Presentation in Florence, JUne 2014 at European Perinatal Conference

1. Customized birthweight centiles
in application to Polish data
Katarzyna Szamotulska, Ewa Mierzejewska,
Tomasz Maciejewski, Michal Troszynski

2. INTRODUCTION
Poland does not have population growth charts for
newborns based on Polish data.
It constraints studying the processes and risk factors
leading to Fetal Growth Restriction (FGR).
Therefore estimation of customized birthweight centiles
as proposed by Gardosi may be important for better
understanding, prevention and treatment of FGR in the
country.

3. CONCEPT
• Gardosi J., Chang A., Kalyan B., Sahota D., Symonds
EM. Customized antenatal growth. Lancet 1992; 339:
283-287
• Gardosi J. Intrauterine growth restriction: new standards
for assessing adverse outcome. Best Practie &
Reserach Clinical Obstetrics and Gynecology 2009; 23:
741-9
• Hadlock F.P. , Harrist RB., Martinez-Poyer j. et al. In
utero analysis of fetal growth: a sonographic weight
standard. Radiology 1991;181:129-133
• www. perinatal.org.uk, www. gestation.net

4. EXPECTED TERM OPTIMAL WEIGHT
(E(TOW))
E(TOW)=
0constant +1maternal height+
2maternal weight+3maternal weight2+4maternal weight3
+5parity1+6parity2+7parity3+8sex

5. MATERIAL AND METHODS
One thousand two hundred
deliveries in 8 hospitals in
south-eastern and central
Poland were observed in 2013
(150 consecutive deliveries per
hospital) based on medical
records and interview with the
mother after delivery.
Estimation of regression
equation for optimal weight of a
baby was based on data
available for maternal height,
maternal weight before
pregnancy, parity and sex of
the child (n=945).

6. MATERIAL AND METHODS
Gestational age was centered around mean of 275 days
from first day of the last menstrual period, maternal
height – around mean of 166 cm, maternal weight before
pregnancy – around mean of 64 kg.
Parity was categorized as 0,1,2+.
The tenth percentile was set up at expected birthweight
minus 14% (centile limits based on expected optimal
weight)

7. MATERNAL CHARACTERISTICS
BY HOSPITALS
170
168
166
164
162
160
Height (cm)
Z R L P G NS K W
70
68
66
64
62
60
Pre-pregnancy weight (kg)
Z R L P G NS K W
30%
25%
20%
15%
10%
5%
0%
Parity 3+
Z R L P G NS K W
80%
60%
40%
20%
0%
Boys
Z R L P G NS K W
Height (cm)
Parity 3+
Pre-pregnancy weight (kg)
Boys

8. FORMULA FOR ADJUSTING
EXPECTED TERM OPTIMAL WEIGHT
(E(TOW))
E(TOW)=
0constant +1maternal height+
2maternal weight+3maternal weight2+4maternal weight3
+5parity1+6parity2+7parity3+8sex

9. RESULTS
Mean estimated birth weight was 3883 ±343 g and was
equal to mean observed birth weight.
Estimated parameters of the model were similar to
parameters from other populations.

10. ESTIMATED PARAMETERS
OF GARDOSI MODEL
Maternal characterstics Current study
(n=945)
Nottingham
(n=38,114)
EUROPOP
(n=7,615)
Warsaw
(n=1,019)
Constant 3405.0 3478.4 3401.6 3308.6
Maternal height 6.9 7.8 8.8 7.2
Maternal weight 9.8 8.7 7.2 14.2
Maternal weight2 -0.108 -0.117 -0.135 -0.188
Maternal weight3 -0.003 0.00072 0.0014 0.005
Parity 0 Ref. Ref. Ref. Ref.
Parity 1 100 108 87 135
Parity 2+ 80 149 148 142
Parity 3 x 150 128 393
Parity 4 x 150 140 x
Sex of child (male) 154 116 132 156
Smoking<10 cig./d. x -153 -157
Smoking 10-19 cig./d. x -215 -128 -130
Smoking>=20 cig./d. x -246 -182

11. CUSTOMIZED NORMS VS. CLINICAL
DIAGNOSIS OF HYPOTROPHY
In comparison to clinical diagnosis of fetal hypotrophy,
customized birthweight 10 centile calculated according
to Gardosi method was ascertained in 91.7% cases of
fetal hypotrophy noticed in medical records and in 10.6%
cases of fetal hypotrophy not noticed in medical records.
Customized norms
10
percentile
>10
percentile
Total
Clinical
diagnosis
of
hypotrophy
Yes 11 (91.7%) 1 (8.3%) 12 (1.3%)
No 99 (10.6%) 834 (89.4% ) 933 (98.7%)
Total 110 (11.6%) 835 (88.4%) 945(100%)

12. RESULTS
Observed birthweight below the 10th percentile of
expected birthweight was related to smoking before
pregnancy (OR=1.79, p=0.013) and low socioeconomic
status (OR=1.88, p=0.015)

13. HYPOTROPHIC CHILDREN
NOT ASCERTAINED BY CUSTOMIZED NORMS
Neither
(n=834)
Cust. only
(n=99)
Both
(n=11)
Prematurity 5.8% 7.1% 27.3%
Overweight
26.0% 35.4% 9.1%
and obesity
PIH 2.3% 2.0% 9.1%
Eclampsia 0.7% 0.0% 9.1%
GDM 2.5% 5.1% 0.0%

14. NICU ADMISSION
The risk of NICU admission in children without clinical
diagnosis of hypotrophy was three-fold higher in case of
customized birthweight  10 centile vs. customized
birthweight > 10 centile .
2.7%
9.9%
0.0%
36.4%
50%
40%
30%
20%
10%
0%
Neither Only customized
norm
Only clinical
diagnosis
Both

15. CONCLUSIONS
Customized birthweight centiles are useful for
estimation of fetal growth restriction in Polish population
and enable prediction of negative newborn outcomes.