Relation of insulin like growth factor and glycocylated hemoglobin at different gestational periods of pregnancy in diabetic pregnant women

Background : Diabetes mellitus complicating pregnancy is one of the most common antenatal complications that are associated with significant perinatal mortality and morbidity. Insulin like growth factor-1 (IGF-1) has been implicated with micro-vascular complications during pregnancy. Glycosylated hemoglobin (HbA1c) is a reliable index, used to evaluate the glycemic control at the last 8 weeks. Aim : To find the relation between the level of insulin like growth factor and HbA1c at different gestational periods of pregnancy in diabetic pregnant women. 190 pregnant They were 134 pregnant women with abnormal and 56 healthy pregnant Those of abnormal carbohydrate into two those with gestational diabetes mellitus and those with pregestational diabetes mellitus and levels in the studied women at the and of Results : IGF-1 concentrations was found to be higher in patients with GDM when compared with those of PGDM and the control groups, in both 2nd and 3rd trimesters with a significant (P <0.001) difference among subgroups. HbA1c concentrations were found to be significantly (P< 0.001) higher in pregnant women with GDM and PGDM than in the control group. There was a significant (r=0.27, P<0.001) weak correlation between IGF-1 and HbA1c in both 2nd and 3rd trimesters.


Introduction
Diabetes mellitus complicating pregnancy is one of the most common antenatal complications that are associated with significant preinatal mortality and morbidity [1,2]. Diabetic pregnancies can be divided into two categories: those with pre-gestational or pre-existing diabetes mellitus in which the diagnosis is made in the pre-pregnancy state (PGDM), and those with gestational diabetes mellitus (GDM). Pre-existing diabetes consists of type 1 diabetes mellitus with an incidence of around 0.5%, and type 2 diabetes with an incidence of 2-3% [4]. The incidence of gestational diabetes mellitus differs in different populations and ethnic groups, and was shown to be as high as 13% in Chinese populations [4,5]. Effective treatment of preexisting as well as gestational diabetes mellitus was shown to improve outcome and reduce perinatal mortality, as compared to untreated patients [6].
An atherogenic factor that promotes vascular endothelial growth, IGF relating to its ability of NO production [7].
IGF-1, also called somatomedin C, is a protein that in human is encoded by the IGF1 gene [8].
IGF-1 is a hormone similar in molecular structure to insulin. It plays an important role in childhood growth and continues to have anabolic effects in adults. A synthetic analog of IGF-1, mecasermin is used for the treatment of growth failure [9]. It is a 70amino acid peptide in a single chain protein having a molecular mass of 7649 Dalton, with a structure similar to insulin, particularly proinsulin, and an ability to bind with its receptor although with lesser affinity. The IGF-1 receptor is also composed, like the insulin receptor, of 2 chains, α and β, and is related to tyrosine kinase activity, hence there is a possibility of exerting similar clinical effects by both hormones [10]. IGF-1 is shown to be varied [13].
HbA1c was introduced into a clinical use in the 1980s and subsequently has become a cornerstone of clinical practice. It reflects average plasma glucose over the previous 8-12 weeks [14]. It is the preferred test for assessing glycaemic control in people with diabetes. Moreover, there has been substantial interest in using it as a diagnostic test for diabetes and as a screening test for persons at high risk of diabetes [15]. Before pregnancy, the target for metabolic control in women with diabetes is HbA1c [16]. Increased thirdtrimester HbA1c levels are associated with an increased risk of preeclampsia, macrosomia [17], and still birth [18], leading to speculations that the target for HbA1c in pregnancy should be even lower than outside pregnancy to prevent adverse events.

Methods
The studied 190 pregnant women were of a single viable fetus and cephalic. in both 2nd and 3rd trimesters (Fig 1 & 2). shown that the concentrations of IGF-1 was significantly higher in women with GDM than in the control group [24].
In the current study the mean ± SD of HbA1c in GDM, PGDM in the 3rd trimester were 6.29±0.78% and 6.27±0.87% respectively compared to the control group    First, a decrease in the fasting blood glucose occurs in early pregnancy, mainly between weeks 6 and 10, and is sustained during the remaining part of pregnancy [25][26]. Second, new erythrocytes formed will therefore be exposed to a lower timeaveraged glucose concentration than those of non-pregnant women, and the degree of glycosylation might therefore be less [27].
Third, the erythrocyte lifespan is likely to be decreased in pregnancy, hence reducing the HbA1c value [28]. Our values were in agreement with previous findings [25].
Compared to other studies, the present study results of the control group were consistent with those reported by Redder & Roosmalen [29]. Moreover, the mean values of HbA1c in PGDM were close to finding of Marek Pietryga et al. [30]; who found no significant difference between mean values of HbA1c in pregnant women with and without vascular complications. On the other hand, our results were higher than those obtained by Usama et al. [31]. Similarly, our results of GDM were higher than those obtained by Capula et al. [32]. Differences may be due to variations in management protocols.
In conclusion, both, IGF-1 and HbA1c levels elevate in pregnant women with GDM and PGDM, such rise is manifested by a weak positive correlation between the concentrations of the two parameters. It is recommended to study the role of IGF-1 therapy in pregnant with diabetes mellitus especially those with vasculopathy.