Is subclinical hypothyroidism a risk factor for gestational diabetes mellitus?
Is subclinical hypothyroidism a risk factor for gestational diabetes mellitus?
Objective: Gestational diabetes mellitus is characterized by increased blood sugar that first appears during pregnancy. Multiple articles
have described a relationship between hypothyroidism/subclinical hypothyroidism (SCH) and a rise in the risk of concomitant
pregnancy complications, including gestational diabetes mellitus (GDM), but the effect of SCH on pregnancy is uncertain in the
literature. We clarified the contribution of SCH to GDM development.
Patients and Methods: We conducted a retrospective study. From the patient records, the first 250 pregnant women who applied to our
hospital for screening at 20-24 weeks and had glucose tolerance tests were included in our study. Retrospectively, all these pregnant
women’s first-trimester thyroid-stimulating hormone (TSH) levels were recorded. We created two groups according to the oral glucose
tolerance test (OGTT) results: a case group diagnosed with GDM and a control group with average blood glucose. Their first-trimester
TSH levels were compared between the two groups and defined whether they had euthyroid, subclinical hypothyroidism (TSH=2.5-
5.5mIU/L) or overt hypothyroidism (TSH >5.5).
Results: We diagnosed 37 of 191 patients (19.4%) with GDM. When we checked the case and control groups, the mean TSH of the
GDM group was 1.8 mIU/L, and the control group was 1.7 mIU/L, but the difference was not statistically significant (p=0.121). 24.32%
(n=9) of 37 pregnant women with GDM were diagnosed with subclinical hypothyroidism/hypothyroidism; this rate was as low as
14.93% (n=28) in the non-GDM group, but no statistical difference was found (p=0.21).
Conclusion: It can be predicted that other accompanying factors may be the primary determinant in the development of GDM rather
than subclinical hypothyroidism. Risk scales that include the first trimester TSH level should be established for the development of
GDM.
___
- [1] Mack LR, Tomich PG. Gestational Diabetes: Diagnosis,
Classification, and Clinical Care. Obstet Gynecol Clin North
Am 2017;44:207-17. doi: 10.1016/j.ogc.2017.02.002
- [2] Alfadhli EM. Gestational diabetes mellitus. Saudi Med J
2015;36:399-406. doi: 10.15537/smj.2015.4.10307
- [3] Zhang C, Rawal S, Chong YS. Risk factors for gestational
diabetes: is prevention possible? Diabetologia 2016;59:1385-
90. doi: 10.1007/s00125.016.3979-3
- [4] Giannakou K, Evangelou E, Yiallouros P, et al. Risk factors
for gestational diabetes: An umbrella review of meta-analyses
of observational studies. PLoS One 2019 ;14:e0215372. doi:
10.1371/journal.pone.0215372
- [5] Maraka S, Ospina NM, O’Keeffe DT, et al. Subclinical
hypothyroidism in pregnancy: a systematic review and metaanalysis.
Thyroid 2016;26:580-90. doi: 10.1089/thy.2015.0418
- [6] Tudela CM, Casey BM, McIntire DD, Cunningham FG.
Relationship of subclinical thyroid disease to the incidence
of gestational diabetes. Obstet Gynecol 2012 ;119:983-8. doi:
10.1097/AOG.0b013e318250aeeb.
- [7] Chen LM, Du WJ, Dai J, et al. Effects of subclinical
hypothyroidism on maternal and perinatal outcomes
during pregnancy: a single-center cohort study of a Chinese
population. PloS One 2014;9:e109364. doi:10.1371/journal.
pone.0109364
- [8] Nelson DB, Casey BM, McIntire DD, Cunningham FG.
Subsequent pregnancy outcomes in women previously
diagnosed with subclinical hypothyroidism. Am J Perinatol.
2014;31:77-84. doi: 10.1055/s-0033.133.4457.
- [9] [Guideline] American Diabetes Association. 2. Classification
and Diagnosis of Diabetes: Standards of Medical Care in
Diabetes-2020. Diabetes Care 2020;43 (Suppl 1): S14-S31.
