A Case of Preeclampsia
Susan is a 19-year-old “meat-and-potato” type eater who rarely consumes vegetables, fruits, or dairy products. She likes monosyllabic vegetables (beans, corn, and peas), bananas and oranges, and chocolate milk. She generally consumes one of these vegetables and fruits each day, and always has a glass of chocolate milk. Susan consumes sweetened iced tea throughout the day, and twice a week she eats rice with meat rather than potatoes. She finds this type of diet satisfying and rarely consumes foods other than those mentioned.
Her first 17 weeks of pregnancy were uneventful. At week 18 she was found to have proteinuria. By week 22, her blood pressure had increased to 150/100 mm Hg, and she was diagnosed with preeclampsia. Laboratory studies indicated that her blood glucose level was on the high side of normal and that she was insulin resistant. She was lost to follow-up after her week 22 visit.
A bit overweight prior to pregnancy, Susan did not gain weight and restricted her salt intake after midpregnancy. She believed these actions would help lower her weight and blood pressure. Although she was given a supply of prenatal vitamin and mineral supplements early in pregnancy, she rarely remembered to take them. Her baby, weighing 5 pounds 5 ounces (2380 grams), was delivered by cesarean section at week 36.
Questions
1. List three ways in which Susan’s dietary intake likely contributes to oxidative stress.
2. Identify two other characteristics of her diet that are contraindicated for women with preeclampsia. Answers should be different than those for question 1.
3. List three health problems Susan is at increased risk of developing due to her history of preeclampsia.
(Answers are located in the Instructor’s Manual for the 4th edition of Nutrition Through the Life Cycle.)
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production to lower those levels. The higher the level of blood glucose received, the larger the fetal output of insulin.
Potential Consequences of Gestational Diabetes
Potential consequences as-sociated with gestational diabetes are summarized in Table 5.7. Elevated hemo-globin A1c levels, a long-term marker of blood glucose concentrations, indicate poor glucose control and higher risk of adverse outcomes.
Specifically, hemoglobin A1c levels over 8% are associated with higher rates of sponta-neous abortion, stillbirth, ne-onatal death, and congenital anomalies than are values
Hemoglobin A1c A form of hemoglobin used to identify blood glucose levels over the lifetime of a red blood cell (120 days).
Glucose molecules in blood will attach to hemoglobin (and stay attached). The amount of glucose that attaches to hemoglobin is proportional to levels of glucose in the blood. The normal range of hemoglobin A1c is 4 to 5.9%. Also called glycosylated hemoglobin and glycated hemoglobin.
Congenital Anomalies Structural, functional, or metabolic abnormalities present at birth. Also called congenital abnormalities.
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mothers are heavier at birth, have higher body mass in-dex (BMI) throughout childhood, and have 7–20 times greater incidence of type 2 diabetes in early adulthood.
Although risks of these conditions increase in offspring of women with poorly controlled diabetes in general, the pronounced effect in Pima Indians is likely due to a strong genetic tendency toward insulin resistance and obesity.60
The end of pregnancy initially restores insulin sensi-tivity in most women with gestational diabetes. However, a degree of insulin resistance often remains.37 Close to half of women with gestational diabetes in a previous preg-nancy will develop it in a subsequent pregpreg-nancy.61 Women with weight gain after pregnancy and repeated pregnancies continue to experience insulin insufficiency and resistance;
this group is at even higher risk of developing type 2 dia-betes later in life. Among women who have experienced gestational diabetes, those requiring insulin therapy have higher blood pressure than women whose gestational dia-betes was controlled with diet and exercise.37
Risk Factors for Gestational Diabetes
Both type 2 and gestational diabetes are linked to multiple inherited predispositions and their environmental triggers, such as excess body fat and low physical activity levels.64 Results of a large prospective study indicate that the risk for gestational diabetes decreases 26% for each 10 grams of fiber consumed daily from plant sources. Diets both low in cereal fiber and high in glycemic load are associ-ated with a 2.15-fold increased risk compared to diets high in cereal fiber and low in glycemic load.63 About half of women who develop gestational diabetes have no iden-tified risk for the disease.64 Risk factors for gestational diabetes are outlined in Table 5.8.
