Objective  To examine blood pressure among pregnant women with different iodine nutritional status in early pregnancy．

  Methods  We recruited 800 pregnant women in early pregnancy with convenient sampling at a grass-roots hospital in Nanjing city from January 2016 to January 2018 and 400 healthy non-pregnant female physical examinees were recruited as the controls at the same hospital during the same period. Urine iodine and blood pressure of the participants were measured and analyzed.

  Results  Iodine sufficiency (urine iodine median = 150 – 499 μg/L), iodine deficiency (<150 μg/L) and iodine excess (≥ 500 μg/L) were observed among 529, 187, and 84 pregnant women. The prevalence rate of hypertension was significantly higher among the pregnant women than among the controls (P<0.01) and the prevalence rate of hypertension was significantly higher among the participants with iodine deficiency than among those with iodine sufficiency (χ² = 6.78, P = 0.009).

  Conclusion  Imbalanced iodine nutrition may increase gestational hypertension risk among pregnant women in early pregnancy.