GESTATIONAL DIABETES

Prepared by dr.kucha

Gestational Diabetes

This diagnosis is given when a woman, who has never had diabetes before, gets diabetes or has high blood sugar, when she is pregnant. Its medical name is gestational diabetes mellitus or GDM.It is one of the most common health problems for pregnant women.The word “gestational” actually refers to “during pregnancy.”

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As the incidence of type 2 diabetes accrues with age and is unmasked by other diabetogenic factors, that is, obesity, it is likely that both pregnancy aggravation and impending insulinopenia are involved.

CHO MetabolismEffects of Pregnancy *Mild fasting hypoglycemia; *Post prandial hyperglycemia Due to increase in plasma volume in early

gestation and increase in fetal glucose utilization.

As pregnancy advances -Progressive increase in tissue resistance to insulin– Increase insulin secretion to maintain

euglycemia– Suppressed glucagon response– Inc. prolactin, cortisol– HPL has GH like effects

‘Endocrinology of Pregnancy’

The placenta produces larger quantities of more hormones than any other human organ:– Human placental lactogen– Estrogen / progesterone

The majority of its products are released into the maternal circulation to induce changes on the fetuses’ behalf.

Glucose Metabolism in Pregnancy

Fetal growth is dependent upon maternal glucoseCarbohydrates from maternal dietStored glycogen converted to glucoseHigh levels of glucose transported by diffusion to the fetusFetal production of insulin

Glucose Metabolism in PregnancyFirst Half of Pregnancy (Anabolic)– Pancreatic beta-cell hyperplasia causes

hyperinsulinemia – Increased uptake and storage of glucose

Second Half of Pregnancy (Catabolic)– Placental hormones block glucose receptors

and cause insulin resistanceIncreased lipolysisIncreased gluconeogenesisDecreased glycogenesis

– Increased glucose and amino acids for the fetus

Pedersen Hypothesis (1952)

Maternal hyperglycemia

Fetal hyperglycemia

Fetal hyperinsulinemia

Excess fetal fat

Maternal and Fetal EffectsThe American College of Obstetricians and Gynecologists (2000) defines macrosomic infants as those whose birthweight exceeds 4500 g. The perinatal goal is avoidance of difficult delivery due to macrosomia, with concomitant birth trauma associated with shoulder dystocia. Except for the brain, most fetal organs are affected by the macrosomia that commonly characterizes the fetus of a diabetic woman.

Neonates born from women with consistently high blood sugar levels are also at an increased risk of low blood glucose (hypoglycemia), jaundice, high red blood cell mass (polycythemia) and low blood calcium (hypocalcemia) and magnesium (hypomagnesemia).Untreated GDM also interferes with maturation, causing dysmature babies prone to respiratory distress syndrome due to incomplete lung maturation and impaired surfactant synthesis.

The most important perinatal concern is excessive fetal growth, which may result in both maternal and fetal birth trauma. More than half of women with gestational diabetes ultimately develop overt diabetes in the ensuing 20 years, and there is mounting evidence for long-range complications that include obesity and diabetes in their offspring.

There is extensive evidence that insulin-like growth factors I (IGF-I) and II (IGF-II) also play a role in the regulation of fetal growth (see Chap. 38, Normal Fetal Growth). These growth factors, which structurally are proinsulin-like polypeptides, are produced by virtually all fetal organs and are potent stimulators of cell differentiation and division

Maternal hyperglycemia prompts fetal hyperinsulinemia particularly during the second half of gestation, which in turn stimulates excessive somatic growth. Macrosomia results. Similarly, neonatal hyperinsulinemia may provoke hypoglycemia within minutes of birth

Other factors implicated in macrosomia include epidermal growth factor, leptin, and adiponectin Maternal obesity is an independent and more important risk factor for large infants in women with gestational diabetes than is glucose intolerance

Gestational Diabetes

It occurs in about 5% of all pregnancies.

If not treated, gestational diabetes can cause health problems for the mother and the fetus.

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Gestational Diabetes

Risk Factorsmaternal age >25Family historyglucosuriaprior macrosomiaprevious unexplained stillbirthethnic group: Hispanic, Black, Asians

Screening

Screening should be performed between 24 and 28 weeks in those women not known to have glucose intolerance earlier in pregnancy.This evaluation is usually done in two steps. In the two-step procedure, a 50-g oral glucose challenge test is followed by a diagnostic 100-g oral glucose tolerance test (OGTT) if initial results exceed a predetermined plasma glucose concentration.

