The effects of intrauterine growth on physical and intellectual development of one-year-old infants: a study on monochorionic twins with selective intrauterine growth restriction

Figures & data

Table 1. Compare the characteristics of sIUGR at birth.

	H-twin (n = 31)	L-twin (n = 31)	χ^2/T	p
Birthweight, g (SD)^a	2394.52 ± 470.83	1693.23 ± 395.15	29.5	<.001*
Length, cm^a	44.42 ± 4.60	40.74 ± 5.67	232.5	<.001*
Head circumferences, cm^a	32.16 ± 1.96	29.95 ± 2.11	228.5	<.001*
Body BMI (kg/m^2)^a	12.16 ± 1.96	10.25 ± 1.83	223.0	<.001*
Apgar 1 min^a	9.26 ± 0.73	9.26 ± 0.82	0.000	1.000
Apgar 5 min^a	9.81 ± 0.42	9.87 ± 0.43	–3.5	.688
Turn the NICU (%)^b	19 (61.3)	27 (87.1)	1.897	.058
Average length of stay (days)^c	4.0 (0.0, 13.0)	8.0 (3.0, 29.0)	–165.0	<.001*
Low birth weight (LBW), n (%)^b	13 (41.9)	28 (90.3)	3.873	<.001*
Velamentous placenta, n (%)^b	3 (9.7)	14 (45.2)	3.317	.001*
Neonatal hypoglycaemia, n (%)^b	2 (6.5)	11 (35.5)	1.941	.052

H-twin group: high birthweight-twin group; L-twin group: low birthweight-twin group; SD: standard deviation; BMI: body mass index; LBW: low birth weight.

*p < .05.

^a Paired t-test.

^b χ^2-test.

^cWilcoxon’s rank sum test.

Figure 1. The physical growth data of 31 pairs of sIUGR twins. 

Table 2. The rate of physical growth data of two groups.

Months		1	3	6	8	12
Weight (kg)	H-twin	0.7 ± 0.3	1.6 ± 0.5	2.3 ± 0.7	2.7 ± 0.8	2.7(2.5,3.5)
	L-twin	0.7 ± 0.3	2.0 ± 0.5	3.1 ± 0.8	3.5 ± 1.0	3.8(3.5,4.8)
	T/Z	–1.6^a	–5.2^a	–9.7^a	–12.1^a	–181.0^b
	p	.112	<.001*	<.001*	<.001*	<.001*
Height (cm)	H-twin	0.1(0.1,0.2)	0.3(0.3,0.4)	0.5(0.4,0.5)	0.6 ± 0.2	0.6(0.6,0.8)
	L-twin	0.2(0.1,0.2)	0.4(0.3,0.4)	0.5(0.4,0.6)	0.7 ± 0.2	0.6(0.6,0.8)
	T/Z	–27.5^b	–110.0^b	–177.0^b	–3.9^a	–231.0^b
	p	.580	.029*	<.001*	<.001*	<.001*
BMI (kg/m^2)	H-twin	0.2(0.1,0.3)	0.4 ± 0.2	0.5 ± 0.3	0.5 ± 0.2	0.5 ± 0.2
	L-twin	0.3(0.1,0.5)	0.6 ± 0.3	0.7 ± 0.4	0.7 ± 0.4	0.6 ± 0.4
	T/Z	–86.0^b	–2.7^a	–3.9^a	–3.7^a	–4.7^a
	p	.092	.010*	<.001*	.001*	<.001*
Head circumference (cm)	H-twin	0.1 ± 0.1	0.2 ± 0.1	0.3 ± 0.1	0.4 ± 0.1	0.4 ± 0.1
	L-twin	0.1 ± 0.0	0.3 ± 0.1	0.4 ± 0.1	0.4 ± 0.1	0.5 ± 0.1
	T	0.4^a	–3.9^a	–4.2^a	–6.9^a	–5.7^a
	p	.724	.001*	<.001*	<.001*	<.001*

H-twin group: high birthweight-twin group; L-twin group: low birthweight-twin group; BMI: body mass index.

The rate of physical growth was calculated as follows: (physical indicators for each month – birth)/birth)×100.

*p<.05.

^at-test.

^b Wilcoxon’s rank-sum test.

Table 3. Bayley scales assessment results for L-twin vs. H-twin.

	H-twin (n = 31)	L-twin (n = 31)	T/Z	p
PDI	104.2 ± 15.2	96.1 ± 17.7	4.7^a	<.001*
MDI	95.0 (77.0, 103.0)	93.0 (78.0, 101.0)	99.0^b	.039*

*p<.05.

H-twin group: high birthweight-twin group; L-twin group: low birthweight-twin group; PDI: psychomotor development index; MDI: mental development index.

^a t-test.

^b Wilcoxon’s rank sum test.