intrauterine infection (CMV, rubella, toxoplasmosis)
- Chromosome abnormalities
- Anaemia
- maternal substance abuse
- Early onset placental disease (PET)
Asymmetric fetal growth can increase the risk of?
Fetal hypoxia and fetal hypoglycaemia
When does being a twin start to impact on growth?
Only >30-32 weeks will being a twin slow and reduce the growth from the norm,
Pre-natal risk factors of SGA?
- Smoking
- Underweight
- >>>maternal age
- asian/indian
- Nulliparity
- Mother born SGA
- cocaine
- Chronic HTN
- CKD
- Anti-phospholipid
- Malaria
- Pre-gest DM
Antenatal risk factors for SGA
- Heavy bleeding in early pregnancy
- Placental abruption
- Pre-eclampsia
- Gest HTN
- Gest DM
Common Causes of SGA:
- Fetal genetic abnormalities (5-20%): aneuploidy, uniparental disomy etc
- Fetal infection (5-10%)
- CMV and toxo
- also rubella, varicella zoster, malaria, syphyllis and HSV
- Fetal structural abnormality
- Multiple gestation
- Ischaemic placental disease
- Placental abnormality
- Teratogens
- Assisted reprod techniques
What teratogens can cause SGA babies?
- warfarin
- anticonvulsants
- antineoplastic agents
- folic acid antagonists
- tobacco
- alcohol
The finding of symmetric FGR <20weeks suggests what as the cause?
Aneuploidy, most commonly trisomy 18
Do SGA babies delivered at term act more like Pre-term babies or normal birth weight babies
Like normal birth weight babies of the same Gest age
Eg; they feed hungrily, are active and lose little weight in the first few days.
*** they do have some risks similar to preterm infants including poor temp regulation, low infection resistance, increased risk of IU death, hypoxia during labour and early hypoglycaemia
What are the resulting complications of SGA in pregnancy?
- Preterm delivery
- perinatal asphyxia
- impaired thermoregulation
- Hypoglycaemia
- Jaundice
- Feeding problemds
- poor infection resistance
- polycythaemia +inc viscosity
- infant mortality
Long term complications for baby with SGA?
- Perinatal mortality
- reduced physical growth
- Cerebral palsy
- Poorer neurodevelopment and cognition impairment
- CAD, HTN, CKD as an adult
Limitations of FUndal Height?
BMI >35
USS reccomended in 3rd trimester
Ultrasound in Pregnancy: when is it done and what does it measure?
- Biparietal Diameter
- Head circumference
- Abdominal Circumference
- Femur length
Measured 20 weeks, no more then 2-3 weeks apart
What is the first thing to become reduced in SGA that can be identified on a GROW chart
AC; Abdominal circumference
What things do customised growth charts take into account?
Maternal information: maternal height, booking weight, ethnicity
How do you measure Fundal Height?
- Ask woman to empty bladder prior to examination
- Palpate for fundus of uterus with both hands from the xiphisternum and secure nonelastic tape at 0cm with hand
- Bring tape down along longitudinal axis of uterus to upper edge of pubic symphysis and read in centimetres
A shorter Fundal height measure can be due to?
- The fetal head descending into the pelvis
- SGA
- Transverse lie
- oligohydraminos
A longer Fundal height measure can be due to?
- Multiple pregnancies
- LGA
- polyhydraminos
- Breech
How can maternal weight impact fundal height measures?
>100kg can impact the accuracy of the fundal height
What is the most avoidable cause of SGA
Smoking
***there is a smokefree pregnancy service***
What to do when a fetus is identified as SGA
- ASPIRIN
- Reduce maternal risk factors – monitor BP, smoking cessation, blood sugar control
- Fetal surveillance – Via weekly clincal checks and fortnightly growth scans
- as there are no current treatments for SGA, optimal management aims to achieve delivery of the infant in the best possible condition, balancing the risks of prematurity against the risks of the in-utero environment.
What are the four things we monitor in an SGA baby
- Fetal movement monitoring – reduced fetal movements (RFM) often precede fetal death. Although there is no evidence to support keeping formal kick charts, it is recommended that all women with known SGA fetuses are advised to report any change in their normal fetal movement patterns
- Growth scan
- Amniotic fluid assessment – low amniotic fluid is associated with increased perinatal morbidity. Abnormal is <5cm
- Umbilical artery Doppler – primary tool of surveillance for SGA. During normal pregnancy, resistance in the umbilical circulation falls and blood flow velocities increase with advancing gestation. Abnormal umbilical Doppler waveforms, esp absent or reversed-end diastolic velocity, are associated with major placental abnormalities. Doppler flow indices expressed as resistance index (RI)
When should an SGA baby be delivered?
- See figure, +/- steroids
- Vaginal birth should be encouraged unless there is absent or reversed EDF, >>> LCSC
- Continuous CTG monitoring reccomended, if fetal deterioration occurs >>> LCSC
