Abstract:

Objective: To describe the growth velocity percentile curves under breast feeding for 3 months for healthy breastfed infants aged 1 to 2 months, which can provide a more comprehensive reference for the evaluation of infant growth and development. Methods: A multi-center randomized clinical trial was performed. 1~2 months old infants (gestational age ≥37 weeks) fed with formula milk only for mothers' own problems presented in child health clinics of six study settings were included in formula powder group (and then randomly assigned to commercially available formula subgroup 1 or 2); In the same study setting, 1~2 months old infants (gestational age ≥37 weeks) with exclusively breast feeding matched by gender and body weight with formula powder group were included in breast feeding group. The primary outcomes were growth velocity of height, body weight and head circumference at 1, 2 and 3 months. The monthly growth velocity was equal to ［(measured value at this actual follow-up time measured value at last actual follow up time) / (this actual follow-up time the last actual follow up time)d］ ×30. The secondary outcomes were ①the stool character and defecation frequency at the enrolment and 1, 2 and 3 months after enrolment. The parents collected fresh stool and snapped photos on their phones and the stool characters were judged according to Bristol stool shape chart. ②Incidence of adverse events and serious adverse events over the trial period. Full analysis set (FAS) for effectiveness analysis and evaluation of defecation frequency and stool character and safety set (SS) for adverse events were performed. The coefficient of skewness median coefficient of variation (LMS) method was applied to calculate smoothed height, body weight and head circumference percentiles (P3、P5、P10、P25、P50、P75、P90、P95、P97) at 1, 2, 3 months by LMS software. Results: From May 6, 2016 to October 30, 2016, 152 infants were included in formula powder group and 72 in breast feeding group respectively (SS). The numbers of drop-out were 24 in formula powder group and 3 in breast feeding group. The numbers of participants included in FAS were 128 for formula powder group and 69 for breast feeding group respectively. There was no significant difference in gender, day age at enrolment, height, body weight, gestational age and delivery mode between two groups (FAS). ①In breast feeding group, the growth velocity of height was 3.1±1.4 cm at 1 month, 3.0±0.8 cm at 2 months and 2.7±0.6 cm at 3 months, which showed a downward trend month by month; the growth velocity of body weight was 951±371 g at 1 month, 824±278 g at 2 months and 749±219 g at 3 months, which showed a downward trend month by month; the growth velocity of head circumference was 1.5±0.7 cm at 1 month, 1.4±0.5 cm at 2 months and 1.3±0.3 cm at 3 months, which showed a slow downward trend month by month. ② No significant difference was found between formula powder group and breast feeding group in the growth velocity of height, body weight and circumference at 1, 2 and 3 months respectively. The growth velocity of height, body weight and circumference in formula powder group also showed a downward trend month by month. ③There was significant difference in both defecation frequency and stool character at enrolment, 1, 2 and 3 months between formula powder group and breast feeding group. ④None of adverse events was considered directly attributable to formula powder or breast feeding in totally 224 infants during the study period. Conclusion: The growth velocity of height, body weight and head circumference under breast feeding for 3 months of Chinese healthy breast feeding infants aged 1~2 months showed showed a downward trend month by month. The downward change month by month of growth velocity in head circumference was slower than that of height and body weight.The growth velocity trend in formula powder feeding infants was similar to that in breast feeding infants.