Int J Health Life Sci. 2018 July; 4(2):e85525. Published online 2018 November 6. doi: 10.5812/ijhls.85525. Letter Does HbA 1 c Have a Potential in Gestational Diabetes Mellitus Diagnosis? Shima Moradi 1 and Hadi Abdollahzad 1, * 1 Department of Nutritional Sciences, Research Center for Environmental Determinants of Health (RCEDH), Kermanshah University of Medical Sciences, Kermanshah, Iran * Corresponding author: Department of Nutritional Sciences, Research Center for Environmental Determinants of Health (RCEDH), Kermanshah University of Medical Sciences, Kermanshah, Iran. Email: hadi_nut@yahoo.com Received 2018 October 19; Revised 2018 November 04; Accepted 2018 November 04. Keywords: HbA1 c, Diabetes Mellitus, Diagnosis Dear Editor, Gestational diabetes mellitus (GDM) is considered to presence of hyperglycemia for the first time during preg- nancy which can affect up to 5% of pregnancies (1). Preg- nant women with GDM are likely to develop type 2 di- abetes 6 - 7 times more than healthy pregnant women (2). Also, GDM causes complications such as macrocosmic neonate, preeclampsia, the need for cesarean section deliv- ery, shoulder dystocia and even the death of neonate (3). Risk factors that contribute to GDM include maternal overweight, obesity, age older than 35 years, family his- tory of diabetes, macrocosmic neonate, history of GDM in previous pregnancies, and non-Caucasian ethnicity (1, 3). Based on WHO criteria, GDM is usually diagnosed at 24 to 28 weeks of pregnancy (4). Early diagnosis of GDM is im- portant not only in the treatment of GDM and prevention of postpartum type 2 diabetes, but also can lead to decrease other mentioned complications (2). Therefore, it is nec- essary to provide precise index for the diagnosis of GDM, which impose the less onerous on the pregnant mother (5). Many studies have confirmed that the glycated hemoglobin (HbA1c) value is an accurate index for di- agnosis of diabetes that does not require fasting (2, 5, 6). Measurement of HbA 1 c is easy and only needs to be mea- sured once (7). Wu et al. (8) reported that HbA 1 c combined with Hematocrit are useful criteria for early diagnosis of GDM. Inconsistent with this finding another study was shown that measurement of HbA 1 c in first-trimester did not have sensitivity and specificity to diagnose GDM (9). The results of a meta-analysis were showed that HbA 1 c is not a sensitive index for GDM diagnosis even in women with prior GDM (10). Many studies have shown that HbA 1 c cannot be an appropriate alternative to other GDM di- agnostic tests and has provided contradictory results (1, 11, 12). In fact HbA 1 c is the mean of plasma glucose value in around the last 3 - 4 months and believed to be not a good indicator of GDM diagnosis due to the high amount of time required for changing HbA 1 c and high turnover in red blood cells during pregnancy (11). A result from a cohort study was showed that since glycation of Hb requires several month, this index is not recommended for GDM diagnosis (13). On the other hand, some studies were reported that ethnic and racial differences can effect on glycation of Hb and therefore lead to HbA 1 c variation (12, 14). Overall, HbA 1 c alone or combined with other GDM di- agnostic tests which can detect GDM during each trimester are unclear. Therefore, further studies are required for de- termine precise of HbA 1 c in GDM diagnose during preg- nancy in every trimester and ethnic groups. References 1. Hanna FW, Duff CJ, Shelley-Hitchen A, Hodgson E, Fryer AA. Diagnos- ing gestational diabetes mellitus: Implications of recent changes in diagnostic criteria and role of glycated haemoglobin (HbA1c). Clin Med (Lond). 2017;17(2):108–13. doi: 10.7861/clinmedicine.17-2-108. [PubMed: 28365618]. 2. Duke A, Yap C, Bradbury R, Hng TM, Kim C, Wansbrough A, et al. The discordance between HbA1c and glucose tolerance testing for the postpartum exclusion of diabetes following gestational diabetes. Dia- betes Res Clin Pract. 2015;108(1):72–7. doi: 10.1016/j.diabres.2015.01.006. [PubMed: 25661662]. 3. Mission JF, Catov J, Deihl TE, Feghali M, Scifres C. Early pregnancy dia- betes screening and diagnosis: Prevalence, rates of abnormal test re- sults, and associated factors. Obstet Gynecol. 2017;130(5):1136–42. doi: 10.1097/AOG.0000000000002277. [PubMed: 29016493]. 4. World Health Organization. Diagnostic criteria and classification of hyperglycaemia first detected in pregnancy. WHO/NMH/MND/ 13.2. Geneva: World Health Organization; 2013, [cited November 10 2016]. Available from: http://apps.who.int/iris/bitstream/10665/85975/1/ WHO_NMH_MND_13.2_eng.pdf . Copyright © 2018, International Journal of Health and Life Sciences. This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (http://creativecommons.org/licenses/by-nc/4.0/) which permits copy and redistribute the material just in noncommercial usages, provided the original work is properly cited.