Method Selection Of Iodine Supplementation And Treatment In Pregnant Women With Hypothyroxinemia In The Second Half Of Pregnancy

Objective:This study was designed to observe iodine nutrition and thyroid function in pregnant women in the second half of pregnancy,and to investigate the effect of iodine supplementation on thyroid function and urinary iodine concentration.We also explored if it was necessary for intervention of isolated hypothyroxinemia(IH)in pregnancy.Methods:A total of 1269 pregnant women aged 24-27+6 weeks were included in the study.Age,gestational age,blood pressure were measured,thyroid stimulating hormone(TSH),free thyroxine(FT4),free triiodothyroxine(FT3)and urinary iodine concentration(UIC)were measured before treatment and 4 weeks and 8 weeks after treatment,Urinary iodine/Urine creatinine(UI/UCr)was tested in some patients.The iodine deficiency people during pregnancy was randomly divided into the combined iodine supplement group(group A)and the simple food supplement group(group B).The urine iodine concentration before and after treatment was compared between the two groups.The patients with isolated hypothyroxinemia were divided into G1 group(Supplement of levothyroxine+iodine),G2 group(Supplement of Iodine),G3 group(Supplement of levothyroxine),G4 group(control group).The changes of thyroid function was observed after 4 weeks and 8 weeks of treatment in the four groups.All the results were analyzed using SPSS 22.0 for statistical analysis.Results:1.The iodine-deficient during pregnancy population accounted for 50.04%of all included subjects,and accounted for 49.2%,50.98%,46.32%,and 53.62%of the normal thyroid function,overt hypothyroidism,subclinical hypothyroidism,and hypothyroxinemia(HT)respectively.There was no significant difference in the number of iodine deficiency between different thyroid function groups by chi-square test(P>0.05).There was no significant difference in thyroid function between different iodine nutrition groups(P>0.05).2.There was no significant difference in the UIC between the iodine-deficient group A and group B before treatment(P>0.05).After 4 weeks and 8 weeks of treatment,the UIC of the two groups were significantly higher than those before treatment(P<0.01).After 4 weeks of treatment,there was no significant difference in UIC between the two groups(P>0.05).After 8 weeks of treatment,the UIC of group A were significantly higher than those of group B(P<0.05).3.By comparison the IH subjects,after 4 weeks of treatment,the levels of FT3 and FT4 in G1 group were higher than those before treatment and the level of TSH was decreased(P<0.01).Pregnant women in the G3 group had lower TSH and higher FT4 levels than those before treatment(P<0.01),there was no statistical difference in the level of FT3(P>0.05).There were no significant differences in the levels of TSH,FT3 and FT4 between the G2 and G4 groups after 4 weeks of treatment(P>0.05).After 8 weeks of treatment,the levels of TSH in G4 group increased and the levels of FT4 and FT3 decreased than those before(P<0.05).The levels of TSH,FT3 and FT4 in G1,G2 and G3 groups were not significantly different from those after 4 weeks treatment(P>0.05).4.The main effect of levothyroxine can reduce TSH and increase FT4(P<0.01),but there is no significant difference in the effect of FT3(P>0.05).The main effect of iodine supplementation did not improve TSH,FT4 and FT3(P>0.05).The interaction between levothyroxine and iodine supplementation did not improve the levels of TSH and FT4(P>0.05)significantly,but increased FT3(P=0.01).Conclusion:1.Iodine deficiency is prevalent in pregnant women in the second half of pregnancy.2.In terms of iodine supplementation,Iodine-containing pregnant women ’ s multivitamin combined with food supplementation of iodine is preferred.3.Iodine supplementation can delay or prevent further imbalance of thyroid hormone levels in pregnant women with IH in the second half of pregnancy.On the basis of this,combined with levothyroxine can further improve the thyroid function of pregnant women with IH iodine deficiency in the middle-late of pregnancy.4.Iodine combined with levothyroxine treatment is more advantageous than simply supplementing levothyroxine in improving FT3 levels.