Management of women with one abnormal oral glucose tolerance test value reduces adverse outcome in pregnancy

In this study we sought to test the hypothesis that treatment of women with one abnormal oral glucose tolerance test value will result in reduction of adverse outcome. One hundred twenty-six women with one abnormal oral glucose tolerance test value and 146 women in the control group (normal oral glucose tolerance test values) participated in a prospective study during the third trimester of pregnancy. The subjects with one abnormal test result were randomized into treated (group 1) and untreated groups (group II). Group 1 subjects were treated with a strict diabetic protocol to maintain tight glycemic control by means of diet and insulin therapy. Group 2 subjects tested their capillary blood glucose for a baseline period. The study revealed that the level of glycemic control was similar before initiation of therapy (mean capillary blood glucose 118 +/- 14 vs. 119 +/- 15 mg/dl, p = NS) for groups 1 and 2, respectively. There was a significant difference in mean capillary blood glucose (95 +/- 10 vs. 119 +/- 15 mg/dl, p less than 0.0001), preprandial, and postprandial determinations between the treated and untreated groups. The overall incidence of neonatal metabolic complications (4% vs. 14%, p less than 0.05) and large infants (6% vs. 24%, p less than 0.03) was significantly lower in the treated group. Comparison between the control (normal oral glucose tolerance test) and the untreated groups showed a significantly higher incidence of large infants and metabolic complications. No difference was found between the normal and treated groups. Thus we conclude that treatment of individuals with one abnormal oral glucose tolerance test value will result in significant reduction in adverse outcome in pregnancy.     

Randomized trial of diet versus diet plus cardiovascular conditioning on glucose levels in gestational diabetes

We studied the impact of a training program on glucose tolerance in gestational diabetes mellitus. Women with gestational diabetes mellitus (N = 19) were randomized into either group I, a 6-week diet alone group (24 to 30 kcal/kg/24 hours; 20% protein, 40% carbohydrate, 40% fat), or group II, which followed the same diet plus exercise (20 minutes three times a week for 6 weeks). An arm ergometer was used to maintain heart rate in the training range. Glycemic response was monitored by glycosylated hemoglobin, a 50 gm oral glucose challenge with a fasting and 1-hour plasma glucose, and blood glucose self-monitoring, fasting and 1 hour after meals. Week 1 glycemic parameters were the same for both groups. Week 6 data (mean +/- SD) were as follows: group I glycosylated hemoglobin, 4.7% + 0.2% versus group II, 4.2% +/- 0.2%; p less than 0.001. The group I glucose challenge fasting value was 87.6 +/- 6.2 versus 70.1 +/- 6.6 mg/dl, p less than 0.001 for group II. The group I 1-hour plasma glucose challenge result was 187.5 +/- 12.9 mg/dl versus 105.9 +/- 18.9 mg/dl for group II, p less than 0.001. The glycemic levels diverged between the groups at week 4. We conclude that arm ergometer training is feasible in women with gestational diabetes mellitus and results in lower glycosylated hemoglobin, fasting, and 1-hour plasma glucose concentrations than diet alone. Arm ergometer training may provide a useful treatment option for women with gestational diabetes mellitus and may obviate insulin treatment.     

Glycemic control in gestational diabetes mellitus--how tight is tight enough: small for gestational age versus large for gestational age?

The relationship between optimal levels of glycemic control and perinatal outcome was assessed in a prospective study of 334 gestational diabetic women and 334 subjects matched for control of obesity, race, and parity. All women with gestational diabetes mellitus were instructed in the use of a memory-based reflectance meter. They were treated with the same metabolic goal according to a predetermined protocol. Three groups were identified on the basis of mean blood glucose level throughout pregnancy (low, less than or equal to 86 mg/dl; mid, 87 to 104 mg/dl; and high, greater than or equal to 105 mg/dl). The low group had a significantly higher incidence of small-for-gestational-age infants (20%). In contrast, the incidence of large-for-gestational-age infants was 21-fold higher in the mean blood glucose category than in the low mean blood glucose category (24% vs. 1.4%, p less than 0.0001). An overall incidence of 11% small-for-gestational-age and 12% large-for-gestational-age infants was calculated for the control group. A significantly higher incidence of small-for-gestational-age infants (20% vs. 11%, p less than 0.001) was found between the control and the low category. In the high mean blood glucose category an approximate twofold increase was found in the incidence of large-for-gestational-age infants when compared with the control group (p less than 0.03). No significant difference was found between the control and mean blood glucose categories (87 to 104 mg/dl). Our data suggest that a relationship exists between level of glycemic control and neonatal weight. This information is helpful in targeting the level of glycemic control while optimizing pregnancy outcome in gestational diabetes comparable to the general population.     

