Clinical experience with a screening program for gestational diabetes

Screening for gestational diabetes mellitus: cost-utility of different screening strategies based on a woman's individual risk of disease

AIMS/HYPOTHESIS

The cost-effectiveness of eight strategies for screening for gestational diabetes (including no screening) was estimated with respect to the level of individual patient risk.

METHODS

Cost-utility analysis using a decision analytic model populated with efficacy evidence pooled from recent randomised controlled trials, from the funding perspective of the National Health Service in England and Wales. Seven screening strategies using various combinations of screening and diagnostic tests were tested in addition to no screening. The primary outcome measure was the incremental cost per quality-adjusted life-year (QALY) over a lifetime.

RESULTS

The strategy that has the greatest likelihood of being cost-effective is dependent on the risk of gestational diabetes mellitus for each individual woman. When gestational diabetes mellitus risk is <1% then the no screening/treatment strategy is cost-effective; where risk is between 1.0% and 4.2% fasting plasma glucose followed by OGTT is most likely to be cost-effective; and where risk is >4.2%, universal OGTT is most likely to be cost-effective. However, acceptability of the test alters the most cost-effective strategy.

CONCLUSIONS/INTERPRETATION

Screening for gestational diabetes can be cost-effective. The best strategy is dependent on the underlying risk of each individual and the acceptability of the tests used. The current study suggests that if a woman's individual risk of gestational diabetes could be accurately predicted, then healthcare resource allocation could be improved by providing an individualised screening strategy.

Establishing diagnosis of gestational diabetes mellitus: Impact of the hyperglycemia and adverse pregnancy outcome study

The diagnosis of gestational diabetes mellitus (GDM) remains controversial, without universal acceptance of a particular set of diagnostic criteria, and, in fact, a lack of consensus as to whether this is an entity worth diagnosis. Some of the debate derives from differences of opinion about what degree of glucose intolerance should be labeled as GDM. Therefore, it is to be expected that there are different viewpoints on how to detect and screen for GDM. It is believed that early diagnosis will result in a significant improvement in perinatal outcome in these patients. In this review, we discuss the current data concerning screening for GDM and new strategies for GDM diagnosis in light of the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study.

Cost Analysis of Different Screening Strategies for Gestational Diabetes Mellitus

OBJECTIVE

To analyze the findings of a survey in Tehran, Iran, to determine the screening method for gestational diabetes mellitus (GDM) best suited to the local population.

METHODS

In four university teaching hospitals in Tehran, 2,416 pregnant women were classified into high-, intermediate-, and low-risk groups, on the basis of criteria established by the American Diabetes Association, and then screened for GDM. A two-step approach was implemented, with use of blood glucose thresholds of 130 mg/dL and 140 mg/dL and the previously advocated diagnostic criteria of two or more abnormal results of an oral glucose tolerance test.

RESULTS

The prevalence of GDM is increasing globally, and the major determinants of screening programs for GDM are the cost-to-benefit ratio and the prevalence in the target population. The prevalence of GDM in our study sample was 4.7%. Changing from the 130 mg/dL to the 140 mg/dL blood glucose threshold decreased case-detection sensitivity by 12%, to 88%. With this approach, however, the cost of screening for GDM per pregnancy decreased from US dollars 3.80 to US dollars 3.21 (-15.5%), and the cost per detected case of GDM declined from US dollars 80.56 to US dollars 77.44 (-3.9%).

CONCLUSION

We recommend universal screening for GDM in populations, such as ours, that have a substantial baseline prevalence of GDM and variable health-care coverage. In such a setting, a considerable proportion of cases of GDM may be missed. Moreover, universal screening is less expensive in developing countries than in more developed economies and leads to clearer long-term savings for a health service stretched to the limit.

Early diagnosis of gestational diabetes mellitus and prevention of diabetes-related complications

OBJECTIVE

[corrected] To test the hypothesis that an early diagnosis of gestational diabetes mellitus (GDM) could avoid some diabetes-related complications.

STUDY DESIGN

We compared the rates of pregnancy complications commonly related to diabetes between 189 (later screening group) and 235 (earlier screening group) women with GDM diagnosed before and after adding an universal glucose tolerance screening performed in the first antenatal visit to the traditional screening performed at 24-28 weeks of gestation.

