A Clinical Trial of Infant Formula-fed

1. Sample size：Seventy two cases will be enrolled in breast milk group, 144 cases in formula milk group, 72 cases each in commercially available formula subgroup and Friso formula subgroup with 36 cases each in every hospital (18 male infants and 18 female infants).
2. Observation period：Observational period will maintain 12 weeks. Infants of breast milk group are fed with breast milk before inclusion and during the trial process. In the formula milk groups, if subjects were fed with other formula instead of commercially available formula and Friso formula before inclusion, then a wash-out period of no more than 2 weeks is necessary.
3. Random method: In commercially available formula subgroup and Friso formula subgroup, infants will be included randomly. Random allocation sequence is generated in six trial centers by the editorial department of Chinese Journal of Evidence-Based Pediatrics, included infants are chosen and their information including name, gender, their parents' name and telephone is reported to the editorial department of Chinese Journal of Evidence-Based Pediatrics via WeChat. Then group division information is acquired, the tested commercially available formula and Friso formula are given out to infants accordingly.
4. Match of the breast milk group: Infants with purely breast milk-fed will be chosen. Infants'gender and body weight (±5%) of breast matched with milk-fed group commercially available formula subgroup and Friso formula subgroup.
5. Blinding method: Subjects, doctors and nurses know which formula is given. Personals in charge of assessing stool character and ery secretion, and data analysis, are blind to the information of group division.
6. Data records, monitoring and management 6.1 Data records 6.1.1 Original records: Subjects' follow-up care cards are original files in this clinical trial which is in duplicate copies. One copy should be saved in hospital. Original records shall be traceable. Each researcher must strictly follow the principle of GCP and ensure that he will record any observation and discovery in the follow-up care card and case report form (CRF), all data are consistent, no optional changes are allowed. If any correction is needed, the original record must not be changed, researchers can only add extra descriptions and explain the reason, the correction needs to be signed and dated by researchers who make it.

6.1.2 Case report form(CRF): Each in triplicate, it will be delivered to sponsors, main institutions of clinical research and participating institutions of clinical research. According to the principle of GCP, subjects' name should not appear in order to ensure their privacy. Subjects' name must be filled in the initials.

All of the choices"□" will be marked"×". If some inspection items are not examined or missed for some reason, it should be filled in: not examined. If the specific formula dosage is unknown, it should be filled in: unknown. When filled in the numbers, it should be filled in all □. If digits are not enough, it should be filled on right side. If left side is empty, it should be filled by 0. No null terms or missing items are allowed. Researchers must ensure that all data must be consistent with the original record.

If modifying, researchers should draw a horizontal line in the middle of the original record text, sidenote to modify, and then sign the modifier's name and the date. He must not smear or cover the original record.

6.1.3 Data Record of subjects' guardian: It should be recorded according to the items and their definitions in the designed CRF chart.