中文摘要：

目的比较4、6月龄母乳喂养婴儿各铁状况指标的性别差异。方法在北京某医院征集铁营养状况正常、足月妊娠的孕妇，选择正常出生体重的足月婴儿并要求婴儿在4月龄内基本纯母乳喂养。在4月龄时将追踪到的婴儿随机分成对照组和补铁组，补铁组婴儿进行为期2个月的预防性铁补充（补铁剂量为每日1mg／kg），对照组婴儿不予干预。4月和6月龄时，采集静脉血测定血常规及其他各项铁营养状况指标并测量其生长发育各项指标。结果追踪结束后，4、6月龄时完成随访的婴儿分别有178例、85例。4月龄时男婴的Hb水平比女婴低1g／L，但无统计学差异（P=0．422）。男婴的MCV值、SF值均低于女婴，sT侬值高于女婴，三个指标的性别问差异具有统计学意义。6月龄时各指标结果保持了4月时的差异趋势，MCV的性别差异具有统计学意义。结论4月龄和6月龄男婴患铁缺乏的风险更大，需要针对不同性别制定各铁营养状况指标的诊断界值和膳食铁需要量，同时注意科学喂养。

英文摘要：

Objective To study gender differences in different measures of iron status in infants aged 4 and 6 months old. Methods Term delivery pregnant women with normal iron status were recruit with informed consent. Infants with normal birth weight were selected and exclusive breastfeeding were required. All infants were randomly assigned into one control group and one iron supplement group at 4 months old. The latter group were given a daily dose of iron supplement corresponding to l mg/kg body weight of elemental iron from 4 to 6 month. At 4 and 6 months old, vein blood were sampled to analyze hemoglobin （Hb）, mean cell volume （MCV）, serum ferritin（SF）, and soluble transferrin receptors （sTiR） and the growth indices were measured. Results Data of infants at 4 months old （ n = 178） and 6 months old （ n = 85 ） were collected. At 4 months old, male infants had significantly lower MCV and SF and higher sTfR, male infants had lower Hb but with no significant difference. 6 months old, the trends of differences stayed the same as at 4 months old, and MCV remained significant. Conclusion Male infantsmay have a higher risk to develop iron deficiency. Male infants may have a higher risk to develop iron deficiency. There needs to be respective diagnostical cut-off values and dietary iron requirement for male and female infants. At the same time, correct feeding is necessary