RESULTS

Women in the later screening group were likely to have hydramnios (12.7 versus 2.1%, P<0.0001) and preterm deliveries (11.8 versus 5.5%; P=0.03). All cases of preterm premature rupture of membranes and fetal anomalies took place in the later screening group (P=0.03, P=0.007, respectively). Statistical analysis was performed using the Student's t-test, Mann-Whitney's U-test, Fisher's exact test and chi2-test. Statistical significance was set at 95% level (P<0.05).

CONCLUSIONS

Early glucose tolerance screening could avoid some diabetes-related complications in women with gestational diabetes. However, further studies are needed to know if it should be done in all pregnant women or only in those with a high risk of developing diabetes.

Cost-effectiveness analysis of gestational diabetes mellitus screening in France

OBJECTIVE

To compare three strategies for gestational diabetes screening (i) screening of high-risk pregnant women with the 50 g oral glucose tolerance test (OGTT); (ii) screening of all pregnant women with the 50 g OGTT; (iii) screening of all pregnant women according to the 75 g OGTT.

STUDY DESIGN

Cost-effectiveness analysis. The outcome measures, i.e. macrosomia, prematurity, perinatal mortality, hypertensive disorders rates were estimated from published studies and the costs from a prospective study involving 120 pregnant women.

RESULTS

Compared to the first strategy, the cost to obtain one unit of additional effectiveness with the second screening strategy, was up to 1.1 times more expensive, and with the third strategy was up to 3.7 times more expensive.

CONCLUSION

The costs per case prevented reflect a favourable cost-effectiveness ratio (CER) for screening of high-risk pregnant women by 50 g oral glucose test.

To screen or not to screen for gestational diabetes mellitus. The clinical quagmire

Although there continues to be a lack of agreement about the most appropriate way to screen for GDM, screening remains the standard of care in this country. Universal screening of all pregnant women maximizes sensitivity but has significant financial implications because of its increased costs. Additional studies are needed that apply cost-analysis to various screening protocols to identify cost-effective screening strategies.

Gestational diabetes mellitus diagnosed during early pregnancy

OBJECTIVE

This study was undertaken to compare pregnancy complications, obstetric outcomes, and perinatal outcomes between women with early-onset and late-onset gestational diabetes mellitus.

STUDY DESIGN

Fifty-gram oral glucose challenge screening was conducted among 3986 pregnant women at the time of their first antenatal visit. Women without abnormal results underwent another test at 24 to 28 weeks' gestation. Patients with gestational diabetes mellitus in early pregnancy were compared with those who had a normal glucose tolerance at the time of this first test but in whom diabetes subsequently developed.

RESULTS

Women with early-onset gestational diabetes mellitus (n = 65) were likely to be hypertensive (18.46% vs 5.88%; P =.006) and had higher glycemic values and need for insulin therapy (33.85% vs 7.06%, P =.0000) than those in whom diabetes developed later (n = 170). All the cases of neonatal hypoglycemia (n = 4) and all perinatal deaths (n = 3) were within this group (P =.005 and P =.01, respectively).

CONCLUSIONS

Women with an early diagnosis of gestational diabetes represent a high-risk subgroup.

Screening and testing for gestational diabetes mellitus

Gestational diabetes mellitus is defined as carbohydrate intolerance of variable severity first diagnosed during pregnancy. Although universal screening for gestational diabetes mellitus is practiced by more than 75% of obstetricians in the United States, agreement is lacking worldwide regarding the appropriateness of this approach. This article discusses the assumption that some type of screening program is desirable and considers how best to conduct screening and diagnostic testing for gestational diabetes mellitus.

Gestational diabetes: does the presence of risk factors influence perinatal outcome?

OBJECTIVE

Our purpose was to determine whether gestational diabetics with risk factors for gestational diabetes have worse glucose tolerance and poorer birth outcomes than those without risk factors.

STUDY DESIGN

We conducted a nonconcurrent cohort study of gestational diabetics identified by universal screening and delivered from Jan. 1, 1990, to Dec. 31, 1992. Multiple gestations and patients with chronic medical conditions were excluded. The following risk factors for gestational diabetes mellitus were abstracted: obesity (> 80 kg), family history of diabetes, previous gestational diabetes mellitus, and previous macrosomic, stillborn, or anomalous fetus. Patients with one or more risk factors were compared with those without risk factors. A group of low-risk nondiabetic patients served as controls. The incidences of A2 diabetes mellitus, cesarean section, neonatal macrosomia, and shoulder dystocia were the outcome variables of interest.

