Several studies have shown a strong correlation between pGDM and MS. Even Anila Verma et al. and Baris Akinci et al. have postulated pGDM as a risk factor for development of metabolic syndrome
[21, 22]. On the other hand, L. Chatzi and his colleagues have suggested that metabolic syndrome in first trimester could be a risk factor for the development of GDM in late pregnancy
. Also in a prospective study by Wolf et al. it was shown that high CRP levels in the first trimester of pregnancy are associated with the increased risk of pGDM, independent from other risk factors such as age, multiparity and smoking
. In our research we have tried to explain this discrepancy in means of MS, pGDM and inflammatory markers.
In this investigation the prevalence of MS in women with pGDM was about three folds higher than the control group, which is in concordance with the findings of other studies such as Lauenborg’s
. In our study, the mean serum levels of CRP, interleukin 6, HOMA-IR and LDL-C in pGDM women were higher than the control group. Since the increase in these markers is shown to be a risk factor for cardiovascular diseases, this could explain the findings of some studies in which pGDM was defined as a chronic condition that leads to the increased risk of cardiovascular disease
[6–8]. Winzer et al. in their study found that in women with pGDM and metabolic syndrome, interleukin-6 level was higher than the group without metabolic syndrome and pGDM
According to the findings of this study, the mean levels of CRP were higher in women with BMI ≥ 25 kg/m2 than those who had BMI<25 kg/m2. Several epidemiological studies have shown a strong correlation between CRP levels and BMI: the higher the BMI, the higher the level of CRP
[26–28]. However, Ferraz et al. could not find this correlation although they found out that the mean CRP levels in women with high waist circumference was significantly higher than those with low waist circumference (with the cut-off of 88 cm)
As we have shown C-reactive protein was not independently correlated with fasting blood glucose levels. This is in accordance with a study in Brazilin women
. However, King et al.
 showed a significant correlation between CRP and FBS. This discrepancy might be ascribed to the differences in methodology, which means the lag time between the survey and delivery, and method of participant selection. For the former reason it is to say that since our examination was carried out earlier than the other studies (12–24 months after delivery compared with 5–11 years after delivery this shorter lag time might have caused this discrepancy. It comes from other studies that there is a correlation between this lag time and the development of diabetes. The longer this period, the higher will be the incidence of type 2 DM
[5, 30]. Also, diabetic women had been excluded from our study.
As we have shown, the known risk factors of subclinical atherosclerosis or cardiovascular disease such as mean levels of CRP, interleukin 6, HOMA-IR, FBS, and LDL-C were compared between the four groups with following features: the first group: without history of GDM and MS, the second group: women with pGDM but without MS; the third group: women with MS but without the history of pGDM; and the last group: women with both MS and the history of pGDM.
There has also been a positive correlation between the number of MS components and CRP level, so that in those who have all five components of MS, CRP levels are four times higher than those who have only four components of it. This finding is in concordance with that of Ferraz et al.
. There were also similar findings about interleukin 6 in our investigation (the results are not shown).
The relationship between inflammatory markers, pGDM and metabolic syndrome has been poorly studied. We could not find any differences in CRP levels between the first group (i.e. without the history of pGDM and MS) and the second group (only with the history of pGDM/without MS). Additionally, there was no significant difference in CRP level of the first and the third group (without MS and history of pGDM, and with MS without history of pGDM, respectively). But the first and fourth group (women with pGDM and MS) were different in terms of CRP level. It means, CRP was higher when the history of pGDM and MS were present compared with those without these two components. The results of this study revealed that in pGDM women who have MS components too, CRP levels increase more than 5 times, compared with women without MS and pGDM. Considering interleukin 6 concentrations between the 4 mentioned groups, it was shown that the mean level of interleukin 6 in the fourth group was about 2 times higher than the third and second groups.
In addition, we found that BMI and particularly waist circumference were associated with CRP levels. This is compatible with studies of other investigators who also found that when the history of pGDM co-exists with MS, there is a synergistic effect on the elevation of serum levels of inflammatory markers. They showed that increased levels of inflammatory markers in MS and pGDM may be related to visceral obesity. Any increase in fat tissue, particularly in abdominal viscera, could lead to the activation of inflammatory cascade