Objective  To study the association between birth solar term and physical mal-development among children aged 6 ~ 36 months in Guangzhou, so as to provide evidence for children's health management and public health service policy making.

Methods  A retrospective survey method was used to recruit 13 802 children aged 6 ~ 36 months who received basic public health services in every community health service centers in a district of Guangzhou from June 2018 to December 2019 as research subjects. Growth and development status of the subjects were assessed based on the growth criteria for children aged 0 ~ 5 years issued by the World Health Organization in 2006. Circular distribution was used to test the distribution characteristics of solar terms with physical mal-development.

Result  The birth solar term started from beginning of spring within a natural year. The detection rates of children’s physical dysplasia decreased gradually, reaching the lowest in summer, and the lowest point at Grain in Ear (low birth weight was 1.68%, stunting was 1.01%, and wasting was 0.84%). From the birth of the solar term after Dew, the detection rates of physical dysplasia increased gradually, and the peak of low weight and stunting (5.82% and 4.74%, respectively) were between Frost and Light Snow, while the peak detection rate of wasting (3.84%) was between Light Snow and Minor Cold. The highest detection rates of physical dysplasia were among winter births (mean angle ɑ for low weight, stunting and wasting was 298.61°, 300.27° and 292.42°, respectively, P < 0.05), and the detection rates of low weight and stunting increased significantly. Compared with children born in winter, children born in summer were at lower risk of low weight (OR = 0.471, 95% CI: 0.365 ~ 0.609), stunting (OR = 0.631, 95% CI: 0.486 ~ 0.819) and wasting (OR = 0.471, 95% CI: 0.345 ~ 0.643); children born in autumn also had a relatively low risk of low weight (OR = 0.625, 95% CI: 0.49 6 ~ 0.787) and stunting (OR = 0.682, 95% CI: 0.531 ~ 0.878). And, there was no significant differences in the detection rates of low weight, stunting and wasting between children born in spring and winter (P > 0.05). At the age of 6 months, compared with children born in winter, children born in summer were at lower risk of low weight (OR = 0.440, 95% CI: 0.293 ~ 0.659), stunting (OR = 0.466, 95% CI: 0.306 ~ 0.709) and wasting (OR = 0.351, 95% CI: 0.190 ~ 0.648), and children born in autumn had a lower risk of stunting (OR = 0.693, 95% CI: 0.487 ~ 0.987). At the age of 18 months, children born in summer were at lower risk of low weight (OR = 0.464, 95% CI: 0.314 ~ 0.686), stunting (OR = 0.594, 95% CI: 0.402 ~ 0.877) and wasting (OR = 0.496, 95% CI: 0.307 ~ 0.802), and children born in autumn had a lower risk of low weight (OR = 0.554, 95% CI: 0.386 ~ 0.794) than children born in winter. At the age of 30 month, the differences of low weight, stunting and wasting detection rates between winter born children and the other seasons’ were not significant (P > 0.05).

Conclusion  The growth and development of children in Guangzhou is associated with birth solar terms, among which the children of 6 months and 18 months are greatly affected, while those of 30 months are not affected significantly, suggesting that the influence of birth solar terms on growth and development may be limited to early life.