RESULTS

Selective screening would have failed to detect 43% of gestational diabetics. Twenty-eight percent of the missed gestational diabetics would have required insulin (class A2). When compared with controls, patients with gestational diabetes mellitus were at increased risk for macrosomia (26% vs 11%, p < 0.01), cesarean section (37% vs 15%, p < 0.01), and shoulder dystocia (9% vs 2%, p < 0.05). Patients with and without risk factors did not differ in mean maternal age, gestational age at delivery, birth weight, incidence of requiring insulin, macrosomia, or cesarean delivery. The similarities between those with and without risk factors remained after stratification by maternal age (> or = 30 years).

CONCLUSION

Gestational diabetics are at increased risk for adverse birth outcomes compared with low-risk controls. Class A2 diabetes mellitus and fetal macrosomia with its attendant risks are equally prevalent among patients with and without risk factors for gestational diabetes mellitus. Because > 40% of cases will be missed with selective screening, universal screening should be favored for detection of gestational diabetes mellitus.

Predictive value of 1 hour 50 g oral glucose load screening test for gestational diabetes mellitus compared to 3 hour oral glucose tolerance test in high risk pregnant women

A prospective study for detecting gestational diabetes mellitus was undertaken to evaluate the use of one hour plasma glucose level after 50 g glucose loading test (1-hr GLT) as compared to the traditional 3-hours 100 g oral glucose tolerance test (3-hr OGTT) in 396 high risk cases. Each patient, had 1-hr GLT and 3-hr OGTT performed in a separate week. Forty-two cases (10.6%) who had abnormal 3-hr OGTT were classified as gestational diabetes (GDM). One hundred and sixty cases (40.4%) had an abnormal 1-hr GLT (plasma glucose level > or = 140 mg/dl). Thirty-six of these 160 cases (22.5%) had an abnormal 3-hr OGTT. In 236 women (59.6%) that had normal 1-hr GLT (plasma glucose level < 140 mg/dl) only 6 cases (2.5%) had an abnormal 3-hr OGTT. If 1-hr plasma glucose level > or = 150 mg/dl was used as the cutoff point, 110 cases (27.8%) were found to have abnormal 1-hr GLT, and 35 of these 110 cases (31.8%) had an abnormal 3-hr OGTT. Seven of 286 women (2.4%) that had normal 1-hr GLT (plasma glucose level < 150 mg/dl) had an abnormal 3-hr OGTT. The sensitivity and specificity of the 1-hr GLT when abnormal 3-hr OGTT was used as gold standard for detecting GDM were 85.7% and 65% respectively (BS > or = 140 mg/dl). Whereas the sensitivity and specificity were 83.3% and 78.8% respectively when plasma glucose level > 150 mg/dl was used as the cut point.(ABSTRACT TRUNCATED AT 250 WORDS)

Screening and diagnosis of gestational diabetes

This chapter discusses the evidence for the existence of an entity called 'gestational diabetes', suggesting that it can be understood in terms of risk to the pregnancy and/or risk to the mother. Various diagnostic criteria used in various parts of the world are described, and a rationale for using pregnancy-specific criteria is put forth. Universal screening approaches are also characterized. Barriers to the universal adoption of a single screening scheme and set of diagnostic criteria are outlined.

High infectious morbidity in pregnant women with insulin-dependent diabetes: an understated complication

Patients with insulin-dependent diabetes are prone to infection, possibly related to poor metabolic control. Relative immune deficiency exists in pregnancy. We hypothesized that pregnant patients with insulin-dependent diabetes are at an increased risk for infection and that infection is related to poor glycemic control. We matched 65 pregnant women with insulin-dependent diabetes to 65 nondiabetic pregnant controls. At least one episode of infection before delivery occurred in 83% of the women with insulin-dependent diabetes (26% in control group). The rate of postpartum infection was five times higher in the group with insulin-dependent diabetes and they were susceptible to more kinds of infections. Although there was no overall difference among the indices of glycemic control, hemoglobin A1 obtained before the infection was higher than during infection. We conclude that a high rate of infection exists in pregnant women with diabetes; infection and poor glycemic control may be associated, but it is unclear whether improvement in metabolic control will reduce this high infection rate.

