Abstract： Objective To evaluate the clinical significance of thyroid stimulating hormone (TSH) and thyroid autoantibodies (anti-TGAb and anti-TPOAb) in cord blood of infants of mothers complicated with hypothyroidism and the influencing factors of neonatal thyroid function. Methods Clinical data of 67 singleton pregnant women complicated with hypothyroidism in Peking Union Medical College Hospital were analyzed retrospectively. Thyroid function and its autoantibody levels in maternal, cord blood and neonatal serum at 5-7 d after birth were compared. Umbilical TSH level and its affecting factors were also investigated. The results of TSH was expressed as median (25th-75th percentile). Results (1) Umbilical TSH levels were elevated in 9. 0% (6/67) of all infants born to mothers complicated with hypothyroidism. (2) No correlation was found in TSH levels between cord blood and venous blood in neonates 5-7 d after birth. Umbilical TSH levels were significantly higher in infants born vaginally than in those born abdominally [10. 20(6. 10-12. 80) mU/L vs 5. 86(4.02-7.74) mU/L,P=0.001]. Higher umbilical TSH levels were also detected in those complicated with fetal distress and preterm birth compared with those withoutere [fetal distress: (10. 36(6. 61-13. 37) mU/L and 6. 89(4. 18-9. 70) mU/L, P = 0. 046; preterm birth: 8. 90(7. 60-10. 33) mU/L and 6.84(4.17-9. 80) mU/L,P=0. 046,0. 049)]. (3) The anti-TGAb levels in cord blood were positively correlated with that in neonatal serum at 5-7 d after birth (r=0. 960, P = 0. 000), and the same was true for anti-TGPOAb levels (r= 0. 975, P = 0. 000). Maternal thyroid autoantibody levels (anti-TGAb and anti-TPOAb) had significant effect on umbilical antibody levels (P = 0. 003 and 0. 000, respectively), but not on the neonatal TSH levels (P>0. 05). Conclusions Umbilical TSH levels are affected by many delivery factors which may limit its prediction role on congenital hypothyroidism. However, there is an increased risk of elevated umbilical TSH, anti-TGAb and anti-TPOAb levels among these patients which may increase the risk of congenital hypothyroidism. Further follow up of these infants is warranted.