Risk of preeclampsia and thyroid function in pregnant women with hypothyroidism / 中华围产医学杂志

ABSTRACT

Objective To investigate the relationship between gestational hypothyroidism and preeclampsia.Methods A retrospective study was conducted on 1 776 patients with gestational hypothyroidism,who gave birth in the International Peace Maternity & Child Health Hospital of China Welfare Institute,Shanghai Jiaotong University School of Medicine from January 2013 to December 2014.They were divided into three groups,including Improving Group (n=1 469),Progressing Group (n=133) and Remaining Group (n=174),based on their thyroid function at the first and third trimesters.Levels of thyroid hormones in the first and third trimesters were analyzed.Incidences of preeclampsia in those patients were calculated.And the correlation between thyroid function and incidence of preeclampsia was analyzed.T-test,Mann-Whitney U test,Chi-square test,variance analysis (SNK method) and Kruskal-Wallis H test or Logistic regression were performed for statistical analysis.Results (1) There were no statistical differences in age,gravidity and parity among the three groups.The pregestational body mass index in Progressing Group was lower than that in Improving group (21.1 ±2.9 vs 21.8±2.8,P＜0.05).(2) In the first trimester,the level of thyroid stimulating hormone (TSH) in Remaining Group was higher than those in Improving and Progressing Groups [(4.21 ± 1.69) vs (3.77±.3.03) and (2.00±0.57) mU/L,F=27.635,P＜0.01],and that in Improving Group was higher than that in Progressing Group (P＜0.05).The level of free thyroxine (FT4) in Progressing Group was higher than those in Improving and Remaining Groups [(16.18±9.67) vs (14.58± 1.71) and (14.54± 1.74) pmol/L,F=16.188,P＜0.01].In the third trimester,the TSH level in Remaining Group was higher than those in Improving and Progressing Groups [(5.07±0.86) vs (2.57±0.77) and (4.31 ±0.87) mU/L,F=28.986,P＜0.01],while the TSH level in Improving Group was higher than that in Progressing Group (P＜0.05).No statistical differences in FT4 levels (in the third trimester) and positive rates of thyroid peroxidase antibody (TPOAb) Were observed in the three groups.(3) Blood pressures (including diastolic and systolic blood pressures) in the first trimester and diastolic pressures in the third trimester showed no significant differences among the three groups.Systolic pressure of Improving Group in the third trimester was lower than that of Progressing Group [(119.4± 11.9) vs (121.8± 14.2) mmHg,P＜0.05,1 mmHg=0.133 kPa].(4) The incidence of preeclampsia in Progressing Group was higher than those in Improving and Remaining Groups [7.52％ (10/133) vs 1.29％ (19/1 469) and 3.45％ (6/174),x2=26.646,P＜0.01],and the incidence in Progressing Group was higher than those in Remaining and Improving Groups (both P＜0.05).The incidence of severe preeclampsia in Progressing Group was higher than that in Improving Group [6.02％ (8/133) vs 0.41％ (6/1 469),P＜0.05].There were no significant differences in incidences of mild preeclampsia among the three groups.(5) After adjusting for age,body mass index,gravidity and parity,the risk of severe preeclampsia in Improving Group was lower than that in Remaining Group (OR=0.233,95％CI:0.057-0.946,P＜0.05).Conclusions By improving thyroid function in pregnant women with hypothyroidism,the risk of preeclampsia,especially severe preeclampsia,could be reduced,which could improve maternal and neonatal outcomes.