Perspectives in Disease Prevention and Health Promotion Public Healt Guidelines for Enhancing Diabetes Control Through Maternal- and Child-Health Programs
These guidelines were developed by the Division of Diabetes Control, Center for Prevention Services, CDC, in collaboration with the Division of Maternal and Child Health, Bureau of Health Care Delivery and Assistance, Health Resources and Services Administration, and have been endorsed by the Association for Maternal and Child Health and Crippled Children's Programs.
This document provides guidelines for maternal- and child-health programs for an appropriate public health approach to diabetes control during pregnancy. Particular concerns for the public health-care sector include: (1) screening of women to detect gestational diabetes; (2) identification of women with established diabetes who may become pregnant; (3) ensurance of appropriate care for women with diagnosed diabetes (either established or gestational) on-site or through referral; (4) postpartum follow-up and continuing care of women with established diabetes to maintain good blood- glucose control before pregnancy and throughout subsequent pregnancies; and (5) postpartum follow-up of women with gestational diabetes to detect previously undiagnosed established diabetes, to monitor the maintenance of ideal body weight to reduce the chance of developing diabetes later in life, and to ensure prompt diagnosis of diabetes if and when it develops. Key elements are: the identification and establishment of linkages with existing programs and resources and development of the necessary referral and follow- up mechanisms.
STATEMENT OF THE PROBLEM
The presentation of a pregnant woman with established diabetes mellitus * or gestational diabetes mellitus ** (GDM) to a public health clinic is relatively rare (about 3%-4% of all pregnancies). However, the morbidity associated with pregnancies affected by diabetes may be substantial, since diabetes may result in a disproportionate number of adverse pregnancy outcomes (1). Therefore, the combination of diabetes and pregnancy presents a special challenge in the public health-care setting.
Incorporating several basic guidelines and principles into the public health sector's management of pregnancy may markedly improve pregnancy outcomes for women with either established or gestational diabetes. With appropriate care, the level of risk associated with diabetes and pregnancy can be reduced to that of the nondiabetic population.
Problems Related to Established Diabetes. While only approximately 0.3% of all U.S. pregnancies occurs among women with established diabetes, many serious clinical problems are associated with diabetes during pregnancy. The estimated 10,000-14,000 infants born annually to women with established diabetes are at high risk for mortality; prematurity; congenital defects; macrosomia; neonatal hypoglycemia; respiratory distress syndrome; and hyper- bilirubinemia, particularly when maternal glucose levels are not tightly controlled during pregnancy (1).
Risks of maternal complications are also associated with diabetes during pregnancy and include: ketoacidosis; exacerbated microvascular, renal, ocular, and neural complications; urinary-tract infections; toxemia; and hydramnios (2).
Problems Related to Gestational Diabetes. GDM occurs in about 2%-3% of pregnancies in the United States (3) and usually develops during the second or third trimester, when levels of insulin-antagonist hormones increase and insulin resistance usually occurs. Approximately 90,000 women with GDM give birth each year. GDM may go undetected in up to 50% of cases.
The effects of GDM on offspring include: macrosomia; birth trauma due to difficult delivery; shoulder dystocia; hypoglycemia; increased incidence of fetal/neonatal mortality (particularly from women with previously uniden- tified adult-onset, Type II, diabetes); hypocalcemia; and hyperbilirubinemia (4).
Women with GDM are at increased risk for developing diabetes after parturition (5). In addition, many women diagnosed as glucose-intolerant during pregnancy may be previously unidentified Type II diabetics. This risk of developing diabetes and the opportunity to identify as yet undiagnosed women with Type II diabetes are also compelling reasons for screening.
Opportunities to Improve Outcomes. The public health sector can improve pregnancy outcomes among women with established diabetes and women in whom GDM is detected by several methods, including: (1) identification (including outreach, screening, and diagnosis); (2) care/referral (including appropriate patient education and nutrition counseling, referrals to high-risk centers or to private care); (3) maternal/neonatal follow-up; and (4) professional education.
Purpose of the Guidelines. The guidelines should be adapted to the needs of each state, its health-care delivery system, and the levels of professional and fiscal resources available. The guidelines are designed to: (1) increase public and provider awareness of the problem and identify special needs related to diabetes before conception and during pregnancy; (2) propose concrete suggestions for enhancing diabetes control through maternal- and child-health programs in the public health system by improving coordination of the health-care system components, use of resources, and patient involvement in the care regimen; and (3) provide a framework for states/localities to use in adapting these guidelines to meet their specific planning, care, and training needs.
IDENTIFICATION OF WOMEN WITH DIABETES
Outreach. Prepregnancy counseling and early prenatal care by professionals knowledgeable about diabetes during pregnancy are particularly important for women with established diabetes (6). Normalization of maternal glucose levels before pregnancy and during the first 8 weeks of gestation has been effective in reducing the occurrence of congenital malformations (1). Strict control of glucose throughout pregnancy can reduce the risk of peri- natal mortality among infants of mothers with diabetes to a level seen in nondiabetic pregnant women. Therefore, prepregnancy counseling -- with the goal of attaining euglycemia before conception and maintaining it throughout gestation -- is important for women with diabetes. Prepregnancy evaluation is also important to assess maternal complications of diabetes, such as detecting the presence of retinopathy, nephropathy, hypertension, and coronary atherosclerosis.