Fifth International Workshop-Conference on Gestational Diabetes: Recommended Screening Strategy Based on

Risk Assessment for Detecting Gestational Diabetes (GDM)

GDM risk assessment: Should be ascertained at the first prenatal visit

Low Risk: Blood glucose testing not routinely required if all the following are present: Member of an ethnic group with a low prevalence of GDM No known diabetes in first-degree relatives Age < 25 years Weight normal before pregnancy Weight normal at birth No history of abnormal glucose metabolism No history of poor obstetrical outcome

Average RiskPerform blood glucose testing at 24 to 28 weeks using either:

—Two-step procedure: 50-g oral glucose challenge test (GCT), followed by a diagnostic 100-g oral glucose tolerance test for those meeting the threshold value in the GCT. —One–step procedure: Diagnostic 100-g oral glucose tolerance test performed on all subjects.

High Risk: Perform blood glucose testing as soon as feasible, using the procedures described above if one or more of these are present:

—Severe obesity —Strong family history of type 2 diabetes —Previous history of GDM, impaired glucose metabolism, or glucosuria. If GDM is not diagnosed, blood glucose testing should be repeated at 24 to 28 weeks or at any time there are symptoms or signs suggestive of hyperglycemia

Diagnosis

Recommended criteria for interpretation of the 100-g diagnostic glucose tolerance test are shown in Table 52-4. Also shown are the criteria for the 75-g test most often used outside the United States, but increasingly used in this country

Management

Women with gestational diabetes can be divided into two functional classes using fasting glucose levels. Insulin therapy is usually recommended when standard dietary management does not consistently maintain the fasting plasma glucose at < 95 mg/dL or the 2-hour postprandial plasma glucose < 120 mg/dL

Whether insulin should be used in women with lesser degrees of fasting hyperglycemia—105 mg/dL or less before dietary intervention—is unclear because there have been no controlled trials to identify ideal glycemia targets for prevention of fetal risks. The Fifth International Workshop Conference on Gestational Diabetes, however, recommended that maternal capillary glucose levels be kept 95 mg/dL in the fasting state

The American Diabetes Association (ADA) (2000) has recommended nutritional counseling with individualization based on height and weight and a diet that provides an average of 30 kcal/kg/d based on prepregnant body weight for nonobese women. Although the most appropriate diet for women with gestational diabetes has not been established, the ADA has suggested that obese women with a body mass index (BMI) > 30 kg/m2 may benefit from a 30-percent caloric restriction. This should be monitored with weekly tests for ketonuria, because maternal ketonemia has been linked with impaired psychomotor development in offspring

Exercise

exercise is known to be important in nonpregnant patients exercise improves cardiorespiratory fitness without improving pregnancy outcome. physical activity during pregnancy reduced the risk of gestational diabetes. exercise diminishes the need for insulin therapy in overweight women with gestational diabetes.

researchers' findings support the common practice of self blood-glucose monitors for women with gestational diabetes who are treated with diet alone.Postprandial surveillance for gestational diabetes has been shown to be superior to preprandial surveillance

Insulin

Insulin given to decrease complications related to macrosomia in women with gestational diabetes and fasting euglycemia has long been controversial

Most initiate insulin therapy in women with gestational diabetes if fasting glucose levels exceeding 105 mg/dL persist despite diet therapy. Experts differ in their approach to insulin therapy in gestational diabetes. A total dose of 20 to 30 units given once daily, before breakfast, is commonly used to initiate therapy. The total dose is usually divided into two-thirds intermediate-acting insulin and a third short-acting insulin. Alternatively, weight-based split-dose insulin is administered twice daily. Once therapy has been initiated, it must be recognized that the level of glycemic control to reduce fetal and neonatal complications has not been established.

