1. Fetal Growth Patterns: how to improve the antenatal detection of the Small or Large for gestational age fetus in a low risk population
Dr Alison Munt
Obstetrician and Gynaecologist
Lyell McEwin Hospital, Elizabeth Vale.
Adelaide Obstetrics, Goodwood.
Introduction
Ask questions at any stage and ill endeavour to answer them

2. Fetal Growth Patterns What is considered Abnormal fetal growth
Small for gestational age (SGA)/intrauterine growth restriction (IUGR)
Large for gestational age (LGA)/macrosomia
Increased morbidity and mortality
Antenatal Assessment of risk factors
Detection/screening
Abdominal palpation/SFH measurements
Customised SFH chart
Indications for referral
How to manage a patient SGA/LGA fetus

3. Normal Fetal Growth
Defined as the expression of the genetic potential to grow in a way that is neither constrained nor promoted by internal or external factors (SA perinatal Practice Guidelines)
Normal singleton fetal growth (Resnik 2002)
5g/day at 14-15weeks
10g/day at 20w
30-35g/day at weeks
Rule of thumb in third trimester is 200g a week expected growth.

4. Small for Gestational Age (SGA)
Birthweight below the 10th centile of weight for gestation. This does not necessarily indicate fetal growth restriction (SA Perinatal Practice Guidelines)

5. Intrauterine Growth Restriction (IUGR)
a condition in which a fetus is unable to achieve its genetically determined potential size.
This functional definition seeks to identify a population of fetuses at risk for modifiable but otherwise poor outcomes.

6. Not all SGA fetuses are IUGR (visa versa)
40% constitionally small
Only 40% of SGA babies benefit from intervention
Not all fetuses that are SGA are pathologically growth restricted and, in fact, may be constitutionally small. Similarly, not all fetuses that have not met their genetic growth potential are in less than the 10th percentile for estimated fetal weight (EFW).
Intrinsically small chromosomal or environmental etiology- not benefit from intervention
Only 40% of SGA babies benefit from intervention

7. Large for Gestational Age/Macrosomia
Interchangeable terms
fetal growth beyond a specific weight, usually 4,000 g or 4,500 g regardless of the fetal gestational age.
Results from large cohort studies support the use of 4,500 g as the weight at which a fetus should be considered macrosomic.
Weighing the newborn after delivery is the only way to accurately diagnose macrosomia.

8. Fetal Growth Patterns INCREASED MORBIDITY AND MORTALITY
Why screen for SGA and LGA babies: Small (and large) for gestational age babies are at an increased risk of associated morbidity and mortality.

9. Morbidity associated with IUGR
Meconium stained liquor
Abnormal heart rate patterns intrapartum
Intrauterine fetal death
Hypoxic ischaemic encephalopathy
Poor neurological development
Delay in cognitive development
Sudden infant death syndrome

10. Morbidity associated with IUGR
In adult life
Type 2 diabetes and
hypertension (RCOG 2002)
mental health problems
Children born below 2nd percentile at increased risk: (Zubrick etal)
mental health morbidity (OR 2.9; 95% CU, )
Academic impairment (OR, 6; 95% CI, )
Poorer general health (OR, 5.1; 95% CI, )
Increasingly, data support the idea that long-term consequences of IUGR last well into adulthood. Several authors have noted that these individuals have a greater predisposition to develop a metabolic syndrome later in life, manifesting as obesity, hypertension, hypercholesterolemia, cardiovascular disease, and type 2 diabetes. Several hypotheses have been proposed to explain this relationship. Hales and Barker proposed the so-called thrifty phenotype in This idea suggests that intrauterine malnutrition results in insulin resistance, loss of pancreatic beta-cell mass, and an adult predisposition to type 2 diabetes
In a study performed in Western Australia, Zubrick et al showed that children born below the second percentile for weight were at significant risk for mental health morbidity (odds ratio, 2.9; 95% CI, ), academic impairment (odds ratio, 6; 95% Cl, ), and poorer general health (odds ratio, 5.1; 95% Cl, ).[9] Specifically, Tideman et al have shown that impaired fetal circulation, as demonstrated by Doppler studies, in association with IUGR, results in worsened cognitive function in adulthood.[10] Tideman E etal 2007

