Dear editor
Endocrine and metabolic disorders play a crucial role in adverse pregnancy outcomes, which is currently a research hotspot. We noticed Lin et alCitation1 recently published a paper entitled “Association of Triglyceride-Glucose Index with Risk of Large for Gestational Age: A Prospective Cohort Study” in Diabetes Metabolic Syndrome and Obesity-Targets and Therapy. They delved into the relationship between the TyG index and the risk of large for gestational age (LGA) based on a birth cohort. They found that a higher TyG index in the first trimester was independently associated with a higher risk of LGA. Logically, a high TyG index in the first trimester may serve as an early predictor for LGA.
While we appreciate the novel work, certain aspects of the current study still need further improvement to align with clinical practice. First, there is a lack of the differential diagnosis of Hashimoto’s thyroiditis (HT), especially subclinical hypothyroidism. We note that the author excluded hypothyroidism and hyperthyroidism in Table 5 but did not exclude Hashimoto’s thyroiditis, which is particularly closely related to LGA in patients with TSH > 2.5 mIU/L. Maternal subclinical hypothyroidism in early pregnancy (TSH > 2.5 mIU/L) was closely associated with increased odds for LGA in male newborns (OR = 1.95, 95% CI = 1.22–3.11).Citation2 Additionally, a prospective cohort study with 175,112 women in China showed a J-shaped relationship between TSH and LGA (P < 0.001), in which TSH within 0.91 to 1.82 mIU/L was the potential safe range for preconception women.Citation3 Actually, over 30% of women with hypothyroidism (Hypo-HT) and euthyroidism-HT (Eu-HT) have TSH greater than 2.5 mIU/L in early pregnancy, 19.7% of women with Hypo-HT and 10.1% of women with Eu-HT have TSH higher than 4.0 mIU/L (P < 0.05).Citation4 To prevent/reduce the risk of thyroid insufficiency inducing adverse pregnancy outcomes such as LGA during early pregnancy, preconception thyroid function optimization for women with Hashimoto thyroiditis (HT) through levothyroxine sodium is strongly suggested by guidelines.Citation5 Second, there is a lack of evaluation data on serum ferritin levels. Serum ferritin concentration prior to pregnancy or in the first trimester can affect thyroid function, which is associated with adverse pregnancy outcomes, including LGA.Citation6
To sum up, only by improving the above deficiencies can the research results be more dependable.
Disclosure
The authors report no conflicts of interest in this communication.
References
- Lin L, Lin J, Yang F, et al. Association of triglyceride-glucose index with risk of large for gestational age: a prospective cohort study. Diabetes Metabol Syndr Obes. 2023;2023(16):3837–3846. doi:10.2147/DMSO.S436611
- Vrijkotte TGM, Hrudey EJ, Twickler MB. Early maternal thyroid function during gestation is associated with fetal growth, particularly in male newborns. J Clin Endocrinol Metab. 2017;102(3):1059–1066. doi:10.1210/jc.2016-3452
- Du H, Wu D, Zhou X, et al. Preconception TSH and adverse pregnancy outcomes in china: a nationwide prospective cohort study. J Clin Endocrinol Metab. 2022;107(7):e2770–e2776. doi:10.1210/clinem/dgac208
- Moleti M, Alibrandi A, Di Mauro M, et al. Preconception thyrotropin levels and thyroid function at early gestation in women with Hashimoto thyroiditis. J Clin Endocrinol Metab. 2023;108(7):e464–e473. doi:10.1210/clinem/dgac748
- Bekkering GE, Agoritsas T, Lytvyn L, et al. Thyroid hormones treatment for subclinical hypothyroidism: a clinical practice guideline. BMJ. 2019;365:l2006. doi:10.1136/bmj.l2006
- Li X, Zhang Z, Cai W, et al. Association between serum ferritin levels in early pregnancy and thyroid function and pregnancy outcomes in Chinese population. Int J Women’s Health. 2023;15:1951–1957. doi:10.2147/IJWH.S436651