Indian Write-Ups
| Management |
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| Prevention Of Diabetes Starts Before Birth |
| - Dr.V.Seshiah, Dr.V.Balaji |
| The genetic predisposition and exposure to environmental factors precipitate many human ailments. This is beautifully described by the aphorism that the genes load the gun and environmental factors trigger off the manifestation of the diseases. Hence all along the effort has been to modify the environmental factors hoping to prevent or delay the development of diseases. This idea is slowly fading giving rise to the recent concept that many of the chronic diseases have fetal origin. Consequently, the attention at present is being focused on creating an ambient intrauterine environment. This approach may be the first step in the prevention of diseases like diabetes, hypertension and heart diseases. |
| Pregnancy is a unique tissue culture experience wherein the maternal metabolism has a critical implication for the fetal development. During pregnancy a new structure arises denovo and matures till it is expelled at the completion of gestational period. Throughout the pregnancy metabolic adaptation of the pregnant mother is to provide a constant fuel supply for the life and development of the fetus irrespective of whether she is fasting or feeding. Thus the fetus is considered to be a continuously feeding boarder in an intermittently eating host, the mother. |
| During the early weeks of the pregnancy the serum levels of female hormones estrogen and progesterone increase to promote the well-being and development of the fetus. As the pregnancy advances, the metabolic adaptation of the mother intensifies. They are mediated by increasing maternal levels of estrogen, progesterone, cortisol and lactogen. (The super female effect). These hormones cause progressive resistance to the action of insulin and blood sugar tends to rise. This tendency is counter balanced by the increased secretion of insulin by the pregnant women. These hormonal changes are designed to maintain the maternal blood glucose between 70 and 90mgm during fasting and 100-120mgm in the postprandial states (mean plasma glucose < 105 mg). In normal pregnancy blood sugar never exceeds this level. It is worth noting here that the blood sugar levels in normal pregnancy are less than the non-pregnant state due to increased insulin sensitivity and substrate deficiency particularly alanine for gluconeogenesis in the first half of pregnancy. |
| About three to ten percent of pregnant women develop gestational diabetes. In the later half of pregnancy the increasing tissue resistance to insulin action creates a demand for more insulin, which in a great majority of women is well within their secretory reserve of their beta calls, so that the balance between resistance to insulin and the available insulin is matched. If the beta cell reserve is not adequate and compensatory insulin elaboration does not occur to overcome this insulin resistance, glucose intolerance and gestational diabetes mellitus (GDM) occurs. This condition is defined as “glucose intolerance of varying severity with onset or first recognition during pregnancy ”. |
| Ideally all pregnant women should undergo screening for glucose intolerance and it is particularly important for Indian women, as they have high prevalence of diabetes and the relative risk of developing GDM is 11.3 times compared to White women. The American Diabetes Association recommends two procedures. One-Step approach, which involves straight away performing OGTT without prior screening. The other one is the Two-Step approach in which an initial screening is done by measuring the plasma glucose one hour after 50g glucose load (GCT) and performing a diagnostic OGTT with 100g glucose, if the GCT threshold value is more than 140mg.With either approach, the diagnosis of GDM is based on OGTT, either by 100g load or 75g load. (Table 1). GDM is diagnosed if two or more of the venous plasma glucose concentration meet or exceed the cut-off value recommended in Table 1. WHO recommends 2hr plasma glucose after 75g glucose load. The diagnosis of GDM is made if more than 140mg. The clinical implication of adverse pregnancy outcome is the same if the diagnosis of GDM is based on 2hr 75g OGTT, defined by either WHO or ADA. Hence the WHO screening procedure is recommended since it is simple and easier to perform. The screening procedure should be carried out between the 24th and 28th week and if negative repeated between the 30th and the 34th week. |
| The glucose intolerance during index pregnancy is not only associated with the increasing pregnancy morbidity but also increases the likelihood of subsequent diabetes in the mother. Gestational diabetes has a direct effect on the development of beta cells of the fetus and is associated with increased susceptibility to the development of obesity and diabetes in the offspring. As such, gestational diabetes has implication beyond the index pregnancy, identifying two generations (mother and her offspring) at risk of future diabetes. Further it has been observed that thirty percent of gestational diabetic women develop diabetes ten years after parturition. On prospective follow up by Diabetic Pregnancy Service of Madras Medical College 25.4 percent developed diabetes at the end of ten years. This progression from gestational diabetes to diabetes is two- fold if they become overweight, but maintaining the ideal body weight approximately halves the risk. |
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