11. Morbidity associated with LGA
Maternal risks:
Protracted or arrested labour
Operative vaginal delivery
Caesarean delivery
Genital tract lacerations
Postpartum haemorrhage
Uterine rupture
Fetal and neonatal risks:
Shoulder dystocia leading to birth trauma (brachial plexus injury, fracture) or asphyxia
Neonatal hypoglycemia
RiskACOG emphasizes that an increased risk of cesarean delivery is the primary maternal risk factor associated with macrosomia. Results from cohort studies demonstrate that the risk of cesarean delivery in women attempting a vaginal delivery at least doubles when the fetal weight is estimated to be more than 4,500 g.
Although rare (complicating 1.4 percent of all vaginal deliveries), shoulder dystocia is the most serious complication associated with fetal macrosomia. When birth weight is more than 4,500 g, however, the risk is increased to 9.2 to 24 percent in pregnant women without diabetes and to 19.9 to 50 percent in pregnancies complicated by diabetes. However, while macrosomia increases risk, shoulder dystocia also occurs unpredictably in infants of normal birth weight.
Fracture of the clavicle and damage to the nerves of the brachial plexus are the most common fetal injuries associated with macrosomia. In macrosomic infants, the risk of clavicular fracture and brachial plexus injury is approximately 10-fold and 18- to 21-fold, respectively, when birth weight is more than 4,500 g.
s of macrosomia

12. Morbidity associated with LGA
Long-term risks in offspring:
Development of impaired glucose tolerance and obesity
Development of metabolic syndrome
Increase in aorta intima-media thickness, left ventricular mass, and abnormal lipid profile

13. Detection: Antenatal care
Is fetus growing at a normal rate = according to its genetic potential?
Abdominal palpation
Measurement of SFH
BUT FIRST:
Identify those patients not suitable for low risk care or routine screening
Who are the patients that require additional screening ie. Serial USS

14. Identiftying High Risk Patients
At risk of IUGR
Multiple pregnancy
Previous hx of IUGR
Previous hx of Unexplained stillbirth
Hypertension/past hx of PET
Antiphospholipid syndrome
Autoimmune disease
Renal conditions
Diabetes
Maternal age 40+
Alcohol, drug misuse

15. Identiftying High Risk Patients
At risk of macrosomia
High body mass index
Multiparity
Advanced maternal age
Maternal diabetes
Post term pregnancy
Male infant
Previous macrosomic infant
Excessive weight gain in pregnancy
Maternal birth weight over 4000 grams

16. Indications for serial growth USS monitoring
Increased risk based on an antenatal assessment
Risk factors mentioned
PAPPA low (<0.4)
Single umbilical artery on morphology
Fundal Height measuring not possible/unreliable
Polyhydramnios
High BMI (35+)
Large fibroids

17. Detection: Antenatal care
Is fetus growing at a normal rate = according to its genetic potential?
Abdominal palpation
Measurement of SFH
Antenatal detection of both the large fetus and the small fetus can possible reduce the morbidty and mortlaity that is associated with abnormal growth patterns.

18. Abdominal Palpation: Leopold’s Maneurvers
Factors that contribute
to the limited predictive
Value of SFH measurement:
Maternal obesity
Large fibroids
hydramnios
Fetal lie
Head engagement
a: fundal grip
b: umbilical grip
c: pawlick’s grip
d: pelvic grip
Maternal obesity, abnormal fetal lie, large fiborids, hydramnios and fetal head engagtement contribute to the limited predictive accuracy of SFH measurement. Important to assess for these things.

19. Abdominal Palpation
Limited accuracy in the detection of a SGA neonate in low risk populations
Low risk populations (Bais etal 2004)
sensitivity 19-21%, specificity 98%
In mixed risk populations,
the sensitivity increases to 32-44% (Hall etal 1980; Rosenberg etal 1982)
In high risk populations
53% for severe SGA (Bias etal 2004)

20. Fundal Height Measurement

21. Current SA guideline:
The woman should be lying in the supine position with her head supported on a single pillow. The couch should be flat
Measure from the highest point of the fundus to the top of the symphysis pubis.
Begin measuring from the fundus since this is the more variable end point.
Measure with the tape scale facing downwars so that you are less influenced by previous results.
Measurements should be recorded to the nearest 0.5 centimetre.
WHO DOES ACTUALLY FOLLOW THE SA GUIDELINE??

22. Single FH measurement approach
“The fetus is most likely AGA if FH = Dates +/-2 cm”
Probably not a satisfactory approach to screening for abn growth paterns
A recent systematic review of five studies highlighted the wide variation of predictive accuracy of FSD measurement for a SGA infant. (NCCWCH 2008)
Although early studies reported sensitivies of 56-86% and specifiecites of 80-93% for SFH detection of a SGA neonate, a large study of 2941 women reported SFH to be less predictive with a sensitivity of 27% and specificity of 88% (LR+ 2.22, 95% CI ; LR- 0.83, 95% CI ).
Maternal obesity, abnormal fetal lie, large fiborids, hydramnios and fetal head engagtement contribute to the limited predictive accuracy of SFH measurement. SFH is associated with signifcant intra- and inter-observere variation and serial measurement may improve predictiv e accuracy.
Antenatal detection rates of SGA fetus (25-30%)

23. Case Primigravida presents at 36+ weeks Uneventful pregnancy
Obstetric examination:
Fetus: longitudinal lie, cephalic presentation
FHR: 145 bpm
Fundal Height: 35.5 cm
What is your estimate of the fetal growth/weight? SGA<P10, AGA:P10-90 or LGA>P90?
Past practise has been to accept a SFH measurement that is within 2cm of the gestational age. Should be reassured by that finding.

