Gestational diabetes mellitus and maternal-fetal health complications

Diabetes Mellitus in Pregnancy

Diabetes during pregnancy increases the risk for developing congenital anomalies by over 10 times. Maternal glycemic control is critical to prevent such abnormalities in the baby. When glycemic control is not achieved by dietary adjustments, commencing insulin therapy is strongly recommended. Regular monitoring of maternal glycemic levels and proper obstetric care should greatly help in reducing the potential health complications associated with diabetes during pregnancy.

Diabetes is the single most common complicating condition during pregnancy. [Rosenberg, (2005)] Gestational Diabetes Mellitus refers to the diagnosis of diabetes during pregnancy and it may be of either type 1 or type 2. In the United States 3 to 8 out of 100 pregnant women suffer from gestational diabetes. [Medline] In the UK also, 2 to 5% of all pregnancies involve gestational diabetes. [Alana Bluman, (2006)] Both gestational and pregestational diabetes carry huge maternofetal risk and hence early diagnosis and appropriate interventions aimed at maternal glycemic control are critical for the health of the mother and the proper development of the baby. I chose this topic for study as it carries huge health implications for the baby and the mother. From Hypoglycemia, respiratory distress syndrome and macrosomia to severe neurobehavioral abnormalities, diabetes during pregnancy causes a spectrum of health complications all of which could be avoided with early glycemic control. [Alana Bluman, (2006)] A brief overview of the pathophysiology, Clinical symptoms and a discussion of the implications for pregnant women and infants would provide a better insight into this important healthcare topic.

Pathophysiology of Diabetes

Diabetes Type 1 is due to the very low or total lack of insulin production. This is caused by destruction of the insulin producing beta cells due to environmental, genetic or autoimmune reactions. Of these, type IA, characterized by the presence of insulin and beta cell antibodies is the most common. Type 2 diabetes, or what is also known as non-insulin dependent diabetes, has a higher prevalence and affects mostly older adults. Environmental, genetic and metabolic factors are responsible for the onset of Type 2 Diabetes. However, high body mass index, obesity, lack of physical activity, unhealthy eating habits all contribute to the onset of Type 2 diabetes. Studies have shown that specific genes that are responsible for insulin sensitivity and beta cell actions maybe involved in the pathology of Type 2 diabetes. [Huether, S, (2008) pg 462]

Gestational Diabetes

In the early stages of pregnancy, certain natural changes occur in the hormonal secretions. In particular, estrogens and progestins act to reduce the glucose levels, increase fat deposition and increase appetite in pregnant women. However, with the advancing stages of pregnancy, the glucose levels start to surge while at the same time the insulin sensitivity gradually decreases. Particularly, hormones such as human placental Lactogen, Growth Hormone, and Corticotropin releasing hormone exhibit a profound insulin antagonizing effect. [Chapman L, (2010) pg 109] This implies that more insulin is needed to counteract the increasing glucose levels. Gestational diabetes results when the maternal insulin secretion is insufficient to balance the increasing postprandial glucose levels due to the pregnancy associated decline in insulin sensitivity. [Medscape, (2004)]

Clinical Symptoms

There are some common symptoms that could be attributed to gestational diabetes. These include frequent thirst, feeling of hunger, need for frequent urination, sudden blurred vision, etc. Since most of these symptoms are also commonly observed symptoms of pregnancy there is likelihood that these symptoms could be ignored. In most cases however, the doctor would prescribe a screening test for gestational diabetes if he suspects so. Also, prenatal examination would usually reveal a larger fetus size when compared to the normal size for the particular stage of pregnancy. However, the most common test is the 'Glucose tolerance test', which is usually done between the 24th and 28th week of pregnancy. [Alana Bluman, (2006)]

Laboratory Diagnosis

The clinical diagnosis of gestational diabetes is usually done using the 'glucose tolerance tests'. The 'fasting blood glucose test', 'screening glucose challenge test' or the 'oral glucose tolerance test' may be used. For the screening glucose challenge test the doctor will give a sugar drink and test the blood glucose level an hour later. For oral glucose tolerance test, the patient is asked to fast for 8 hours (only water permitted) and then the doctor gives a sugary beverage to drink. Blood glucose levels are monitored on a hourly basis for three hours. Glucose levels exceeding 180 mg/dl for the first hour, 155 mg/dl at the second hour or 140 mg/dl at the third hour are considered abnormal. Usually if the glucose levels are higher than 180 mg/dl at 1 hour in an oral glucose tolerance test the doctor may also require a fasting glucose test. If the fasting glucose level is also greater than 95 mg/dl then it is important that treatment for gestational diabetes is immediately commenced. [NDIC, 2006]

Implications for the Infant

Infants of mothers with GDM carry a high risk for perinatal morbidity and mortality. A variety of conditions including, respiratory distress syndrome, macrosomia, jaundice, hypoglycemia and fetal distress are possible fetal complications. Hyperactivity, 'delayed brain maturity' and impaired motor functions are also observed. There is also a higher risk factor for shoulder dystocia among the infants, which further increases the risk for developing brachial plexus injury. To avoid all these complications regular ultrasound screening of the fetus is important. If the physician feels that macrosomia maybe a problem, then caesarian section should be performed which could help avoid brachial plexus injury. [Deborah L. Conway, 2007]

Conclusion

Gestational diabetes is a condition characterized by decreased insulin sensitivity and insufficient insulin production in pregnant women. Though potentially dangerous, the condition could be effectively managed by simple dietary changes and appropriate physical activities. Low glycemic carbohydrate food content, low fat intake, regular meals and physical activity could be very effective in achieving the required glycemic control. Diabetes during pregnancy increases the risk for developing congenital anomalies by over 10 times. [Alana Bluman] Maternal glycemic control is critical to prevent such abnormalities in the baby. Therefore fasting and proprandial glucose levels should be regularly monitored. In cases where glycemic control is not achieved by dietary adjustments, commencing insulin therapy is strongly recommended. It is also essential to monitor the fetal health using ultrasound screening to avoid any complications during delivery of the baby. Regular monitoring of maternal glycemic levels and proper obstetric care should greatly help in reducing the potential health complications associated with diabetes during pregnancy.