Biphasic intrauterine growth in insulin-dependent diabetic pregnancies

Early fetal growth delay (7-14 weeks of gestation) has been reported in insulin-dependent diabetic (IDD) pregnancies and in several animal models. Macrosomia is a classic feature of the infant of the IDD mother. We hypothesized therefore that a biphasic pattern of fetal growth exists in IDD pregnancies. We compared fetal growth measurements [biparietal diameter (BPD) and abdominal circumference (AC)] obtained sonographically from 106 IDD pregnancies (Class B-RT) to similar data obtained from 117 normal, nondiabetic patients. The goals for diabetic glycemic control were: fasting blood sugar less than or equal to 100 mg/dl and postprandial blood sugar less than 140 mg/dl. From one to five ultrasonographic measurements were performed at varying gestational ages in all study patients. For data analysis, one examination from each pregnancy was randomly selected by computer. Gestational age (GA) was calculated from last menstrual period and corroborated by infant physical examination (Ballard score) at birth. BPD growth pattern was biphasic in the diabetic group, described by a cubic equation: BPD = 4.99 - 0.567GA + 0.037(GA)2 - 0.0005(GA)3, R2 = 0.935. Such a biphasic pattern did not exist in the control population [BPD = -3.0323 + 0.473(gestation) - (-0.0040)(gestation)2, R2 = 0.9173]. Early growth delay was greater in fetuses that subsequently developed macrosomia (p less than 0.01). Similar results were found for AC measurements. We conclude that fetal growth delay occurs in the first half of the IDD pregnancy, followed by a phase of increased growth. The mechanism of the early growth delay is unclear. We speculate that early growth delay may be due to a "toxic" effect of glucose or other metabolite; and subsequent increased growth relates to fetal hyperinsulinism which develops from weeks 15 to 20 of gestation.

Postpartum testing for antecedent gestational diabetes

Gestational diabetes is a predictor of glucose intolerance in subsequent pregnancies and in the nongravid state. Many pregnant women are not tested for gestational diabetes, although they or their offspring may show signs suggestive of antecedent hyperglycemia. We examined the diagnostic utility of a postpartum (within 48 hours), 100 gm, oral glucose tolerance test and cord plasma glucose, cord plasma C-peptide, and 2-hour neonatal plasma glucose tests to detect antecedent gestational diabetes in women with documented gestational diabetes (n = 37) or with normal glucose tolerance test results late in the third trimester (n = 28). The 1-hour, 2-hour, and incremental 1-hour + 2-hour [( 1-hour - fasting] + [2-hour - fasting]) [2-hour - fasting]) glucose values of the postpartum glucose tolerance test showed significant differences between study participants with and without gestational diabetes (164 +/- 30 versus 115 +/- 22, 145 +/- 31 versus 101 +/- 21, and 153 +/- 51 versus 67 +/- 33 mg/dl, respectively, p less than 0.025). Maternal fasting and 3-hour postpartum glucose tolerance test glucose, cord plasma glucose, cord plasma C-peptide, and 2-hour neonatal plasma glucose values showed no significant between-group differences. Receiver operating characteristic curve analyses for these tests indicated that the incremental 1-hour + 2-hour postpartum glucose tolerance test glucose values best sustain test specificity at the low test threshold values necessary for high test sensitivity. A threshold of 110 mg/dl for this test yielded a predicted specificity of 90% and sensitivity of 80% with regard to antecedent gestational diabetes.

Is random plasma glucose an efficient screening test for abnormal glucose tolerance in pregnancy?

Random plasma glucose was determined in 276 apparently healthy pregnant women attending our antenatal clinic at 28 to 32 weeks gestation. Mean and standard deviation values within 2 h and greater than 2 h after a meal were calculated. A standard 75-g oral glucose tolerance test was then given to 250 of the 276 pregnant women. Three patients were found to be diabetic and 46 had post-load concentrations indicative of impaired glucose tolerance according to the criteria of the World Health Organization (1980). Using a cut-off point whereby 15% of the population would be tested, we would have identified only 2 of the 3 diabetics and 12 of the 46 with impaired glucose tolerance. This poor predictive power cannot be resolved by altering cut-off points for screening, or by altering the criteria for abnormal glucose tolerance. The basic problem is lack of a close relation between 2-h glucose tolerance value and random glucose when this has been taken greater than 120 min after a meal. In this population with a high prevalence of abnormal glucose tolerance, random plasma glucose is not an efficient screening test.

The cost of irregular antibody screening

The cost of irregular antibody screening in the third trimester exceeds +600,000.00 per perinatal death averted. This cost appears prohibitive compared with the clinical impact of the disease and costs of other screening tests.

