الفهرس 
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Abstract
G
estational diabetes mellitus (GDM) is defined as any degree of glucose intolerance with onset or first recognition during pregnancy. GDM is characterized by insulin resistance or decreased glucose tolerance, which increases throughout pregnancy.
The rise in insulin resistance is likely to be caused by increasing amounts of hormones related to pregnancy, such as (placental lactogen, cortisol, estrogen, progesterone and possibly tumor necrosis factor from placenta) and changes in metabolism to meet the needs of the fetus. However, the entire causes are not clear, whereas normal pregnant women are capable of mounting an increased output of insulin to maintain euglycemia in the face of insulin resistance. Women destined to develop GDM appear to be unable to increase their insulin output to the same extent. The incidence of GDM depends on diagnostic criteria and varies widely between racial groups. The overall incidence of 3-6%has steadily increased over time, ranging from 2.2% in South America to 15% in the subcontinent of India.
Change in life style affect incidence of GDM, this change and its incidence is increasing in parallel with the epidemic of obesity and type II diabetes mellitus. The prevalence of GDM is increasing as pregnant women become older and more obese.
Control of blood glucose levels is of outmost importance during pregnancy. Uncontrolled glucose levels may result in complications for both mother and fetus. In patients with GDM, maternal complications such as hypertensive disorders are twice as likely; caesarean section delivery is needed in 13-32% of patients. There is a significant increase in the risk of type II DM later on in life.
The fetus from pregnancies with GDM has a higher risk of macrosomia (assoc iated with a higher rate of birth injuries), asphyxia, neonatal hypoglycemia and neonatal hyperinsulinemia. Uncontrolled GDM predisposes fetuses to accelerate and excessive fat accumulation, insulin resistance, pancreatic exhaustion secondary to prenatal hyperglycemia and possibly higher risk of child and adult obesity and type II DM later in adult life.
Prospective randomized data have recently demonstrated that treating women with GDM reduces the adverse perinatal outcomes. Additional support for treatment comes from a large retrospective study comparing women with treated GDM to women who were diagnosed later in pregnancy and were therefore “Untreated GDMs”. Outcomes were significantly better in the treated group than the untreated group.
There are no data showing how treatment affects later risks of type II diabetes mellitus in the mother and offspring. The main aims of treatment are to prevent fetal hyperinsulinemia and improve maternal endothelial function by reducing elevated maternal glucose levels. This is achieved by giving advice about diet and exercise initially, but women often require additional treatment, which has conventionally been insulin. The disadvantages of insulin for the mother include the need to give injections, frequent daily testing for monitoring, and risks of hypoglycemia, increase in appetite, weight gain and high cost.
Women may be anxious about being on insulin, and treatment compliance is an issue. It would be useful if there were alternative treatment options to insulin, preferably oral agents. Glyburide has been shown to be as effective as insulin in achieving maternal glycemic control in an open prospective randomized trial of 400 women with GDM. However, glyburide works by stimulating insulin secretion and is also associated with risks of maternal hypoglycemia and weight gain.
Metformin, an oral biguanide, may be a more logical alternative to insulin for women with GDM who are unable to cope with the increasing insulin resistance of pregnancy. Metformin works primarily by decreasing hepatic glucose output, improving peripheral glucose uptake, and decreasing free fatty acid levels, thus reducing insulin resistance without as much risk of resulting hypoglycemia.
Our study compared maternal weight gain during pregnancy in women with gestational diabetes, treated by insulin versus metformin. Our study found that the rate of maternal weight gain per week was statistically significantly higher in the metformin group compared to the insulin group. Fasting glucose levels were statistically significantly lower in the metformin group compared to the insulin group, albeit with minor clinical relevance. No statistically significant differences in postprandial glucose levels or glycosylated hemoglobin were found between the two groups. Incidence of caesarean section was statistically significantly higher in the insulin group compared to the metformin group. However, no statistically significant differences were found between both groups regarding gestational age at termination or incidence of amniotic fluid abnormalities, maternal hypoglycemia, preeclampsia, preterm labor, fetal demise and maternal ICU admission. No statistically significant differences were found between women of both groups regarding birth weight, 1-min and 5-min APGAR scores and incidence of NICU admission, congenital anomalies, macrosomia, birth trauma, respiratory distress and neonatal hypoglycemia, jaundice or hypocalcemia.