The relationship between large-for-gestational-age infants and glycemic control in women with gestational diabetes

In this prospective study 246 women with gestational diabetes were followed up to determine the characteristics of metabolic control associated with large-for-gestational-age infants. Memory-based reflectance meters were used for self-monitoring blood glucose. Ambulatory glucose profiles were produced to characterize glycemic control levels throughout pregnancy. With these novel approaches to the collection and representation of glucose data, the severity of glucose intolerance (hyperglycemia) was found to be associated with both maternal and neonatal morbidity in terms of infant size and cesarean section rate. By use of hierarchical cluster analysis to identify three groups on the basis of control levels (low less than 87 mg/dl, mid 87 to 105 mg/dl, high greater than 105 mg/dl) we were able to show a positive outcome in the low group with reduced rates of large-for-gestational-age (2%) and macrosomatic (0%) infants. Furthermore, we showed that as mean blood glucose levels and instability in glycemic control increased from group to group, incidence of large-for-gestational-age and macrosomatic infants increased. Whereas obesity increased the relative risk of adverse neonatal outcome, type of treatment (insulin versus diet) did not appear to be significant. Appropriately monitored toward stability within a narrow range to achieve tight metabolic control, ambulatory glycemia in pregnancy is associated with a decreased risk of maternal and fetal complications.     

Capillary blood glucose screening for gestational diabetes: a preliminary investigation

Home glucose monitoring with the use of reflectance meters is an important adjunct in the care of pregnant women with insulin-dependent diabetes. The accuracy of reflectance meters for the assay of capillary glucose specimens has been well documented. The present preliminary study was undertaken to determine the utility of outpatient screening for gestational diabetes mellitus with the use of a reflectance meter (Accu-Chek, Boehringer Mannheim Co.). One hundred twenty-five patients in our high-risk practice had a standard 50 gm glucose load at 26 to 28 weeks' gestation. Capillary glucose values were measured on site with the Accu-Chek. Venous plasma glucose levels were measured by the central laboratory chemistry analyzer. While the laboratory (x) and meter (y) glucose determinations between the two sets of values were highly correlated (R = 0.89, p less than 0.001), there was a significant difference in their average values (x = 111.74, y = 136.35, p less than 0.0001). With the use of a receiver operator characteristic curve, a meter value of 160 mg/dl was determined as the optimal threshold for performing a 3-hour glucose tolerance test. The sensitivity and specificity with the use of a meter value of 160 mg/dl were 93% and 96%, respectively, for detecting an abnormal screening test in venous plasma (greater than or equal to 135 mg/dl). A total of 32 glucose tolerance tests were performed, with four patients included who had venous values less than 135 mg/dl. All eight patients with gestational diabetes mellitus were correctly identified. These data suggest that a glucose reflectance meter can be used for accurate outpatient screening of gestational diabetes mellitus. The potential advantages of capillary blood glucose screening include both cost and efficiency. Patients with abnormal screening values can be promptly identified and scheduled for a follow-up 3-hour glucose tolerance test.     

Chronic oral terbutaline tocolytic therapy is associated with maternal glucose intolerance

Plasma glucose determinations were performed 1 hour after a 50 gm oral glucose load in 30 patients receiving long-term terbutaline therapy (20 to 40 mg/day for at least 1 week) and 247 normal control patients. A total of 63% of patients receiving terbutaline had an abnormal 1-hour value (greater than or equal to 140 mg/dl), an incidence much higher than that of control subjects (17.8%) (p less than 0.0001) for a relative risk of 3.54 (95% confidence intervals of 2.29 to 5.42). Mean 1-hour values were 112.1 mg/dl for control subjects and 149.8 mg/dl in the terbutaline group (p less than 0.0001). All abnormal values were followed by a 3-hour 100 gm oral glucose tolerance test. A total of 15.9% of the glucose tolerance tests performed in the control group (2.8% overall) were abnormal as opposed to 52.6% (33.1% overall) in patients receiving terbutaline (p less than 0.01). Nine patients were studied before and after terbutaline therapy. Results obtained during administration of terbutaline were significantly higher (102.2 mg/dl before therapy versus 145.2 mg/dl during therapy). We conclude that treatment with oral terbutaline appears to be associated with impairment of glucose tolerance in pregnancy.     

