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Table 3 Neurodevelopmental outcomes, perinatal and socio-demographic characteristics of infants conceived by MAR and naturally (means, p-values)

From: Effect of medically assisted reproduction (MAR) and pregnancy planning on Bayley-III Screening Test subscales in preterm infants at 12 months of corrected age: a cross-sectional study

  Mean subscale scores p-values (test statistics)
  MAR
(n = 47)
Natural conception (n = 124) Mann–Whitney test
p-value (U)
t-test
p-value (t)
Neurodevelopmental outcomes
 Cognitive Subscale 17.10 16.76 0.065 (2393.0) 0.172 (1.371)
 Receptive Language Subscale 12.00 11.26 0.004 (2096.5)* 0.003 (3.076)*
 Expressive Language Subscale 11.21 10.70 0.101 (2449.0) 0.111 (1.603)
 Fine Motor Subscale 12.55 12.34 0.320 (2632.5) 0.441 (0.772)
 Gross Motor Subscale 16.02 15.14 0.004 (2114.5)* 0.004 (2.893)*
  Perinatal and socio-demographic characteristics p-values of t-tests or χ^2 tests  
Perinatal data
 Gestational age (weeks), n (%)    0.135  
  very early (< 28 weeks) 2 (4.25) 18 (14.51)   
  early (28–31 weeks) 8 (17.02) 20 (16.12)   
  moderate (32–33 weeks) 16 (34.04) 26 (20.96)   
  late (34–36 weeks) 21 (44.68) 60 (48.38)   
 Birth weight (g), n (%)    0.017*  
  LBW (1500–2499 g) 34 (72.34) 74 (59.67)   
  VLBW (1000–1499 g) 12 (25.53) 26 (20.96)   
  ELBW (< 1000 g) 1 (2.12) 24 (19.35)   
 Mode of delivery, n (%)    0.234  
  Sectio caesarea 36 (76.59) 82 (66.12)   
  Per vias naturales 11 (23.40) 40 (32.25)   
 Apgar scores, M ± SD
  1 min 8.11 ± 1.34 7.51 ± 1.68 0.037*  
  5 min 9.16 ± 0.81 8.67 ± 1.16 0.03*  
  10 min 9.5 ± 0.58 9.19 ± 0.76 0.069  
 Intensive care    0.516  
  NICU-admission, n (%) 41 (87.23) 102 (82.25)   
  Sub-intensive care, n (% 5 (10.63) 14 (11.29)   
 Chronic neonatal morbidities, n (%)
  BPD 0 12 (9.67)  
  ROP 0 6 (4.83)  
  IVH 2 (4.25) 3 (2.41)  
  NEC 1 (2.12) 0  
  PDA 1 (2.12) 11 (8.87)  
  ASD 0 2 (1.61)  
  VSD 0 2 (1.61)  
Socio-demographic data
 Maternal age at childbirth (years), M ± SD 32.78 ± 4.61 30.04 ± 6.44 0.003*  
 Maternal education, n (%)    0.035*  
  Primary 2 (4.25) 22 (17.74)   
  Secondary technical education 4 (8.51) 21 (16.93)   
  Secondary vocational education 6 (12.76) 20 (16.12)   
  Secondary grammar education 5 (10.63) 14 (11.29)   
  College 15 (31.91) 23 (18.54)   
  University 14 (29.78) 19 (15.32)   
 Marital status, n (%)    0.030*  
  Single 0 9 (7.25)   
  Married 34 (72.34) 71 (57.25)   
  Cohabiting 12 (25.53) 27 (21.77)   
  In a relationship 0 11 (8.87)   
 Social status, n (%)    0.043*  
  Above-average 26 (55.31) 42 (33.87)   
  Average 15 (31.91) 61 (49.19)   
  Below-average 6 (12.76) 11 (8.87)   
  1. * p < 0.05, in case of t-test either the independent sample one or the Welch statistic. Note that for some variables the joint frequencies are very low or equal to zero in several (too many) cells, hence the test and its p-value would not be meaningful in case of such an asymptotic test. In these cases (denoted by –) we omit to show the p-values