Hemoglobin concentration and iron supplement during pregnancy were associated with an increased risk of gestational diabetes mellitus

Abstract

Background Hemoglobin (Hb) measurement is a conventional test during perinatal visits. Hb concentration is related to iron supplement. However, studies focusing on Hb levels, iron supplement, and pregnancy outcomes are scarce. This study aimed to determine whether Hb levels and iron supplement were associated with the risk of gestational diabetes mellitus (GDM). Methods A running hospital‐based cohort was conducted from August, 2011. The demographic data and medical information were collected individually through questionnaires and patient medical records. Multiple linear regression was applied for the association between Hb levels, iron supplement, and blood glucose. Multiple logistic regression was used for evaluating odds ratios between Hb levels, iron supplement, and GDM. Results Hb levels during first (T1) and second trimester (T2) of pregnancy were significantly and positively associated with blood glucose and GDM risk. After adjusting for age, prepregnancy body mass index, and other risk factors, pregnant women with Hb ≥ 11 g/dL and iron supplement had higher postprandial blood glucose at 1 hour (Hb ≥ 11 g/dL in T2 and iron supplement in T1: β = 0.860，P = <0.001; Hb ≥ 11 g/dL in T2 and iron supplement in T2: β = 0.960，P < 0.001; Hb ≥ 11 g/dL in T1 and iron supplement in T2: β = 1.133, P = 0.033) and GDM risks (odds ratio [OR] = 1.53, 95% confidence interval [CI]: 1.05‐2.24; OR = 1.92, 95% CI: 1.13‐3.35; OR = 2.15, 95% CI: 1.07‐4.34, respectively), compared with those with Hb < 11 g/dL and without iron supplement. Conclusion High Hb concentration and iron supplements without anemia increased postprandial blood glucose and risks for GDM. It indicates that pregnant women with good Hb levels should not be advised to take iron supplements during pregnancy.

Red Blood Cells in The First Trimester and The Risk of Gestational Diabetes: A Prospective Cohort Study

“…Moreover, the changes of RBC and Hb from the early pregnancy to the second trimester were observed, in which the RBC and Hb concentrations in the second trimester were decreased. RBC and Hb concentrations in the second trimester were also found to be associated with the incidence of GDM, which was consistent with previous studies [20,27]. These ndings emphasized that increased RBC and Hb concentration during pregnancy were probably related to the pathologic effects of GDM in addition to its normal changes.…”

Effects of multi‐metal exposure on the risk of diabetes mellitus among people aged 40–75 years in rural areas in southwest China

“…A study that used Mendelian randomization found a causal relationship between increased systemic Fe status and increased prevalence of type 2 diabetes mellitus by analyzing serum Fe, ferritin, transferrin and transferrin saturation levels in 74,124 type 2 diabetes mellitus cases and 824,006 controls 48 . Furthermore, many studies have found that the higher the Fe exposure level is in women during pregnancy, the higher the prevalence of gestational diabetes mellitus is 49 , 50 , 51 , 52 , 53 . These findings are consistent with the present results that Fe exposure level is positively correlated with IFG rate and diabetes mellitus prevalence.…”

A study to investigate the elevated maternal haemoglobin value as a risk biomarker for gestational diabetes: A nested case control study

“…Characteristics like parity, physical exercises, and pregnancy supplements intake and family history were equally distributed among the groups. 13,14 While comparing height, weight, body mass index (BMI), diastolic blood pressure and systolic blood pressure, both GDM and non-GDM groups showed an identical distribution. A study Shah A et al conducted to identify the association between the GDM, and BMI based on race and ethnicity.…”

“…The 2hr OGTT values were performed, and the results were statically significant among the groups, and the studies like Si S et al, Kabade SD et al, and Rayis DA et al have the reported the same. 4,13,16 Lao TT et al, conducted a study in Chinese population found that the 18.7% of the quartile population with haemoglobin greater that 13 g/dL and 13.2% of the population developed GDM whose haemoglobin values between the range 12.4 g/dL to 13 g/dL. Rayis DA et al conducted a study and concluded that haemoglobin greater than 10.8 g/dL are at risk of development GDM.…”