The purpose of this study was to investigate the nutrients in breast milk of Chinese mothers and its related factors, as well as exploring the early development of infants.

Breast milk contains a variety of nutrients that are beneficial to the early development of infants, such as lipids, Vitamins and so on. At present, the level of these nutrients in milk and infant formula are lower and which are present in a different form from that in breast milk. Therefore, this study was designed to investigate the level of nutrients in breast milk of Chinese mothers and learn about its related factors, as well as exploring the relationships between these nutrients and the early development of infants.

Inclusion Criteria:

• age 20-45 years
• natural delivery, singleton pregnancy
• healthy term infants（at 37-42 weeks of pregnancy）
• don't smoke and drink
• self-evaluation as physical health
• breastfeeding at least until three months of age
• Apgar score > 8
• sign informed consent

Exclusion Criteria:

• suffering from mastitis
• gestational diabetes, hypertension and other metabolic diseases
• AIDS, tuberculosis and other acute or chronic infectious diseases
• severe heart and kidney diseases
• mental system diseases
• cancer and other malignant consumptive disease
• take drugs that affect nutrient metabolism
• infants with congenital and genetic diseases
• with lactation contraindications
• don't agree to sign informed consent

Pregnant women and breast-feeding mothers of this study were recruited from Clifford Hospital during the perinatal period or lactation period