[The trend of birth weight of full-term newborns and its association with parental reproductive age in Chongqing municipality from 2010 to 2022].

To analyze the trend of abnormal birth weight of full-term newborns and its correlation with parental reproductive age in Chongqing municipality from 2010 to 2022. Based on the Chongqing Birth Certificate System, full-term newborns born from January 2010 to December 2022 were selected. Parental information and birth weight were abstracted from the system. The joinpoint regression model was used to assess the trend of incidence of low birth weight (LBW) and macrosomia in the offspring from 2010 to 2022. The logistic regression model was utilized to analyze the association between parental reproduction age and birth weight of newborns. The average birth weight of 3 155 542 newborns was (3 305.8±410.5) g. The joinpoint regression model showed a decreasing trend for the incidence of LBW from 2010 to 2016 (APC=-4.26%, P<0.05), and an increasing trend from 2020 to 2022 (APC=8.99%, P<0.05). The incidence of macrosomia exhibited a decreasing trend from 2015 to 2022 (APC=-3.37%, P<0.05). The logistic regression model showed that, compared to the group with parents aged 20-34 years, the risk of LBW increased in other age groups. The risk of macrosomia decreased when either parent was aged<20 years, and increased when both parents were aged≥20 years. In conclusion, from 2010 to 2022, the incidence of LBW in full-term offspring in Chongqing municipality decreased first and then increased, and the incidence of macrosomia increased first and then decreased. Both young and advanced parental age were associated with an increased risk of LBW in offspring, and advanced parental age was also associated with an increased risk of macrosomia in offspring. Attention should be paid to the effects of advanced maternal and paternal age on offspring birth weight. Further efforts to control childbearing at a young age were needed.