Department of Obstetrics and Gynaecology, Faculty of Health Sciences, Walter Sisulu University, Private Bag x1 WSU, Mthatha, 5117, South Africa.
Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.
BMC Pregnancy Childbirth. 2022 Feb 4;22(1):98. doi: 10.1186/s12884-021-04356-6.
Preeclampsia is a leading cause of maternal mortality and morbidity in South Africa. Iodine deficiency in pregnancy, which is amenable to correction through iodine supplementation, has been reported to increase the risk of preeclampsia. However, the association of iodine nutrition status with preeclampsia in South Africa has not been studied.
We enrolled 51 randomly selected normotensive pregnant controls at term together with 51 consecutively selected cases of preeclampsia and 51 cases of severe preeclampsia/eclampsia, all in the third trimester, from Mthatha Regional and Nelson Mandela Academic Hospital in the Eastern Cape Province. Urinary iodine concentration (UIC), serum thyroid-stimulating hormone (TSH), triiodothyronine (FT3), thyroxine (FT4) and thyroglobulin (Tg) levels were compared between cases and controls.
The respective chronological and gestational ages at enrolment for normotensive, preeclampsia and severe preeclampsia/eclampsia participants were: age 23, 24 and 19 years (p = 0.001), and gestational age 38, 34, and 35 weeks (p < 0.001). The median gravidity was 1 for all three groups. The median UIC, FT4, FT3 revealed a decreasing and Tg a rising trend with the severity of preeclampsia (p < 0.05). TSH had a non-significant rising trend (p > 0.05). The respective median values for normotensive, preeclampsia and severe preeclampsia/eclampsia participants were UIC 217.1, 127.7, and 98.8 μg/L; FT4 14.2, 13.7, and 12. pmol/L; FT3 4.8, 4.4, and 4.0 pmol//L; Tg 19.4, 21.4, and 32. Nine microgram per liter; TSH 2.3, 2.3, and 2.5 mIU/L. UIC < 100 μg/L, Tg > 16 μg/L and FT4 < 11.3 pmol/L were independent predictors of preeclampsia/eclampsia syndrome.
Women with severe preeclampsia/eclampsia had significantly low UIC and high Tg, suggesting protracted inadequate iodine intake. Inadequate iodine intake during pregnancy severe enough to cause elevated Tg and FT4 deficiency was associated with an increased risk of severe preeclampsia/eclampsia.
子痫前期是南非孕产妇死亡和发病的主要原因。在妊娠期间，碘缺乏可通过碘补充来纠正，据报道，它会增加子痫前期的风险。然而，南非碘营养状况与子痫前期之间的关联尚未得到研究。
我们在东开普省姆塔塔地区和纳尔逊·曼德拉学术医院招募了 51 名随机选择的正常妊娠对照组，以及 51 名连续选择的子痫前期病例和 51 名重度子痫前期/子痫病例，所有病例均来自妊娠晚期。比较病例组和对照组的尿碘浓度（UIC）、血清促甲状腺激素（TSH）、三碘甲状腺原氨酸（FT3）、甲状腺素（FT4）和甲状腺球蛋白（Tg）水平。
正常妊娠、子痫前期和重度子痫前期/子痫患者的登记时年龄和孕周分别为：年龄 23、24 和 19 岁（p=0.001）和孕周 38、34 和 35 周（p<0.001）。三组的中位孕次均为 1。随着子痫前期的严重程度，UIC、FT4、FT3 的中位数呈下降趋势，Tg 的中位数呈上升趋势（p<0.05）。TSH 呈非显著上升趋势（p>0.05）。正常妊娠、子痫前期和重度子痫前期/子痫患者的中位数 UIC 值分别为 217.1、127.7 和 98.8μg/L；FT4 分别为 14.2、13.7 和 12.0pmol/L；FT3 分别为 4.8、4.4 和 4.0pmol/L；Tg 分别为 19.4、21.4 和 32.9ng/ml；TSH 分别为 2.3、2.3 和 2.5mIU/L。UIC<100μg/L、Tg>16μg/L 和 FT4<11.3pmol/L 是子痫前期/子痫综合征的独立预测因子。
重度子痫前期/子痫患者 UIC 明显降低，Tg 明显升高，提示碘摄入不足持续时间较长。妊娠期碘摄入不足严重到足以导致 Tg 升高和 FT4 缺乏，与重度子痫前期/子痫的风险增加有关。