24. SFH measurement
SFH is associated with significant intra- and inter-observation variation
Continuity of care provider further improves the accuracy of fetal growth surveillance
serial measurement may improve predictive accuracy.
Even better: Customised SFH charts!

25. FH Chart SA hand held record
Who does actually plot FH in chart?

26. Our case 36 weeks: serial plot population based chart
What is your view about fetal growth/weight? SGA<P10, AGA:P10-90 or LGA>P90?

27. Customised SFH Charts
Evidence that improves detection whilst reducing unnecessary referrals for investigations (Gardosi and Francis 1999; Roex 2012)
Customised antenatal growth charts are now recommended by the RCOG (RCOG guidelines 2002)
Also currently being used in SA hospitals:
Lyell McEwin Hospital Service
Flinders Medical Centre
Jason Gardosi, West Midlands Perinatal Institute,
Birmingham B6 5RQ, UK
Evidence that plotting serial fundal height measurements on individually customised growth charts can significantly improve detection of babies that are growing inappropriately, whilst reducing unnecessary referrals for investigations (Gardosi and Francis 1999; Roex 2012)
Customised antenatal growth charts are now recommended by the RCOG (RCOG guidelines 2002)
Also currently being used in SA hospitals including
LMHS
FMC

28. SA perinatal guidelines

29. Example Customised FH Chart
FUNDAL HEIGHT CM
ULTRASOUND
EST. FETAL WEIGHT
The following data is used to generate these customised charts
Ethnic origin
Maternal height
weight
Parity
Gestation, sex, and
weight of previous
babies in grams
placed in the maternal notes until the morphology scan appointment
Following the morph scan a copy of the customised growth chart will be included in the maternal hand held record to replace the generic chart
Pathological factors known to affect birth weight and growth such as smoking hypertension, diabetes and preterm delivery are excluded
GESTATION WKS

30. Customised SFH charts
Mrs Large
Mrs Small

31. Case Primigravida presents at 36+ weeks Uneventful pregnancy
Obstetric examination:
Fetus: longitudinal lie, cephalic presentation
FHR: 145 bpm
Fundal Height: 35.5 cm
What is your estimate of the fetal growth/weight? SGA<P10, AGA:P10-90 or LGA>P90?

32. Our case 36 weeks: serial plot population based chart
What is your view about fetal growth/weight? SGA<P10, AGA:P10-90 or LGA>P90?

33. Our case: serial FH plot customised chart
What is your view about fetal growth/weight? SGA<P10, AGA:P10-90 or LGA>P90?

34. Comparing trends

35. What about the ‘evidence’?
No randomised controlled trials (Level II)
One cohort trial comparing laying on hands with plotting on customised chart (level III)
One cohort trial comparing non plotting with plotting on customised chart (level III)
No trials comparing customised with non-customised SFH charts
Observational studies suggest that customised SFH charts may improve the detection of a SGA neonate.

36. Serial plotting FH in customised chart
1. West Midlands UK 1999
Improved detection of SGA fetus 29.2% vs 47.9% (OR 2.2; 95% CI ; p 0.03)
Gardosi J and Francis A. BJOG 1999;106(4):309-12
Use of customised charts was also associated with fewer referrals for investigation and fewer admission.
2. Adelaide NALHN 2012
Improved detection rate 24.8% vs 50.6% (OR 3.1; CI ; P<0.001 )
Roex et al Aust N Z J Obstet Gynaecol 2012; 52:78-82.
No trials were indentified that compared customised with non-customised SFH charts and thus evidence for their effectivemeness on outcomes such as perinatal morbidity/mortality is lacking.
However observational studies suggest that customised SFH charts may improve the detetion of a SGA neonate.
In one study, use of customised charts, with referral when a single SFH measurement fell below the 10th centile or the last two measurements were above the 10th centile but the slpe was flatter than the 10th centlie line, resulted in improved sensitivity for a SGA neonate (48% versue 29% OR 2.2, 95% CI ) compared to abdominal palpation. ( Gardosi 1999)
Use of customised charts was also associated wth fewer referrals for investigation and fewer admission. An audit from the West Midlands also showed that the use of customised SFH charts detected 36% of SGA neonates compared with only 16% when customised charts were not used. (Wright etal 2006)