Ideally, a woman with established diabetes is aware of the risks associated with diabetes and pregnancy and will consult a physician when contemplating pregnancy. In reality, however, most women come to public health-care settings already several weeks pregnant. Outreach efforts for women with established diabetes include:
target their efforts and to optimally use scarce public health resources.
Unlike women with established diabetes, women who develop GDM need to be identified by health-care providers. Therefore, outreach efforts related to identifying GDM should be targeted at those health-care professionals who have contact with pregnant women (e.g., nurse-midwives, nurse-practitioners, family practitioners, obstetricians, and nutritionists).
Screening and Diagnosis. Screening and diagnostic activities in the public health-care setting focus on identifying women who develop GDM. The following recommendations for GDM screening and diagnosis were formulated at the Second International Workshop-Conference on Gestational Diabetes Mellitus (7).
Many investigators have supported the view that certain risk factors may assist in identifying pregnant women prone to developing GDM. These include: age of 25 years or older; obesity; history of diabetes in a first-degree relative; history of pregnancy with stillbirth or infant over 9 pounds; and history of congenital malformation in a previous child. Although a history of hypertension is often cited as a risk factor for GDM, it does not necessarily assist in identifying a woman prone to develop GDM. However, it is a serious coexisting condition and can increase the risk of adverse outcome in women with GDM. It is now well accepted that only universal screening can completely identify all patients with GDM. However, most pregnant patients with these specific risk factors will not have GDM, since GDM occurs in only approximately 2%-3% of the population.
Therefore, it is recommended that, where possible, all pregnant women be screened for GDM (7). In public health settings, universal screening may not be possible. Therefore, if factors exist that preclude universal screening, all women 25 years of age or older and women with any of the above-mentioned risk factors (regardless of age) should be screened. These factors are not only associated with greater risk of developing GDM but are more often associated with poor perinatal outcome.
Urine testing alone is not an adequate screening test for glucose intolerance during pregnancy. Blood-glucose screening should be performed between 24 weeks' and 28 weeks' gestation. The following glucose challenge test is recommended: (1) patient is given 50 grams of a standard glucose solution to be ingested in a 10-minute period without regard to time of day or last meal; (2) patient should not eat or smoke until 1-hour blood sample is drawn; (3) blood sample is taken at 1 hour and analyzed by standard techniques available to the health department. A venous plasma-glucose result of 140 mg/dl (7.8 mmol/L) is recommended as a threshold for referral for definitively diagnosing GDM. Whole blood-glucose standards are approximately 15% less than plasma-glucose values.
Indications for screening before 24 weeks' gestation include: (1) previous GDM; (2) previous large-for-gestational-age infant; (3) polyhy- dramnios; (4) suspected large-for-gestational-age fetus; (5) glycosuria value of 1+ or greater on two or more occasions or 2+ or greater on one occasion; (6) increased thirst or urination; (7) recurrent vaginal and urinary-tract infections (e.g., monilial vulvovaginitis). These high-risk women should be screened on initial visit, or as soon as possible in the pregnancy, and again at 24 weeks' gestation (if not positive on the earlier test).
If blood-glucose meters are used for screening, the cut-off values will differ, and the sensitivity and specificity of the procedure will vary from screening using venous plasma. A lower value should be used as a screening cut-off for referral for definitive diagnosis.
Definitive diagnosis of GDM should be accomplished with a 100-gram oral glucose-tolerance test (OGTT). The test should be performed in the morning after an overnight fast of at least 8 hours but not more than 14 hours, and after at least 3 days' unrestricted diet (over 150 grams carbohydrate) and physical activity. A 100-gram oral glucose load is given in a volume of at least 400 ml fluid. Venous plasma glucose is measured fasting and at 1, 2, and 3 hours. The patient should remain seated and not smoke throughout the test. Definitive diagnosis requires that two or more of the following venous plasma-glucose concentrations be met or exceeded:
fasting: 105 mg/dl (5.8 mmol/L)
1-hour: 190 mg/dl (10.6 mmol/L) 2-hour: 165 mg/dl (9.2 mmol/L) 3-hour: 145 mg/dl (8.1 mmol/L) Capillary blood measurements, using glucose oxidase-impregnated test strips, are useful for monitoring therapy but not sufficiently accurate for diagnostic purposes. Glycosylated hemoglobin (i.e., HbA subscript-1 or HbA subscript-1C) is also not a sensitive enough diagnostic indicator for GDM.
