Placental Iodine and Thyroxine Transport – Relationship with Pregnancy Complications and Perinatal Outcome

• Other Authors: Ng, Yu Tai Russell (author.)
• Format: Others
• Language: English; Chinese
• Published: 2016
• Online Access: http://repository.lib.cuhk.edu.hk/en/item/cuhk-1292219

此論文包括多個前瞻性橫斷面研究探討甲狀腺臨床功能正常之香港本地孕婦患上碘缺乏病的發生率，及孕婦碘攝取量，母體甲狀腺功能，胎兒甲狀腺功能，胎盤之轉甲狀腺素蛋白及鈉碘轉運體之表達水平在缺碘孕婦及碘充足孕婦之間的分別。研究包括患孕期併發症之孕婦，如妊娠糖尿病，子癎前期，單絨毛膜雙羊膜雙胞胎。 === 甲狀腺功能正常及正常或有併發症之孕婦獲邀參與本研究尿液碘含量是用作斷定孕婦的碘營養狀況。每日碘攝取量以一份飲食頻率問卷作估計。臍帶血及胎盤樣本用作檢驗胎兒甲狀腺功能和胎盤之轉甲狀腺素蛋白及鈉碘轉運體之表達水平。研究更包括懷有併發症之孕婦會跟正常孕婦之比較。 === 以世界衛生組織訂立之尿液碘含量準則，75.2%孕婦患碘缺乏。她們有較高的甲狀腺球蛋白、較高機率有甲狀腺球蛋白>13ug/L及較低的甲狀腺素，此結果均反映碘缺乏症的存在。孕婦和胎兒的甲狀腺功能關係在碘缺乏和碘足夠的情況下有不同的模式，但胎盤轉甲狀腺素蛋白及鈉碘轉運體之表達水平無分別。 === 有妊娠糖尿病之孕婦誕下較重之嬰兒，但母體及胎兒甲狀腺功能，胎盤轉甲狀腺素蛋白及鈉碘轉運體之表達水平沒有分別。但孕婦和胎兒的甲狀腺功能關係有所不同。 === 患有子癎前期之孕婦有較短的妊娠期、較低的胎盤鈉碘轉運體之表達水平、較輕的嬰兒體重、較輕的胎盤重量、嬰兒有較少的甲狀腺素及血清轉甲狀腺素蛋白水平。兩組孕婦亦擁有不同模式的孕婦和胎兒的甲狀腺功能，及胎盤鈉碘轉運體之表達水平關係。 === 懷有雙胞胎的孕婦有較高的每日碘攝取量及產前補充劑之使用次數，和較低的血清轉甲狀腺素蛋白水平。雙胞胎之間的胎兒甲狀腺功能沒有分別，但較輕的雙胞胎有較輕的體重，和較高的臍帶靜脈二氧化碳分壓水平。跟單胞胎相比，雙胞胎有較輕的出生體重及較少的血清轉甲狀腺素蛋白水平，但有較高的胎盤鈉碘轉運體之表達水平。兩組雙胞胎擁有不同模式的胎兒的甲狀腺功能，及胎盤鈉碘轉運體之表達水平關係。 === 不同模式的關係及胎盤鈉碘轉運體之表達水平反映出胎盤適應過程，這意味著成功的胎盤適應以維持胎兒正常的甲狀腺功能，從而保持胎兒正常發育及成熟過程中擔任著重要的角色，而最後令有孕期併發症之孕婦跟正常孕婦有近似的懷孕結果。 === This thesis consists of a number of prospective cross-sectional studies to examine the incidence of iodine deficiency in local euthyroid gravidae, and its relationship with maternal iodine intake, and maternal and fetal thyroid function in iodine deficient and sufficient gravidae. In addition, the study also examined placental transthyretin (TTR) and sodium-iodide symporter (NIS) expression in normal and complicated pregnancies, including gestational diabetes mellitus (GDM), pre-eclampsia (PET) and monochorionic diamniotic (MCDA) twins. === Clinically euthyroid gravidae carrying normal or complicated pregnancies were recruited for the assessment of maternal thyroid function and iodine status as reflected in urinary iodine excretion. A food frequency questionnaire was used to estimate iodine intake. Umbilical cord blood and placenta were collected at delivery to determine fetal thyroid function and placental TTR and NIS expression. For gravidae with complicated pregnancies, matched controls were identified and recruited for comparison. === According to the World Health Organization urinary iodine concentration criterion, 75.2% gravidae were identified as iodine deficient. Presence of iodine deficiency was supported by the significantly higher maternal thyroglobulin level and incidence of maternal thyroglobulin>13ug/L, together with lower fetal free thyroxine (fT4) level, in the deficient group. Different patterns of correlation in maternal and fetal thyroid function were found between iodine deficient and sufficient gravidae, but no difference in placental TTR and NIS expression was found. === Gravidae with GDM delivered infants with significantly higher birth weight, but no difference in maternal and fetal thyroid function, or placental expression of TTR and NIS was found between the GDM and control groups. Nevertheless, there were different patterns of correlation in maternal and fetal thyroid function between GDM and control gravidae. === Compared with the normal group, the PET group had significantly shorter gestation, lower placental NIS protein expression, birth weight, placental weight, and fetal fT4 and serum TTR levels. Different patterns of correlation in maternal and fetal thyroid function, and placental NIS expression, were found between PET and control gravidae. === Compared with gravidae carrying singleton pregnancies, gravidae carrying twins had significantly higher daily iodine intake and frequency of supplement use, but lower serum TTR level. No difference in fetal thyroid function was found between the heavi === Ng, Yu Tai Russell. === Thesis Ph.D. Chinese University of Hong Kong 2016. === Includes bibliographical references (leaves ). === Abstracts also in Chinese. === Title from PDF title page (viewed on …). === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only. === Detailed summary in vernacular field only.