SGA in Pregnancy

Question 1

When do you first start feeling fetal movements?

Answer 1

Primiparous: 18-20wks

Multiparous: 15-16wks

Question 2

From what week gestation does fetal movement become a reliable indicator of fetal wellbeing?

Answer 2

Post 28weeks gestation

However we still reccommend women begin to track the fetal movement past 18 weeks to become familiar with the pattern

Question 3

What is reduced/absent fetal movements associated with?

Answer 3

fetal death/stillbirth

Question 4

What is the definition of SGA?

Answer 4

Babies that track below the 10^th centile for birthweight for their gestational age, as defined by their sex/ethnicity adjusted GROW chart

Question 5

What are the two main patterns of growth restriction?

Answer 5

1. Asymmetric:
   
   • When abdo growth is disproportionately low when compared with the head (head circumference)
2. Symmetric “global growth restriction”
   
   • all measurements are small (biparietal diameter, head circumference, abdo circum, femur length)

Question 6

When does asymmetric growth of a fetus usually occur and what are the common causes?

Answer 6

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

Question 7

When does Symmetric growth of the fetus occur and what are the common causes

Answer 7

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)

Question 8

Asymmetric fetal growth can increase the risk of?

Answer 8

Fetal hypoxia and fetal hypoglycaemia

Question 9

When does being a twin start to impact on growth?

Answer 9

Only >30-32 weeks will being a twin slow and reduce the growth from the norm,

Question 10

Pre-natal risk factors of SGA?

Answer 10

• Smoking
• Underweight
• >>>maternal age
• asian/indian
• Nulliparity
• Mother born SGA
• cocaine
• Chronic HTN
• CKD
• Anti-phospholipid
• Malaria
• Pre-gest DM

Question 11

Antenatal risk factors for SGA

Answer 11

• Heavy bleeding in early pregnancy
• Placental abruption
• Pre-eclampsia
• Gest HTN
• Gest DM

Question 12

Common Causes of SGA:

Answer 12

• 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

Question 13

What teratogens can cause SGA babies?

Answer 13

• warfarin
• anticonvulsants
• antineoplastic agents
• folic acid antagonists
• tobacco
• alcohol

Question 14

The finding of symmetric FGR <20weeks suggests what as the cause?

Answer 14

Aneuploidy, most commonly trisomy 18

Question 15

Do SGA babies delivered at term act more like Pre-term babies or normal birth weight babies

Answer 15

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

Question 16

What are the resulting complications of SGA in pregnancy?

Answer 16

• Preterm delivery
• perinatal asphyxia
• impaired thermoregulation
• Hypoglycaemia
• Jaundice
• Feeding problemds
• poor infection resistance
• polycythaemia +inc viscosity
• infant mortality

Question 17

Long term complications for baby with SGA?

Answer 17

• Perinatal mortality
• reduced physical growth
• Cerebral palsy
• Poorer neurodevelopment and cognition impairment
• CAD, HTN, CKD as an adult

Question 18

Limitations of FUndal Height?

Answer 18

BMI >35

USS reccomended in 3rd trimester

Question 19

Ultrasound in Pregnancy: when is it done and what does it measure?

Answer 19

• Biparietal Diameter
• Head circumference
• Abdominal Circumference
• Femur length

Measured 20 weeks, no more then 2-3 weeks apart

Question 20

What is the first thing to become reduced in SGA that can be identified on a GROW chart

Answer 20

AC; Abdominal circumference

Question 21

What things do customised growth charts take into account?

Answer 21

Maternal information: maternal height, booking weight, ethnicity

Question 22

How do you measure Fundal Height?

Answer 22

• 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

Question 23

A shorter Fundal height measure can be due to?

Answer 23

• The fetal head descending into the pelvis
• SGA
• Transverse lie
• oligohydraminos

Question 24

A longer Fundal height measure can be due to?

Answer 24

• Multiple pregnancies
• LGA
• polyhydraminos
• Breech

Question 25

How can maternal weight impact fundal height measures?

Answer 25

>100kg can impact the accuracy of the fundal height

Question 26

What is the most avoidable cause of SGA

Answer 26

Smoking

***there is a smokefree pregnancy service***

Question 27

What to do when a fetus is identified as SGA

Answer 27

1. ASPIRIN
2. Reduce maternal risk factors – monitor BP, smoking cessation, blood sugar control
3. 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.

Question 28

What are the four things we monitor in an SGA baby

Answer 28

1. 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
2. Growth scan
3. Amniotic fluid assessment – low amniotic fluid is associated with increased perinatal morbidity. Abnormal is <5cm
4. 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)

Question 29

When should an SGA baby be delivered?

Answer 29

• 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