REFERRAL TO CARE
Women with established diabetes and women who develop GDM should be considered at high risk and be referred immediately for specialized care if such care is not available on-site. This will ensure that activities, such as determination of the appropriate level of care needed by prepregnant and pregnant women with diabetes, consultation, training, referral, and follow- up, can best be coordinated within the various components of the health-care system, be it a public health setting, private medical setting, hospital, or community clinic. Optimally, a perinatal center for high-risk individuals will be available -- particularly for women with established diabetes mellitus -- that offers a multidisciplinary team consisting of an obstetrician/perinatologist, an internist/endocrinologist, a social worker, a dietitian, and a nurse/patient educator. If this level of care is unavailable, the patient should receive, at a minimum, care from a local obstetrician knowledgeable in management of diabetes during pregnancy. Patient education should be an integral part of medical care. The public health role in referrals is to identify care resources, assure access to care, follow up to ensure that care is obtained, and assure that the care obtained is appropriate.
Obtaining a plan of care from the provider to whom a referral is made is desirable for several reasons: (1) it describes the elements that will/will not be provided, which helps the public health clinic identify other resources that may be needed to fill gaps; (2) it provides information on the comprehensiveness and quality of care provided by professionals/facilities to whom patients are referred; and (3) it may be valuable for follow-up for postpartum care or subsequent pregnancies.
The public health sector should retain a role in certain aspects of patient care (such as follow-up, education, social services, transportation, home visits), even though patients may be referred for special needs. While direct care may not be provided to high-risk women in the public health-care setting, public health professionals should be aware of the elements of appropriate care to assess the quality of services provided by the profes- sionals/facilities to whom they refer.
Elements of Care for Women with Gestational Diabetes.
without patient education and self-management. Therefore, the public health clinic should ensure that patient education is an integral component of the care plan developed for each patient. All pregnant women identified with either GDM or established diabetes should receive: (1) information about the interaction of pregnancy and diabetes; (2) information on the importance and frequency of blood-glucose self-monitoring (established diabetes and gesta- tional if managed with insulin); (3) instruction on how to self-monitor blood glucose (established diabetes only, unless GDM treated with insulin) and urine testing for ketones; (4) instruction regarding use of medications; and (5) exercise instruction.
In addition, women with GDM should be instructed in the importance of postpartum weight control, including appropriate exercise, due to the increased likelihood of developing diabetes in later years. Women with established diabetes should be instructed in the importance of preconception counseling and blood-glucose normalization before conception in future pregnancies to reduce the risk of congenital anomalies from diabetes. In addition, women should be aware that pregnancy can exacerbate complications of diabetes.
The public health sector can play a major role in instructing patients about self-monitoring. Self-monitoring demonstrates the day-to-day variability in glucose levels; promotes self-discipline, control, and a heightened understanding of the condition; provides immediate feedback on hyperglycemia or hypoglycemia; and provides essential data to enable pregnant women and their health-care providers to make appropriate changes in diet, exercise, and insulin therapy.
Because urine-glucose testing is not a sufficiently reliable indicator of glucose levels, frequent blood-glucose determinations are strongly recommended throughout pregnancy for women with established diabetes or with GDM controlled with insulin. The practitioner should instruct the pregnant woman with established diabetes to test urine for ketones and to self-monitor blood glucose throughout pregnancy. Patients with established diabetes should be informed that insulin requirements may increase substantially in the second and third trimesters. The public health-care sector should ensure the availability of equipment critical to self-monitoring.
Short- and long-term follow-up are integral components of care for this high-risk population. In the short term, it is important for the public health sector to identify sources of care during pregnancy to which patients can be referred and then to make certain the referrals are completed.
For women with GDM, a repeat oral glucose-tolerance test (OGTT) is recom- mended at the first postpartum check-up. If the test is positive, the patient should be provided with or referred for treatment; if the test is negative, the patient should be advised that she is still at risk of developing diabetes later in life. She should be informed that the onset of diabetes may be delayed or prevented if she attains and maintains ideal body weight, and, if necessary, a referral for counseling on diet and/or weight control should be made. Regular follow-up and an annual OGTT are recommended.
Follow-up for the woman with established diabetes entails an adjustment of the insulin dosage after delivery (usually to the prepregnancy level), informing the mother about the importance of returning to her ideal body weight, and achieving and maintaining good blood-glucose control postpartum. In addition, it is important to provide counseling for the woman with established diabetes regarding the importance of glucose control before any subsequent pregnancies. Referral to a family planning clinic for an appro- priate contraceptive method may also be appropriate.
Successful pregnancy outcomes depend on linkages and referrals to appro- priate care and services. A list of resources that may be used for referral or that may provide educational and promotional materials is presented below. While this list is not exhaustive, it is indicative of the resources available to improve pregnancy outcomes.
American Association of Diabetes Educators American College of Obstetricians and Gynecologists American Diabetes Association Division of Diabetes Control, Center for Prevention Services, CDC Crippled Children's Programs Diabetes Research and Training Centers Family Planning Clinics Juvenile Diabetes Foundation Maternal and Child Health Programs National Diabetes Advisory Board National Diabetes Information Clearinghouse National Institute of Child Health and Human Development National Research Council State Diabetes Control Programs Women's, Infants', and Children's Nutrition Programs (WIC)
Prepared in collaboration with the Johns Hopkins University School of Public Health and a panel of expert consultants.
* Diabetes diagnosed before conception.
** Carbohydrate intolerance of variable severity with onset or first recognition during pregnancy.
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