37. When to refer for Growth USS: ‘Fetal GROW’ guideline NALHN
1. Low first fundal
height

38. When to refer for Growth USS: ‘Fetal GROW’ guideline NALHN
2. Static growth

39. When to refer for Growth USS: ‘Fetal GROW’ guideline NALHN
3. Slow growth

40. When to refer for Growth USS: ‘Fetal GROW’ guideline NALHN
4. Accelerated Growth

41. ‘Fetal GROW’ guideline NALHN
ANC visit > 24 wks
PLOT FH in Gardosi Chart
Low first FH
Static growth
Slow growth
Accelerated growth
US Fetal growth
Assess US & Plot EFW in Gardosi Chart
EFW>P10 & US findings 
US EFW <P10
Back to routine care and FH plotting
URGENT REFERRAL
OBSTETRICAL REVIEW

42. Where to find Customised charts
growth charts just download Australian FH charts

43. Improved detection: so what?
? Decreased mortality and morbidity
Stillbirths are the largest contributor to perinatal mortality. They are a central indicator of patient safety
and quality of care, and an essential component of the NHS Outcomes Framework [1].
 West Midlands stillbirth rates have been consistently well above national rates for the last 50 years.
 Recent regional initiatives by the Perinatal Institute, in collaboration with SHA, PCTs and provider Trusts,
have led to significantly fewer stillbirths; this has resulted in West Midland rates falling, for the first time
ever, to below the national average.
 This reduction is due to fewer deaths associated with fetal growth restriction and follows a comprehensive
programme of audit, training, and implementation of protocols to increase antenatal detection of
pregnancies at risk.
 The decrease is most marked in areas which have been at the forefront of implementation, and has led to
reductions which, if extrapolated across the region, would lead to 78 fewer stillbirth each year.
 It is essential that this momentum is maintained and built upon, and that stillbirth prevention remains a
continued priority in the West Midlands.

44. Crude Stillbirht Rates 2000-2009 West Midlands 5
Crude Stillbirht Rates West Midlands 5.74, England and Wales 5.33
 Figure 1 shows crude stillbirth rates since
2000 (3 year moving average) for West Midlands
and England & Wales. Stillbirth rates have been
consistently above the national average since the
earliest available (1963) regional ONS data.
The 10 year average (2000‐2009) West Midlands
rate: 5.74 (CI 5.56‐5.92) is significantly above that
for England & Wales: 5.33 (CI 5.28‐5.39) (Fig 2).

45. Crude stillbirth rates 2000-2011 West Midlands versus England/Wales
Significant drop in West Midlands, Gardosi’s health region 5.02 vs 5.24 / 1000 (p<0.05)
Drop most significant
in areas were
customised FH
charts were
introduced first
Perinatal Institute Birmingham 2011
 Figure 2: There has been a significant (p<0.05)
downward trend in West Midlands stillbirth rates,
while national rates have remained relatively static
This reduction has resulted, for the first time, in
the regional stillbirth rate falling below the
national average in 2011: 5.01 vs 5.24 /1000.
Compared to the expected number based on the
10 year baseline, this drop represents 53 fewer
stillbirths in the West Midlands in 2011.
attributed to increased
efforts in prevention, including the Community
Growth Scanning project (CoGS) [4] commenced
in 2010, which has led to significantly improved
detection of FGR in at‐risk pregnancies [5].

46. Conclusion
In a low risk population serial plotting of the Fundal Height on a customised Gardosi chart combined with ‘GROW guideline’ appears to be the preferred method
Laying hands on or just measuring FH and non plotting = non evidence based practice

47. Surveillance for suspected IUGR
2 weekly growth USS
Weekly USS for AFI and doppler
Weekly CTG
Delivery </= 37 weeks
Mode: often don’t tolerate labour

48. Management of Macrosomia
+ poorly controlled diabetes may lead to early IOL
Evidence supports:
Offering elective LSCS if GDM and EFW >4.5kg or no GDM and EFW >5kg.
No evidence for improved outcomes with IOL (Two systematic reviews concluded that labour induction for suspected fetal macrosomia did not result in a lower rate of shoulder dystocia or caesarean delivery than expectant management)

49. Questions

50. ‘Fetal GROW’ guideline NALHN
ANC visit > 24 wks
PLOT FH in Gardosi Chart
Low first FH
Static growth
Slow growth
Accelerated growth
US Fetal growth
Assess US & Plot EFW in Gardosi Chart
EFW>P10 & US findings 
US EFW <P10
Back to routine care and FH plotting
URGENT REFERRAL
OBSTETRICAL REVIEW