Table 1

Comparison of perinatal and childhood variables between children formally evaluated at 11 years and non-responders in 2006 birth cohort

VariablesChildren assessed at 11 years (n=200)Children not assessed at 11 years (n=831)P value
Gestational age
 22 weeks% (n/N)0.0% (0/200)0.4% (3/831)0.536
 23 weeks% (n/N)7.5% (15/200)5.8% (48/831)
 24 weeks% (n/N)14.0% (28/200)17.9% (149/831)
 25 weeks% (n/N)34.5% (69/200)32.7% (272/831)
 26 weeks% (n/N)44.0% (88/200)43.2% (359/831)
Birth weight (g)Mean (SD)810.2 (147.5) (n=200)794.5 (149.0) (n=831)0.181
Birth weight z scoresMean (SD)−0.2 (0.8) (n=200)−0.3 (0.8) (n=828)0.163
Male sex% (n/N)50.0% (100/200)48.0% (399/831)0.614
Multiple birth% (n/N)24.5% (49/200)24.0% (202/841)0.886
Ethnicity
 White% (n/N)59.6% (118/198)67.0% (549/819)0.009
 Asian% (n/N)16.2% (32/198)8.7% (71/819)
 Black% (n/N)18.7% (37/198)20.5% (168/819)
 Other% (n/N)5.6% (11/198)3.8% (31/819)
Maternal age at deliveryMean (SD)30.7 (6.0) (n=200)28.7 (6.6) (n=830)<0.001
IMD at birthMean (SD)4.5 (2.7) (n=198)4.3 (2.9) (n=824)0.287
Maternal heightMean (SD)163.0 (6.8) (n=179)162.7 (7.0) (n=652)0.570
Maternal weightMean (SD)69.1 (16.3) (n=172)68.2 (16.5) (n=640)0.572
Breast milk at any time% (n/N)98.5% (197/200)95.7% (794/830)0.059
Breast milk at discharge% (n/N)56.0% (112/200)39.3% (325/828)<0.001
No previous birth ≥24 weeks% (n/N)54.8% (109/199)52.5% (434/827)0.560
Worst cerebral ultrasound scan% (n/N)18.6% (37/199)21.6% (179/827)0.343
Antenatal systemic steroids% (n/N)86.0% (172/200)87.7% (718/819)0.525
Postnatal systemic steroids% (n/N)16.5% (33/200)15.0% (125/831)0.607
Cervical suture% (n/N)8.0% (16/199)5.8% (48/830)0.236
Parenteral nutrition% (n/N)100.0% (200/200)99.9% (830/831)0.624
Days to parenteral nutritionMedian (range)1 (0–6) (n=198)2 (0–14) (n=830)0.116
Enteral feeding begun before day 7% (n/N)87.5% (175/200)82.2% (682/830)0.070
Days to enteral feedingMedian (range)3 (0–24) (n=200)3 (0–34) (n=830)0.006
Feeding difficulties at 3 years% (n/N)22.2% (34/153)16.1% (68/423)0.088
Severe neurodevelopment disability at 3 years% (n/N)10.5% (16/153)14.4% (61/423)0.217
  • *1031 children survived to 3 years, among which 200 children were assessed at 11 years.

  • IMD, Index of Multiple Deprivation.