Association between maternal zinc status and the physical development of infants aged 0–12 months: a cohort study in Northeast China

Background Zinc serves as an indispensable element for fetal growth and neonatal development. Presently, the evidence of the relationship between zinc during pregnancy and the physical development (length and weight) of offspring remains inconsistent. The aim of this study was to explore the relationship between them. Methods This study recruited pregnant women who gave birth from January 2019 to August 2024. Zinc of these pregnant women in the third trimester pregnancy was tested by atomic absorption spectrometer. Telephone follow-up was carried out when babies were 6 and 12 months old using a structured questionnaire. Multiple linear regressions were used to explore the relationship between maternal zinc status and physical development of infants. Results We included a total of 291 mother-child pairs and followed up 249 pairs at 6 months and 216 pairs at 12 months. The maternal zinc deficiency rate was 29.6%. Infants of zinc-sufficient mothers had higher birth weight-for-age z -score (β = 0.112; 95% CI : 0.004, 0.374) and 6-month weight-for-age z -score (β = 0.174; 95% CI : 0.113, 0.640) and longer 6-month length-for-age z -score (β = 0.165; 95% CI : 0.104, 0.699) compared to those of zinc-deficient mothers. In addition, the level of zinc in pregnant women was associated with the weight growth rate (β = 0.120 kg/month; 95% CI : 0.001, 0.085) and length growth rate (β = 0.134 cm/month; 95% CI : 0.010, 0.221) from 0 to 6 months, but not with the weight-for-length z -score at 6 months. Conclusions Maternal zinc status is associated with the birth weight and the physical development at 6 months of infants, but adequate zinc does not increase the risk of obesity at 6 months and is not associated with physical development at 12 months.