Appraisal of "rigid" blood glucose control during pregnancy in the overtly diabetic woman

The degree of maternal glucose control achieved during the third trimester of pregnancy was evaluated for 120 overtly diabetic women hospitalized on a high-risk pregnancy ward. "Rigid" blood glucose control, defined as a mean preprandial plasma glucose concentration less than 115 mg/dl was achieved in only 14% of these women. Although mean preprandial plasmal glucose concentrations ranged between 115 and 172 mg/dl in 66% of women and exceeded 172 mg/dl in 20%, the perinatal salvage rate was greater than 95%. Pregnancies of those women whose mean plasma glucose levels exceeded 172 mg/dl required earlier intervention for signs of fetal jeopardy, but the degree of glucose control was not significantly related to either perinatal death or neonatal morbidity. These results suggest that maternal hyperglycemia exceeding a mean preprandial glucose concentration of 172 mg/dl is to be avoided, whereas, at the other extreme, mean glucose levels less than 115 mg/dl or "rigid" control is unnecessary for a successful perinatal outcome.     

Serum copper and zinc levels in patients with cervical cancer

The serum copper (SCL) and zinc (SZL) levels were measured in 99 patients with cervical cancer and 50 patients with uterine myoma as controls. The mean SCL in the control group was 109.4 +/- 17.4 micrograms/ml as compared to 117.1 +/- 14.6 micrograms/dl and was not significant (NS) in 17 carcinoma in situ (CIS) patients, 142.3 +/- 14.2 micrograms/dl in 30 stage I patients (p less than 0.001), 159.0 +/- 16.6 micrograms/dl in 22 stage II patients (p less than 0.001), 171.6 +/- 25.7 micrograms/dl in 10 stage III or IV patients (p less than 0.001), and 166.2 +/- 32.2 micrograms/dl in 20 recurrent patients (p less than 0.001). The SCL returned to control level 2 weeks after surgical treatment for the stage I and II patients (mean 110.6 +/- 19.6 and 108.7 +/- 20.4 micrograms/dl, respectively, p less than 0.001). The SZL was 97.2 +/- 15.8 micrograms/dl in control patients and only showed a significant decrease in stage III or IV and recurrent patients (67.2 +/- 16.6 and 70.4 +/- 17.2 micrograms/dl, respectively). Concerning the copper/zinc ratio, the control group was 1.13 +/- 0.07 as compared to 1.17 +/- 0.07 in CIS (p = 0.06), 1.51 +/- 0.24 in stage I (p less than 0.001), 1.85 +/- 0.37 in stage II (p less than 0.001), 2.66 +/- 0.61 in stage III or IV (p less than 0.001), and 2.50 +/- 0.75 in recurrent patients (p less than 0.001). Taking mean +/- 2.5 SD of the control values as cut off points, the percentages of the recurrent patients with abnormal SCL, SZL, and a Cu/Zn ratio were 65, 30 and 90%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effect of prenatal administration of dexamethasone and ritodrine on cord blood cortisol and glucose concentrations in premature infants with respiratory distress syndrome.

The influence of maternal dexamethasone and ritodrine administration during pregnancy on cord blood cortisol and capillary serum glucose concentrations and on the incidence of respiratory distress syndrome (RDS) was studied in 30 premature infants (gestational age 27-36 weeks), and compared with a matched control group of 37 premature infants where no such medications were administered. RDS occurred less often in the treated group of infants (13.3%) than in the controls (35.1%, p < 0.01). The healthy treated infants had a significantly lower mean umbilical cord plasma cortisol concentration (5.5 +/- 1.8 ug/dl, mean +/- SD) than that observed in the controls (11.2 +/- 3.9 ug/dl, p < 0.01). Mean cord plasma cortisol concentrations increased with duration of pregnancy. No significant difference in the capillary serum glucose at 30 minutes post-delivery was found between the healthy, RDS, treated and non-treated infants. No adverse effects of steroid and ritodrine therapy were observed.     

