Min Li1, Shao Wei Wang1, Feng Li Wu1, Jin Shi2, Pu Lin Yu2, Xiu Ling Peng3, Liang Sun2. 1. Department of Gynecology and Obstetrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, China. 2. Institute of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, China. 3. Department of Gynecology and Obstetrics, Morin Dawa Daur Autonomous Banner Hospital, Hulunbuir 162850, Inner Mongolia Autonomous Region, China.
Abstract
OBJECTIVE: Abnormal maternal thyroid function is associated with preterm birth. However, this association stays dubious in relevant individual studies for ethnic difference reasons and lack of direct supporting data. This study aimed to evaluate the relationship between preterm birth and thyroid dysfunction or autoimmunity based on ethnic differences. METHODS: Relevant studies were identified through searches of MEDLINE, Excerpta Medica, Wan Fang, China Biological Medicine disc, and China National Knowledge Infrastructure from inception to June 15, 2016. Original articles in which an incidence or prevalence of thyroid dysfunction or autoimmunity before second trimester of pregnancy could be extracted were included. RESULTS: Thirty-two unique studies were included for the final meta-analysis. Patients involved were divided into two groups: Group 1 (G1) and Group 2 (G2) comprising of Asian and Caucasian populations, respectively. Positive thyroid antibodies were associated with the occurrence of preterm birth in both G1 [odds ratio (OR): 3.62, 95% confidence interval (CI): 2.83-4.65] and G2 (OR: 1.35, 95% CI: 1.17-1.56); hypothyroidism, only in G2 (OR: 1.20, CI: 1.09-1.33); and subclinical hypothyroidism or hypothyroxinemia, in neither group. CONCLUSION: Thyroid autoimmunity may be a more favorable factor leading to preterm birth among pregnant women of different ethnicities, compared with thyroid dysfunction.
OBJECTIVE: Abnormal maternal thyroid function is associated with preterm birth. However, this association stays dubious in relevant individual studies for ethnic difference reasons and lack of direct supporting data. This study aimed to evaluate the relationship between preterm birth and thyroid dysfunction or autoimmunity based on ethnic differences. METHODS: Relevant studies were identified through searches of MEDLINE, Excerpta Medica, Wan Fang, China Biological Medicine disc, and China National Knowledge Infrastructure from inception to June 15, 2016. Original articles in which an incidence or prevalence of thyroid dysfunction or autoimmunity before second trimester of pregnancy could be extracted were included. RESULTS: Thirty-two unique studies were included for the final meta-analysis. Patients involved were divided into two groups: Group 1 (G1) and Group 2 (G2) comprising of Asian and Caucasian populations, respectively. Positive thyroid antibodies were associated with the occurrence of preterm birth in both G1 [odds ratio (OR): 3.62, 95% confidence interval (CI): 2.83-4.65] and G2 (OR: 1.35, 95% CI: 1.17-1.56); hypothyroidism, only in G2 (OR: 1.20, CI: 1.09-1.33); and subclinical hypothyroidism or hypothyroxinemia, in neither group. CONCLUSION: Thyroid autoimmunity may be a more favorable factor leading to preterm birth among pregnant women of different ethnicities, compared with thyroid dysfunction.