effect of the placental hormones, gestational diabetes mellitus (GDM) results. with a higher rate of type 2 diabetes mellitus, such as African Americans, …
Diabetes
Gestational Diabetes
5 Gestational Diabetes
Created: July 7, 2004
During pregnancy there are many changes that take place in the mothers metabolism–a rise in insulin resistance is one of these changes The placenta supplies a growing fetus with nutrients and produces a variety of hormones to maintain the pregnancy Some of these hormones, such as human placental lactogen, have a blocking effect on insulin that usually begins 20 to 24 weeks into the pregnancy The contra-insulin effect of placental hormones leads to higher levels of maternal blood glucose after eating postprandial levels that may aid fetal growth Normally, the mothers beta cells can produce additional insulin to overcome the insulin resistance of pregnancy As the placenta grows, more hormones are produced, and insulin resistance becomes greater When the mothers production of insulin is not enough to overcome the effect of the placental hormones, gestational diabetes mellitus GDM results GDM is defined as carbohydrate intolerance of varying degrees of severity with onset or first recognition during pregnancy 1 GDM complicates 7 of all pregnancies in the United States 2 and is more common in populations with
a higher rate of type 2 diabetes mellitus, such as African Americans, Asian Americans, Hispanic Americans, and Native Americans 3, 4 The main complications of GDM are increased fetal size, which may complicate delivery, and hypoglycemia in the baby immediately after delivery Women with GDM generally have normal blood sugar levels during the critical first trimester before the 13th week of pregnancy This is in contrast to patients with type 1 diabetes, where hyperglycemia in this period may cause congenital birth defects After a positive screening test, the diagnosis of GDM is made by a glucose tolerance test In this test, a sugary drink is given, and a series of blood tests are taken at set time intervals Table 1 If hyperglycemia is detected, treatment begins with a change in diet and an increase in exercise If these lifestyle changes fail to control blood glucose levels, insulin therapy is started Women with pre-existing diabetes require higher doses of insulin during pregnancy because of the increase in insulin resistance If their diabetes is usually controlled using oral hypoglycemic agents, they are usually transferred to insulin to enable better glucose control and because the
safety of most hypoglycemic agents has not been studied in pregnancy GDM can disappear within hours of giving birth, depending on individual factors such as beta cell function and predisposing factors such as obesity However, a significant portion of women go on to develop type 2 diabetes Because GDM and type 2 diabetes both feature insulin resistance and share risk factors such as obesity, it is possible that these two conditions may also share diabetes susceptibility genes
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Diabetes
Gestational Diabetes
References
1 Metzger BE, Coustan DR et al Summary and recommendations of the Fourth International WorkshopConference on gestational diabetes mellitus Diabetes Care 21 suppl2:B161B167; 1998 PubMed 2 Gabbe SG, Graves CR et al Management of diabetes mellitus complicating pregnancy Obstet Gynecol 102:857868; 2003 PubMed 3 Engelgau MM, Herman WH, Smith PJ et al The epidemiology of diabetes and pregnancy in the US, 1988 Diabetes Care 18:10291033; 1995 PubMed 4 Gestational diabetes mellitus Diabetes Care 26 Suppl 1:S103S105; 2003 PubMed Table 1 Diagnosis of gestational diabetes
mg/dl Glucose load, 100 g Fasting 1 hour 2 hours 3 hours Glucose load, 75 g Fasting 1 hour 2 hours
mmol/l
95 180 155 140 95 180 155
53 100 86 78 53 100 86
Gestational diabetes can be diagnosed using either a 100-g or 75-g oral glucose load Two or more of the venous plasma glucose concentrations must be met or exceeded for a positive diagnosis The test should be done in the morning after an overnight fast
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Source:ncbi.nlm.nih.gov