Maternal insulin to lower the risk of fetal macrosomia in diabetic pregnancy

Fetal macrosomia is a well-recognized adverse outcome associated with gestational diabetes. Weekly measurement of fasting and postprandial glucose should identify those with fasting (greater than or equal to 100 or 105 mg/dl) or postprandial (greater than or equal to 120 mg/dl 2 hours after a meal) hyperglycemia who are at increased risk for perinatal mortality. If the prevention of macrosomia is desired, the use of prophylactic insulin, initiated as early as possible, but at the latest before 36 weeks' gestation, without regard to glycemia is effective. Alternatively, glucose self-monitoring (four to six times daily with institution of insulin treatment when fasting glucose exceeds some arbitrary threshold such as 90 mg/dl or postprandial values exceed a threshold such as 100 mg/dl) is likely to be equally effective with fewer patients requiring insulin injections.     

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.     

Amniotic fluid glucose and intraamniotic infection

Thirty-nine patients with either premature labor and/or preterm premature ruptured membranes underwent transabdominal amniocentesis to enable the following amniotic fluid analyses to be performed: culture and sensitivity, Gram's stain, and glucose determination. All nine patients with intraamniotic infection had amniotic fluid glucose values less than 10 mg/dl. Three patients with amniotic fluid glucose levels less than 10 mg/dl but without chorioamnionitis were delivered of infants within 72 hours of admission. The mean amniotic fluid glucose level of patients with intraamniotic infection (5 +/- 2.4 mg/dl) was significantly lower than in those without intraamniotic infection (39.8 +/- 18.42 mg/dl). All patients with amniotic fluid glucose values less than 10 mg/dl had either bacteria and/or white blood cells on Gram's stain. Two patients without chorioamnionitis had white cells on Gram's stain and amniotic fluid glucose values greater than 10 mg/dl. It appears that amniotic fluid glucose is more sensitive and more specific than Gram's stain in the diagnosis of intraamniotic infection. All 12 patients with low amniotic fluid glucose values were delivered of infants within 72 hours as the result of either the presence of infection or the progression of labor.     

Continuous subcutaneous insulin infusion (CSII) in pregnant diabetic patients

The efficacy of the insulin infusion pump (CSII) in pregnancy was examined in 12 diabetic patients and compared with intermittent insulin therapy (IIT). In patients poorly controlled on IIT constant and rapid equilibrium was achieved with CSII (mean of glucose levels: CSII versus IIT = 84 versus 137 mg/dl; S.D. = 36 versus 63 mg/dl; mean amplitude of glycemic excursion (MAGE) = 65 versus 112 mg/dl. In patients well controlled on IIT, CSII led to a reduction in the variation of glucose excursions (S.D. = 29 versus 36 mg/dl; MAGE = 48 versus 76 mg/dl). CSII generally produced a reduction of 20-37 per cent of daily insulin dose (in three cases there was an increase of dose with the achievement of glycemic control). Furthermore in CSII treated-patients amniotic glucose, insulin and C-peptide concentrations were found to be in the normal range (22.1 +/- 10.1 mg/dl; 5.2 +/- 2.7 microU/ml; 1.25 +/- 0.71 ng/ml, respectively). All infants were born at or near-term, had no macrosomia or neonatal problems. It is concluded that CSII is a highly efficient way to achieve normal glucose levels in pregnancy, not only in type I, but also in type II or gestational diabetes.     