Diagnosis of Gestational Diabetes
The diagnosis of gestational diabetes is based on abnormal blood glucose levels. Glucose screening is recommended for women at high risk of gestational diabetes at the initial visit or as soon as possible thereafter. High risk is identi-fied in women who have one or more of the following:
Marked obesity
●
Diabetes in a mother, father, sister, or brother
●
History of glucose intolerance
●
Previous macrosomic infant
●
Current glucosuria
●
A 50-gram oral glucose challenge test is generally used for blood glucose screening. This test can be done without fasting. Blood is collected 1 hour after the glu-cose load is consumed and tested for gluglu-cose content. This test should be followed by an oral glucose tolerance test if below 7%.57 Exposure to high insulin levels in utero leads
to increased glucose uptake into cells and the conversion of glucose to triglycerides. These changes increase fetal forma-tion of fat and muscle tissue and may program metabolic adaptations, increasing the likelihood that insulin resistance, type 2 diabetes, high blood pressure, and obesity will de-velop later in life. The chances that these disorders will occur increase with higher maternal levels of glucose and triglycer-ides during pregnancy.58,59
Effects of high maternal levels of glucose and trig-lycerides are particularly striking in the Pima Indians of Arizona. Fetal exposure to poorly controlled maternal diabetes incurs a tenfold increase in the risk that children will develop type 2 diabetes. Offspring of diabetic Pima
source: F. Hytten and G. Chamberlain, eds., Clinical Physiology in Obstetrics, Blackwell, 1980. Reprinted by permission. Also based on data from Coultart, et al. Reprinted by permission.
250
30 50 70 90 110 130 150 170 190 210 230
0 10 20 30 40 50 60 70 80 90 100110120 Mother
Fetus
Minutes After Glucose Injection
Glucose (mg/100ml)
Illustration 5.2 Concentrations of fetal blood glucose following an intravenous dose of glucose to the mother.
Table 5.7 Adverse outcomes associated with gestational diabetes62
Mother
Cesarean delivery to prevent shoulder dystocia
•
Increased risk for preeclampsia during pregnancy
•
Increased risk of type 2 diabetes, hypertension,
•
and obesity later in life
Increased risk for gestational diabetes in a
•
subsequent pregnancy Offspring
Stillbirth
•
Spontaneous abortion
•
Congenital anomalies
•
Macrosomia (
• .10 lb or .4500g)
Neonatal hypoglycemia, death
•
Increased risk of insulin resistance, type 2 diabetes,
•
high blood pressure, and obesity later in life
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Normal prepregnancy weight and weight gain
●
during pregnancy
No history of glucose intolerance
●
No prior poor obstetrical outcomes
● 62
Women with gestational diabetes may notice an creased level of thirst (especially in the morning), an in-creased volume of urine, and other signs related to high blood glucose levels.66 Urinary glucose cannot be used to diagnose nor monitor gestational diabetes, because the re-sults do not correspond to blood glucose levels.67
Treatment of Gestational Diabetes
A team approach to caring for women with diabetes in pregnancy is advised. Such teams often consist of an ob-stetrician, a registered dietitian who is also a certified dia-betes educator, a nurse educator, and an endocrinologist.
The main stay of treatment is medical nutrition therapy that begins with attempts to normalize blood glucose lev-els with diet and exercise.65
Management of blood glucose concentrations with diet and exercise is considered successful when fasting blood glucose values remain at 95 mg/dL or less, or when 1-hour postprandial values are 140 mg/dL or less and 2-hour postprandial levels are 120 mg/dL or less. Insulin is recom-mended when fasting glucose levels or when 1- and 2-hour postprandial glucose values exceed these cut-points. 65
Medical nutrition therapy has been shown to ef-fectively normalize blood glucose levels and to decrease the risk of adverse perinatal outcomes.68 Results shown in Table 5.9 demonstrate the effect and the usefulness of identifying and intervening upon women with gestational diabetes. It can also be noted from the results that a higher proportion of large newborns occurs even with medical nutrition therapy, but that the incidence is substantially less than in women with untreated gestational diabetes.
Blood glucose levels can be brought down by low caloric intakes. However, accelerated rates of starva-tion metabolism during pregnancy, as well as potentially glucose level is high, or $130 mg/dL (7.2 mmol/L).65 (You
can convert mg/dL to millimoles per liter, or mmol/L, by multiplying mg/dL by 0.05551.)