Oral Hypoglycemic Agents

The American College of Obstetricians and Gynecologists (2001) has not recommended these agents during pregnancy. Metformin has been used as treatment for polycystic ovarian disease and has been reported to reduce the incidence of gestational diabetes in women who use the drug throughout pregnancy

Insulin Treatment

Insulin is used for overtly diabetic pregnant women. Although oral hypoglycemic agents have been used successfully for gestational diabetes (Oral Hypoglycemic Agents), these agents are not currently recommended for overt diabetes except on an investigational basis (American College of Obstetricians and Gynecologists, 2005). Maternal glycemic control can usually be achieved with multiple daily insulin injections and adjustment of dietary intake. The action profiles of commonly used insulins are shown in Table 52-10

It is important to considerably reduce or delete the dose of long-acting insulin given on the day of delivery. Regular insulin should be used to meet most or all of the insulin needs of the mother at this time, because insulin requirements typically drop markedly after delivery. We have found that continuous insulin infusion by calibrated pump is most satisfactory (Table 52-13).

During labor and after delivery, the woman should be adequately hydrated intravenously and given glucose in sufficient amounts to maintain normoglycemia. Capillary or plasma glucose levels should be checked frequently, and regular insulin should be administered accordingly. It is not unusual for a woman to require virtually no insulin for the first 24 hours or so postpartum and then for insulin requirements to fluctuate markedly during the next few days. Infection must be promptly detected and treated.

Table 52-5. Glyburide Treatment Regimen for Women with Gestational Diabetes Who Fail Diet

Therapy

1. Glucometer blood glucose measurements fasting and 1 or 2 hours following breakfast, lunch, and dinner.

2. Glucose level goals (mg/dL): Fasting < 100, 1-h < 155, and 2-h < 130.

3. Glyburide starting dose 2.5 mg orally with morning meal.4. If necessary, increase daily glyburide dose by 2.5-mg/wk

increments until 10 mg/d, then switch to twice-daily dosing until maximum of 20 mg/d reached. Switch to insulin if 20 mg/d does not achieve glucose goals.

Postpartum EvaluationThe Fifth International Workshop Conference on Gestational Diabetes recommended that women diagnosed with gestational diabetes undergo evaluation with a 75-g oral glucose tolerance test at 6 to 12 weeks postpartum and other intervals thereafter (Metzger and associates, 2007). These recommendations are shown in Table 52-6 along with the classification scheme of the American Diabetes Association (2003).

Women with a history of gestational diabetes are also at risk for cardiovascular complications associated with dyslipidemia, hypertension, and abdominal obesity—the metabolic syndrome (see Chap. 43, The Metabolic Syndrome).

Akinci and associates (2009) reported that a fasting glucose level 100 mg/dL with the index OGTT was an independent predictor of the metabolic syndrome.

Contraception

Low-dose hormonal contraceptives may be used safely by women with recent gestational diabetes . The rate of subsequent diabetes in oral contraceptive users is not significantly different from that in those who did not use hormonal contraception

References

Adasheck JA, Lagrew DC, Iriye BK, et al: The influence of ultrasound examination at term on the rate of cesarean section. Am J Obstet Gynecol 174:328, 1996 

Akinci B, Celtik A, Yener S, et al: Prediction of developing metabolic syndrome after gestational diabetes mellitus. Fertil Steril January 13, 2009 [Epub ahead of print] 

Albert TJ, Landon MB, Wheller JJ, et al: Prenatal detection of fetal anomalies in pregnancies complicated by insulin-dependent diabetes mellitus. Am J Obstet Gynecol 174:1424, 1996 [PMID: 9065106]

Almario CV, Ecker T, Moroz LA, et al: Obstetricians seldom provide postpartum diabetes screening for women with gestational diabetes. Am J Obstet Gynecol 198:528.e1, 2008 

American College of Obstetricians and Gynecologists: Gestational diabetes. Practice Bulletin No. 30, September 2001

American College of Obstetricians and Gynecologists: Pregestational diabetes mellitus. Practice Bulletin No. 60, March 2005

American Diabetes Association: Medical Management of Pregnancy Complicated by Diabetes, 2nd ed. Jovanovic-Peterson L (ed). Alexandria, VA, American Diabetes Association, 1995

American Diabetes Association: Clinical practice recommendations, 1999. Diabetes Care 23:S10, 1999a

American Diabetes Association: Report of the Expert Committee on the Diagnosis and Classification of Diabetes Mellitus. Diabetes Care 22:512, 1999b