Perinatal outcome of pregnancies complicated by diabetes and by maternal daily hyperglycemia not related to diabetes. A retrospective 10-year analysis

We analyzed the perinatal outcome of 1,086 pregnancies classified according to the response to the 3-hour 100-gram glucose tolerance test and the diurnal glycemic profile into the Rudge groups corresponding to control pregnant women, class A gestational diabetic women, class A/B to FRH pregnant women and women with daily hyperglycemia. Despite treatment, the diabetic pregnant women and those with daily hyperglycemia presented higher mean blood glucose levels compared to controls (76.6+/-10.2 mg/dl). The pregnancies complicated by diabetes and by daily hyperglycemia were characterized by a high incidence of prematurity, macrosomia, large for gestational age newborn infants, malformation and fetal and neonatal death, with consequent perinatal mortality. The perinatal mortality of women with daily hyperglycemia was 10 times higher than that of the controls and was similar to that of the diabetic patients. These adverse perinatal results emphasize the need for the diagnosis and control of intrauterine hyperglycemia both in diabetic pregnant women and in women with an altered diurnal glycemic profile.     

Comparison of capillary Accu-Chek blood glucose values to laboratory values

With 2 to 4% of the obstetric population demonstrating glucose intolerance, many authorities advocate the routine screening of all pregnant women. Some have questioned the cost effectiveness of such an approach and have chosen to screen only those with high-risk factors, overlooking a large percentage of gestational diabetics. The purpose of this report was to determine if Accu-Chek glucometer values are sufficiently accurate to substitute for laboratory values in our medical complex. Capillary Accu-Chek glucose values and laboratory values were compared in 140 patients. Values ranged from a low of 43 to a high of 380. The mean +/- SD glucose values were 142 +/- 73 mg/dl and 142 +/- 80 mg/dl, respectively. These values are not significantly different. Using a cutoff of 140 mg/dl as abnormal, the sensitivity of the capillary Accu-Chek was 100% and the specificity was 95% compared with the venous method. A simple linear regression indicated that there was a strong correlation between the capillary Accu-Chek glucose values and the laboratory glucose values (r = 0.95, p less than or equal to 0.0001). The slope was not different from 1 (p = 0.3135), and the intercept was not different from 0 (p = 0.4943), illustrating that there was an equality in the values and that one value may be substituted for the other.     

Spontaneous abortion in patients with insulin-dependent diabetes mellitus: the effect of preconceptional diabetic control

Fifty-nine of 94 pregnant women with juvenile-onset insulin-dependent diabetes who attended a preconceptional clinic were periodically examined by a diabetologic team. Glycemic control was obtained by intensified insulin therapy and monitored by blood glucose self-monitoring. These women were compared with the 35 pregnant women who did not receive preconceptual glycemic control. The initial glucose and maternal hemoglobin A1 values of the latter group experiencing spontaneous abortions were significantly higher (p less than 0.001) when compared with women receiving preconceptional diabetologic counseling whose pregnancies continued beyond 22 weeks' gestation. The frequency of spontaneous abortions among patients not seen before pregnancy was significantly higher (p less than 0.001), in contrast to attending women, whose rate represented the normal rate in the general population. We confirm the evidence accumulated in the recent literature that poor metabolic control around conception and in the early weeks of pregnancy may be the determining factor favoring abortion.     

Intrapartum application of the continuous glucose monitoring system in pregnancies complicated with diabetes: A review and feasibility study

Intrapartum maternal normoglycemia seems to play an important role in the prevention of adverse perinatal, maternal and neonatal outcomes. Several glucose monitoring protocols have been developed, aiming to achieve a tight glucose monitoring and control. Depending on the type of diabetes and the optimal or suboptimal glycemic control, the treatment options include fasting status of the parturient, frequent monitoring of capillary blood glucose, intravenous dextrose infusion and subcutaneous or intravenous use of insulin. Continuous glucose monitoring system (CGMS) is a relatively new technology that measures interstitial glucose at very short time intervals over a specific period of time. The resulting profile provides a more comprehensive measure of glycemic excursions than intermittent home blood glucose monitoring. Results of studies applying the CGMS technology in patients with or without diabetes mellitus (DM) have revealed new insights in glucose metabolism. Moreover, CGMS have a potential role in the improvement of glycemic control during pregnancy and labor, which may lead to a decrease in perinatal morbidity and mortality. In conclusion, the use of CGMS, with its important technical advantages compared to the conventional way of monitoring, may lead into a more etiological intrapartum management of both the mother and her fetus/infant in pregnancies complicated with DM.     

