Objective

The physiological adaptations during a normal pregnancy affect renal and thyroid function and levels of associated biochemical markers. An association between cystatin C (CysC), creatinine, and thyroid function has been considered in nonpregnant individuals but not in pregnant women specifically.

Methods

Cohort study within the North Denmark Region Pregnancy Cohort (2011–2015) with assessment of thyroid function and autoantibodies (ADVIA Centaur XPT, Siemens Healthineers) in serum residues from the early pregnancy. Consecutive samples (n = 1112) were selected for measurement of CysC and creatinine (Atellica CH 930, Siemens Healthineers), and results were linked to information in Danish nationwide registers for (i) establishment of pregnancy-specific reference intervals for CysC and creatinine and (ii) evaluation of the prevalence of maternal hypothyroidism in early pregnancy according to levels of CysC and creatinine.

Results

The established reference intervals (2.5–97.5 percentiles) differed by week of pregnancy (week 4–8, 9–11, 12–15) and were CysC: 0.58–0.92 mg/L; 0.54–0.91 mg/L; 0.52–0.86 mg/L; creatinine: 46.9–73.0 µmol/L; 42.0–68.4 µmol/L; 38.8–66.4 µmol/L. The prevalence of maternal autoimmune hypothyroidism in early pregnancy differed by the level of CysC and creatinine (<25th percentile; 25th–75th percentile; >75th percentile) and was for CysC 1.7%, 3.8%, 7.4% and for creatinine 2.5%, 4.1%, 7.1%.

Conclusions

Reference intervals for CysC and creatinine were dynamic in early pregnancy and decreased with increasing gestational age. Furthermore, higher levels of CysC and creatinine associated with a higher prevalence of maternal autoimmune hypothyroidism. Results encourage considerations on the underlying mechanisms for the association between markers of renal and thyroid function.

中文翻译：

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妊娠早期肾功能和母体甲状腺功能减退症的生化标志物

客观的

正常妊娠期间的生理适应会影响肾脏和甲状腺功能以及相关生化标志物的水平。半胱氨酸蛋白酶抑制剂 C (CysC)、肌酐和甲状腺功能之间的关联已在非妊娠个体中被考虑，但在孕妇中并未被考虑。

方法

丹麦北部地区妊娠队列（2011-2015）的队列研究，评估早期妊娠血清残留物中的甲状腺功能和自身抗体（ADVIA Centaur XPT，西门子 Healthineers）。 选择连续样本（n = 1112）来测量 CysC 和肌酐（Atellica CH 930，Siemens Healthineers），并将结果与​​丹麦全国登记册中的信息相关联，用于 (i) 建立 CysC 和肌酐的妊娠特定参考区间，以及(ii)根据CysC和肌酐水平评估妊娠早期母亲甲状腺功能减退症的患病率。

结果

建立的参考区间（2.5-97.5 百分位数）因怀孕周（第 4-8、9-11、12-15 周）而异，CysC：0.58-0.92 mg/L；CysC：0.58-0.92 mg/L；0.54–0.91 毫克/升；0.52–0.86 毫克/升；肌酐：46.9–73.0 µmol/L；42.0–68.4 微摩尔/升；38.8–66.4 微摩尔/升。妊娠早期母亲自身免疫性甲状腺功能减退症的患病率因 CysC 和肌酐水平而异（<25%；25-75%；>75%），CysC 为 1.7%、3.8%、7.4%，肌酐为 2.5%、4.1% %, 7.1%。

结论

CysC 和肌酐的参考区间在妊娠早期是动态的，并随着胎龄的增加而减小。此外，较高水平的 CysC 和肌酐与孕产妇自身免疫性甲状腺功能减退症的较高患病率相关。结果鼓励人们考虑肾功能和甲状腺功能标志物之间关联的潜在机制。