The oral glucose tolerance test (OGTT) is the basis for the diagnosis of most cases of gestational diabetes. It can be bypassed among women with very high glucose screening results and treatment started. A 100-gram glu-cose 3-hour test is used for the OGTT. A diagnosis of ges-tational diabetes is made when two or more values for venous serum or plasma glucose concentrations exceed these levels:
Overnight fast 95 mg/dL
One hour after glucose load 180 mg/dL Two hours after glucose load 155 mg/dL Three hours after glucose load 140 mg/dL65 Because of their increased risk for preeclampsia, women with gestational diabetes should be closely monitored for preeclampsia.62
A plasma glucose screening between 24 and 28 weeks of pregnancy is recommended for women at “average risk” and for high-risk women not determined by glucose screen to have elevated glucose levels earlier. Average risk is defined as women who fit neither the low- nor the high-risk profile.
Glucose screens are not recommended for women at low risk, defined as:
Age <25 years
●
Member of a low-risk ethnic group (those other
●
than Hispanic, African American, South or East Asian, Pacific Islander, Native American, or indig-enous Australian)
No diabetes in first-degree relatives
●
Table 5.8 Risk factors for gestational diabetes61,63,64 Obesity, especially high levels of central body fat
•
Weight gain between pregnancies
•
Underweight
•
Age over 35 years
•
Native American, Hispanic, African American, South
•
or East Asian, Pacific Islander, indigenous Australian ancestry
Family history of gestational diabetes
•
History of delivery of a macrosomic newborn
•
(.4500 g or .10 lb) Chronic hypertension
•
Mother was SGA at birth
•
History of gestational diabetes in a previous
•
pregnancy
Diabetes in pregnant women’s mothers during the
•
pregnancy with them and LGA at birth Low fiber intake, high-glycemic-load diets
•
Table 5.9 Comparison of outcomes of unrecognized and diet-treated gestational diabetes
Gestational Diabetes
Outcome Unrecognized Diet-Treated Controls LGA (.90th
percentile)
44% 9% 5%
Macrosomia (.4500 g)
44% 15% 8%
Shoulder dystocia
25% 3% 3%
Birth trauma 25% 0% 0%
source: Data from Adams, 1998.67
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Exercise Benefits and Recommendations
Insulin resistance is decreased and blood glucose con-trol enhanced by regular aerobic exercise such as walk-ing, joggwalk-ing, bikwalk-ing, golfwalk-ing, hikwalk-ing, swimmwalk-ing, and moderate weight lifting. This appears to be the case as well in women with gestational diabetes. Weight lifting with the arms 3 days a week for 20 minutes per session for 6 weeks, and exercising on a recumbent bicycle at 50% VO2 max for 45 minutes three times a week, have been found to normalize blood glucose levels in some women.71
Levels of exercise that approximate 50–60% of VO2 max, or maximal oxygen uptake, are most often recom-mended for women with gestational diabetes. These levels are estimated in practice using a formula for heart rates associated with various levels of VO2 max. The formula is 220 2 age 3 0.50 (for 50% of VO2 max) 5 heartbeats per minute. In the case of a 29-year-old, the estimated heart rate at 50% of VO2 max would be 220 2 29 3 0.50, or 96 beats per minute. This would be the maximum heart rate she should experience while exercising. Levels of exercise should make women become slightly sweaty but not over-heated, dehydrated, or exhausted.71
deleterious effects of resulting ketonemia on fetal devel-opment, exclude this approach to blood glucose control.65 Correspondingly, restriction of pregnancy weight gain to below recommended amounts is not advised.71 Aggressive treatment of gestational diabetes that excessively limits caloric intake and weight gain increases the risk of SGA newborns.75 On the other hand, excessively high caloric balances and weight gains are of concern because they in-crease the risk of macrosomia.69
Type 2 diabetes in nonpregnant individuals is often treated with sulfonylurea oral medications. These drugs can-not be used in pregnancy because they cross the placenta and stimulate fetal insulin production. Other types of oral medi-cations such as glyburide and metformin are being tested for use among women with gestational diabetes.70 Oral agents that reduce blood glucose levels are not yet recommended for use in pregnancy due to the lack of randomized, control-led clinical trials that demonstrate their safety.65
Presentation of a Case Study
No two women with gestational diabetes share the same his-tory, risks, needs, and response to treatment. Case Study 5.2 represents an individual’s experience with the disorder.
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