Perinatal glucose metabolism as an indicator for stress and hypoxia during different forms of delivery

In 82 term newborns divided into three groups (spontaneous delivery, caesarean section and vacuum extraction) we investigated umbilical artery pH, artery and vein glucose levels and calculated the veno-arterial difference of glucose. The three groups showed significant differences of artery and vein glucose levels. The highest umbilical artery (UA) and umbilical vein (UV) glucose levels were found after vacuum extractions (n = 13, UA: 98 mg/dl, UV: 104 mg/dl), the lowest levels were present in the group of caesarean section (n = 16, UA: 52 mg/dl, UV: 65 mg/dl). After spontaneous deliveries the intermediate levels were observed (n = 55, UA: 70 mg/dl, UV: 84 mg/dl). The mean of UA-UV-glucose difference was low after vacuum extractions and statistically different from the values after caesarean section and spontaneous deliveries. The mean of UA-pH did not show statistically significant differences in the three groups. The regression analysis between UA-pH and UA-UV-glucose difference revealed a highly significant dependency in the group of caesarean section (p less than 0.01) but no dependency after vacuum extraction. Significant dependency was also found in the group of spontaneous delivery (p less than 0.05).     

The Diabetes in Early Pregnancy Study: changes in cholesterol, triglycerides, body weight, and blood pressure. The National Institute of Child Health and Human Development--the Diabetes in Early Pregnancy Study.

This study examined changes in cholesterol, triglycerides, body weight, and blood pressure during pregnancy in 312 diabetic and 356 control women recruited within 21 days after conception. Cholesterol values rose in both groups but were significantly lower in diabetic women at each time point (166 vs 178 mg/dl at week 12, p = 0.0004). Triglyceride values also rose in both groups. Triglyceride levels did not differ between groups up to week 8 of gestation, but by weeks 10 to 12 they were significantly lower in diabetic women than in controls (75 vs 89 mg/dl at week 12, p = 0.0004). Although they were no heavier at entry, diabetic women gained significantly more weight between weeks 6 and 8 (p less than 0.001), resulting in a mean difference between groups of 1 kg. Systolic blood pressure increased steadily and significantly in the diabetic but not the control women (115.8 +/- 16.2 SD vs 109.3 +/- 11.8 mm Hg, p = 0.0006 at term). Diastolic blood pressure was higher in diabetic women on entry (70.7 vs 67.3 mm Hg, p = 0.0006) and throughout gestation. Significant correlations were found in the diabetic group between maternal blood pressure and lipids and infant birth weight. These newly found differences in cholesterol and triglyceride levels, weight gain, and blood pressure between type I diabetic and control women during gestation may have long-term cardiovascular implications.     

Effect of dietary therapy on pancreatic beta cell function in noninsulin-dependent diabetes mellitus

Twenty-four noninsulin-dependent diabetics, who were newly diagnosed or had discontinued therapy for at least 10 months, were studied for the effect of dietary therapy on pancreatic beta cell function. The mean fasting plasma glucose (176 +/- 14 vs 212 +/- 16 mg/dl, p less than 0.01) and glycosylated hemoglobin (HbA1c, 8.6 +/- 0.5 vs 9.4 +/- 0.6%, p less than 0.001) decreased significantly after 1 month of dietary control, although there was no significant change in mean body weight (57.4 +/- 2.0 vs 57.7 +/- 2.0 kg, p greater than 0.5). The mean incremental serum C-peptide (delta CP) response to oral glucose stimulation (OGTT) increased (4.6 +/- 0.6 vs 3.5 +/- 0.7 ng/ml, p less than 0.01), but that to intravenous glucagon (GT) did not (2.5 +/- 0.2 vs 2.7 +/- 0.2 ng/ml, p greater than 0.1). In 12 patients whose glycemic control improved after dietary treatment, there was a good correlation between the decrement in fasting plasma glucose and the increment in delta CP response to OGTT (r = 0.66, p less than 0.05). In conclusion: after 1 month of dietary therapy in noninsulin-dependent diabetics, (1) the serum C-peptide response to OGTT, but not to GT, improved; (2) the beta cell secretion increased only in those patients with improved glycemic control; (3) there was a good correlation between glycemic control and beta cell function.