Objective  To investigate the correlation between mild maternal anemia during the second (2nd) and third (3rd) trimester on behavioral development of the children aged 18 months, and to explore regulating effect of maternal intelligence quotient (IQ) on the correlation.

  Methods  The participants of the study were 2 826 pairs of mothers and infants who underwent antenatal examination in Ma'anshan Maternal and Child Health Hospital from May 2013 through September 2014. The relevance of maternal anemia during pregnancy to development delay among their children at the age of 18 months was analyzed with multivariate logistic regression analysis.

  Results  The detection rate of mild anemia during the 2nd and 3rd trimester were 27.1% and 26.0% among the mothers. After adjusting for confounding factors, mild maternal anemia during the 2nd trimester was a risk factors for the children's developmental delay in communication domain (relative risk RR = 2.65, 95% confidence interval 95% CI: 1.35 – 5.19) and mild anemia in the 3rd trimester was a risk factor for the children's developmental delay in individual-social domain (RR = 2.15, 95% CI: 1.24 – 3.73) compared to the children without maternal anemia. Also compared to those without maternal anemia and adjusting for confounding factors, the children with normal maternal IQ and mild maternal anemia only during the 2nd trimester and during both the 2nd and the 3rd trimester had an increased risk of developmental delay in communication domain, with the RR of 3.61 (95% CI: 1.50 – 8.72) and 2.60 (95% CI: 1.01 – 6.69); as for the children with normal maternal IQ and mild maternal anemia during the 3rd trimester, the risk of developmental delay in individual-social domain increased, with the RR of 2.04 (95% CI: 1.05 – 3.95); no significant correlation between mild maternal anemia and development delay of the children was observed among the children with low maternal IQ.

  Conclusion  Mild maternal anemia in the 2nd and 3rd trimester could impair communication domain and individual-social domain development in 18 months old children, and maternal IQ plays a regulatory role on the impairment.