Capillary glucose determination in the screening of gestational diabetes

Paired capillary-venous blood samples were obtained from 418 pregnant women undergoing an oral glucose challenge test (GCT) for the screening of gestational diabetes (GD). The relationship between capillary and plasma glucose concentrations was investigated in order to establish a capillary GCT threshold. Plasma glucose was assayed by the glucose oxidase method and capillary glucose using Reflocheck Glucose strips and a Reflocheck reflectance meter. During GCT the capillary values exceeded plasma glucose values by a mean difference of 10-12 mg/dl fasting and 22-24 mg/dl after 1 h. A high correlation between the glucose values of the two techniques was found, particularly for those at 1 h, with corresponding capillary determinations being 20 mg/dl above plasma values. The sensitivity, specificity and predictive value of the various capillary thresholds investigated in detecting GD corresponded substantially to the accuracy of plasma thresholds 20 mg/dl lower. The receiver operator characteristic curves of the plasma and capillary thresholds were similar in shape and the optimal cut-off point for performing a diagnostic test was set at 135 and 155 mg/dl, respectively. These cut-off values should be reconsidered in the light of the costs and perinatal outcome.

Prenatal screening for gestational diabetes throughout office hours

A group of 1666 consecutive pregnant women attending our prenatal clinic was screened for gestational diabetes (GD). Patients with risk factors (155) underwent a classical 50 g OGTT, while 1511 patients without risk factors for GD were submitted at random throughout the day to a simplified OGTT, consisting of a single blood glucose determination 1 h after the glucose ingestion. In these patients, plasma glucose 1 h after the glucose load averaged 104 +/- 1 mg/dl and exceeded 135 mg/dl in 315 patients. In the latter group, retested with a standard 50 g OGTT, 48 out of 1511 patients (3.2%) finally met the criteria for GD, while 25 patients had an abnormal OGTT in the group with risk factors. The blood glucose levels after simplified 50 g glucose load were significantly higher in the third (vs. first) trimester of pregnancy (113 +/- 1 vs. 96 +/- 1 mg/dl, p less than 0.001). A significant increase in mean glucose concentrations was also observed for those patients tested after 11 a.m. (107 +/- 1 mg/dl vs. 99 +/- 1 mg/dl prior to 11 a.m. p less than 0.001) and for the women with an ideal body weight (IBW) greater than or equal to 150% at the beginning of pregnancy (124 +/- 7 mg/dl vs. 104 +/- 1 mg/dl for less than 150% IBW, p less than 0.001). These variations in glucose tolerance, related to the time of the day, the gestational age and the body weight, are of limited amplitude and should not be considered in the determination of the cut-off point of the screening test. Glucose loading at random throughout the day is a simple and useful tool for the routine detection of unsuspected GD in pregnant patients attending prenatal clinics.

Gestational diabetes and impaired glucose tolerance of pregnancy in Riyadh

A total of 1088 pregnant women was screened for abnormalities in glucose metabolism at the initial antenatal visit; those with specific risk factors were screened again after 28 weeks gestation. In 210 (19.3%) plasma glucose measured 2 h after a 75 g glucose load was greater than or equal to 7.8 mmol/l (140 mg/dl). Follow-up glucose tolerance tests revealed an overall prevalence of abnormal tests of 10.3% (112 of 1088) according to the WHO criteria, of which 21 (1.9%) were diagnosed as gestational diabetes, and 91 (8.4%) as impaired glucose tolerance. This high prevalence was significantly related to age, parity and body mass index. Screening and diagnosis using criteria set by the WHO were found acceptable and are recommended to help resolve the international disagreement on diagnostic criteria of glucose metabolism abnormalities in pregnancy.

Gestational diabetes screening in a private, midwestern American population

This prospective investigation was undertaken to compare the value of routine versus selective diabetes screening in a group of predominantly middle-class, healthy, Caucasian pregnant women. Two thousand consecutively chosen persons were divided into two groups: those to undergo routine screening between 24 and 28 weeks' gestation and those to be tested selectively in the presence of standard risk factors. The two groups of patients were otherwise similar. The method of screening involved a 50 gm oral glucose challenge, followed by a 3-hour glucose test if necessary. The incidence of gestational onset diabetes in the selectively screened group (19/453, 4.2%) was twice that in the routinely screened group (21/1000, 2.1%). Evidence of glucose intolerance without a risk factor was found in only one case (1/1000, 0.1%) in the routinely screened group. This assessment of our clinical practice has allowed us to safely eliminate the need for diabetes screening in more than half of our private patients, which will reduce office time, patient inconvenience, and expense.

