2.4 | Follow-up assessments of physical and
neurobehavior development
Infants participated in a follow-up survey 2~3 years
after birth. Telephone interviews with parents were performed to record
information on the timing of first walking and speaking. The infant’s
neurobehavioural development was also assessed through phone interviews
using the Questionnaires of Infant Ages and Stages third edition (ASQ-3)
encompassed five developmental domains: communication, gross motor, fine
motor, problem-solving, and personal social, with a maximum of 60 scores
for each domain. Physical evaluation of each twin included height and
weight, which were measured based on the WHO’s standards, and were
conducted by qualified physicians. The height and weight measurements
were standardized by two z-scores of height-for-age and weight-for-age
according to the WHO Anthro program (V.3.2.2) for children five years of
age or younger.