APPENDIX 1

Percentage of MCS Singleton Infants Who Achieved Developmental Milestones by Age in Months and the Proportion of Infants With Developmental Delay

Singleton Infants Who Achieved Development Milestone, %Infants Who Had a Delay, %
n8 mo9 mo10 mo≥11 moAnalysis SampleaExcluded Sampleb
Gross motor coordination
    Infant can sit up without being supported18 27692.4095.7997.9198.682.6211.90
    If infant is put down on the floor, he or she can move about from one place to another18 27687.7892.2893.8996.666.4211.73
    Infant can stand up while holding onto something, such as furniture18 27654.8168.6879.0190.510.170.35
    Infant can walk a few steps on his or her own18 2761.114.009.2421.090.000.00
Fine motor coordination
    Infant grabs objects using the whole hand18 27799.3499.3899.3699.510.521.60
    Infant passes a toy back and forth from one hand to another18 25993.2595.1295.5797.794.406.68
    Infant can pick up a small object using forefinger and thumb only18 22883.3088.8492.2994.181.332.95
    Infant puts his or her hands together18 26675.9983.5689.2694.030.100.23
  • Numbers are the raw values, and percentages are adjusted for the clustered survey design and weighted to the UK population.

  • a Term singleton infants who weighed >2500 g and were not placed in special infant unit and whose mothers were the main respondent.

  • b One or more of preterm, low birth weigh, multiple birth, in special infant unit, and respondent not natural mother.