Diagnosis of gestational diabetes by capillary blood samples and a portable reflectance meter: derivation of threshold values and prospective validation

Paired capillary-venous samples were obtained from 255 women undergoing a glucose challenge test and 116 women undergoing an oral glucose tolerance test. The capillary equivalents for the venous threshold values were calculated by regression analysis. The glucose challenge test predictions of either normal or abnormal agreed in 82%. The sensitivity, specificity, and positive and negative predictive values for the capillary oral glucose tolerance test were 89%, 90%, 62%, and 98%, respectively. These capillary equivalents were then applied prospectively to 147 women undergoing a glucose challenge test and 141 women undergoing an oral glucose tolerance test. The concurrence rate of the glucose challenge test in the prospective group was 90%. The sensitivity, specificity, and positive and negative predictive values for the capillary oral glucose tolerance test were 64%, 95%, 75%, and 92%. When the venous threshold recommendations of the American Diabetes Association were used instead of those standard at our institution, these values increased to 75%, 98%, 83%, and 96%, respectively. The recommended capillary values of the American Diabetes Association were 100% sensitive but had a positive predictive value of only 20%. Based on the prospective group, the cost per case of gestational diabetes identified would decline 63% if both a capillary glucose challenge test and an oral glucose tolerance test were used and 25% if the capillary glucose challenge test and venous oral glucose tolerance test were used. Combining the data set for new regression equations, the following venous-capillary threshold sets emerged: glucose challenge test, 140 mg/dl/150 mg/dl; fasting oral glucose tolerance test, 105 mg/dl/114 mg/dl; 1 hour, 190 mg/dl/211 mg/dl; 2 hours, 165 mg/dl/183 mg/dl; 3 hours, 145 mg/dl/157 mg/dl. The sensitivity, specificity, and negative predictive values for the capillary oral glucose tolerance test with these thresholds were 80%, 97%, 80%, and 97%. In conclusion, capillary glucose testing for diabetes during pregnancy is feasible and cost-effective.

A random plasma glucose method for screening for abnormal glucose tolerance in pregnancy

A method is described for screening all pregnant women for abnormal glucose tolerance. It is based on determining random plasma glucose at 28-30 weeks gestation, having simply noted whether the woman had eaten within the preceding 2 h. If the random plasma glucose level was greater than or equal to 97.5th centile, a 75 g oral glucose tolerance test was performed. This method of screening is cheaper and slightly more efficient than screening based on conventional risk indications.

Screening for gestational diabetes: one-hour carbohydrate tolerance test performed by a virtually tasteless polymer of glucose

Although the 1-hour 50 gm blood glucose screening test is an effective way of detecting diabetes in pregnancy, the taste of available glucose drinks often creates gastrointestinal symptoms and leads to refusal of the patient to be tested. The efficacy of a virtually tasteless glucose polymer in testing carbohydrate tolerance in pregnancy was determined. Sixty-one pregnant patients undergoing screening for gestational diabetes underwent a 1-hour carbohydrate tolerance test of both glucose and a glucose polymer within 3 days of each other. Analysis of the data revealed a high degree of agreement between the results of the 1-hour carbohydrate tolerance test (kappa = 0.62, p less than 0.0001). These data suggest that glucose polymer can be used effectively in screening for gestational diabetes.

Clinical experience with one hundred seven diabetic pregnancies

Clinical experience with 45 pregnancies in women with Class A diabetes and 62 pregnancies in women with insulin-requiring diabetes is described. The perinatal mortality rates were 0, 16.1, and 9.3, respectively, among the Class A, insulin-requiring, and total diabetic populations. Diabetic mothers experienced significantly higher prevalences of cesarean section and ketoacidosis than did the overall population. There were no other significant differences in maternal complications. Diabetic mothers demonstrated high rates of abnormal estriol levels and relatively low rates of positive contraction stress tests. Positive contraction stress tests were highly correlated with abnormal outcome. Delivery occurred either at or after 37 weeks in 93% of the Class A and in 81% of the insulin-requiring women. In comparison to infants in the general population, those of diabetic mothers experienced significantly elevated rates of being large for gestational age, macrosomia, and hypoglycemia. Congenital abnormalities were significantly higher in the Class A, but not in the insulin-requiring population. Neonatal morbidity could not be related to maternal diabetic control and was only minimally related to gestational age.