- [10] Cleary-Goldman J, Malone FD, Lambert-Messerlian G,
et al. Maternal thyroid hypofunction, and pregnancy
outcome. Obstet. Gynecol 2008;112:85-92. doi:10.1097/
AOG.0b013e3181788dd7
- [11] Stagnaro-Green A, Abalovich M, Alexander E, et al. American
Thyroid Association Taskforce on Thyroid Disease During
Pregnancy and Postpartum. Guidelines of the American
Thyroid Association for diagnosing and managing thyroid
disease during pregnancy and postpartum. Thyroid
2011;21:1081-125. doi: 10.1089/thy.2011.0087
- [12] Alexander EK, Pearce EN, Brent GA, et al. 2017 Guidelines
of the American Thyroid Association for the Diagnosis and
Management of Thyroid Disease During Pregnancy and
the Postpartum. Thyroid 2017;27:315-89. doi: 10.1089/
thy.2016.0457
- [13] Veltri F, Belhomme J, Kleynen P, et al. Maternal thyroid
parameters in pregnant women with different ethnic
backgrounds: Do ethnicity-specific reference ranges
improve the diagnosis of subclinical hypothyroidism?
Clin Endocrinol (Oxf) 2017 ;86:830-6. doi: 10.1111/
cen.13340
- [14] Bestwick JP, John R, Maina A, et al. Thyroid stimulating
hormone and free thyroxine in pregnancy: expressing
concentrations as multiples of the median (MoMs). Clin Chim
Acta 2014;430:33-7. doi: 10.1016/j.cca.2013.12.030
- [15] Cotzias C, Wong SJ, Taylor E, Seed P, Girling J. A. A study
to establish gestation-specific reference intervals for
thyroid function tests in normal singleton pregnancy. Eur
J Obstet Gynecol Reprod Biol 2008;137:61-6. doi: 10.1016/j.
ejogrb.2007.10.007
- [16] Springer D, Bartos V, Zima T. Reference intervals for thyroid
markers in early pregnancy determined by 7 different
analytical systems. Scand J Clin Lab Invest 2014;74:95-101.
doi: 10.3109/00365.513.2013.860617
- [17] Lambadiari V, Mitrou P, Maratou E, et al. Thyroid hormones
are positively associated with insulin resistance early in the
development of type 2 diabetes. Endocrine 2011;39:28-32.
https://doi: 10.1007/s12020.010.9408-3
- [18] Toulis KA, Stagnaro-Green A, Negro R. Maternal subclinical
hypothyroidism and gestational diabetes mellitus: a metaanalysis.
Endocr Pract 2014;20:703-14. doi: 10.4158/EP13440.
RA
- [19] Agarwal MM, Dhatt GS, Punnose J, Bishawi B, Zayed R.
Thyroid function abnormalities and antithyroid antibody
prevalence in pregnant women at high risk for gestational
diabetes mellitus. Gynecol Endocrinol 2006;22:261-6. doi:
10.1080/095.135.90600630470
- [20] Shahbazian H, Shahbazian N, Rahimi Baniani M, Yazdanpanah
L, Latifi SM. Evaluation of thyroid dysfunction in pregnant
women with gestational and pre-gestational diabetes. Pak J
Med Sci 2013;29:638-41. doi: 10.12669/pjms.292.2862
- [21] Ying H, Tang YP, Bao YR, et al. Maternal TSH level and
TPOAb status in early pregnancy and their relationship to the
risk of gestational diabetes mellitus. Endocrine 2016 ;54:742-
50. doi: 10.1007/s12020.016.1022-6
- [22] Gong LL, Liu H, Liu LH. Relationship between hypothyroidism
and the incidence of gestational diabetes: A meta-analysis.
Taiwan J Obstet Gynecol 2016 ;55:171-5. doi: 10.1016/j.
tjog.2016.02.004
- [23] Yang S, Shi FT, Leung PC, Huang HF, Fan J. Low thyroid
hormone in early pregnancy is associated with an increased
risk of gestational diabetes mellitus. J Clin Endocrinol Metab
2016;101:4237-43. doi: 10.1210/jc.2016-1506
- [24] Lee SY, Pearce EN. Assessment and treatment of thyroid
disorders in pregnancy and the postpartum period. Nat Rev
Endocrinol 2022;18:158-71. doi: 10.1038/s41574.021.00604-z.
- [25] Gietka-Czernel M, Glinicki P. Subclinical hypothyroidism
in pregnancy: controversies on diagnosis and treatment. Pol
Arch Intern Med 2021; 131: 266-75. doi:10.20452/pamw.4482