Glucose threshold for macrosomia in pregnancy complicated by diabetes

Intensive glycemic control in gestational diabetes mellitus: a randomized controlled clinical feasibility trial

BACKGROUND

Overweight and obese women with gestational diabetes mellitus are at increased risk for adverse perinatal outcomes, and they are also more likely to have suboptimal glycemic control. However, there is a paucity of data evaluating whether lower glycemic targets could improve outcomes.

OBJECTIVE

To evaluate the feasibility of intensive glycemic control in overweight and obese women with gestational diabetes mellitus.

MATERIALS AND METHODS

We randomized 60 overweight or obese women with gestational diabetes mellitus, diagnosed between 12 and 32 weeks' gestation to either intensive (fasting <90 mg/dL, 1 hour postprandial <120 mg/dL) or standard (fasting <95 mg/dL, 1 ho postprandial <140 mg/dL) glycemic targets. Maternal glucose was assessed in 2 ways: blinded continuous glucose monitors, worn for 5 days at 2 time points (at 12-32 weeks and again at 32-36 weeks), and self-monitored glucose measurement 4 times per day. All women underwent standardized dietary counseling, and medical therapy was prescribed as needed to achieve glycemic control.

RESULTS

Between December 2015 and December 2017, we randomized 60 women to either intensive (n = 30) or standard (n = 30) glycemic control. Baseline characteristics including maternal age, body mass index, and gestational age at diagnosis were similar between the intensive and standard groups. Medical therapy was more common in women in the intensive group than those in the standard group (83 vs 57%, P = .02). Women in the intensive glycemic control group had lower glucose values as assessed by continuous glucose monitors at including 24-hour mean (-8.1; 95% confidence interval, -12.0 to -4.3 mg/dL; P < .0001) and 1-h postprandial (-11.8; 95% confidence interval, -19.7 to -3.9 mg/dL, P = .004) values. Hypoglycemia <60 mg/dL was uncommon and did not differ between groups.

CONCLUSION

Intensive glycemic targets can be used in overweight and obese women with minimal hypoglycemia, and this approach results in improved glycemic control when compared to standard glycemic targets. Further studies are needed to determine whether intensive glycemic targets can improve maternal and neonatal outcomes in high-risk women with gestational diabetes mellitus.

CLINICAL TRIAL IDENTIFIER

NCT02530866; clinicaltrials.gov.

Correlation Between Third Trimester Glycemic Variability in Non-Insulin-Dependent Gestational Diabetes Mellitus and Adverse Pregnancy and Fetal Outcomes

BACKGROUND

Gestational diabetes mellitus (GDM) is a pregnancy-related metabolic complication. Despite optimal glycemic control from self-monitoring blood glucose (SMBG) in non-insulin-dependent GDM, variations in pregnancy outcomes persist. Glycemic variability is believed to be a factor that causes adverse pregnancy outcomes. Continuous glucose monitoring system (CGMS) detects interstitial glucose values every 5 minutes, and glycemic variability data from CGMS during the third trimester may be a predictor of fetal birth weight and pregnancy outcomes. The aim of this study was to investigate correlation between third trimester glycemic variability in non-insulin-dependent GDM and fetal birth weight.

METHOD

This prospective study was conducted in 55 pregnant volunteers with non-insulin-dependent GDM that were recruited at 28 to 32 weeks' gestation from the outpatient clinic of the Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital during the study period of August 1 to December 31, 2016. Patients had CGMS installed for at least 72 hours and glycemic variability data were analyzed.

RESULTS

Of 55 enrolled volunteers, the data from 47 women were included in the analysis. Mean CGMS duration was 85.5 ± 12.83 hours. No statistically significant correlation was identified between glycemic variability in third trimester and birth weight percentiles, or between third trimester CGMS parameters and pregnancy outcomes in the study.

CONCLUSION

Based on these findings, third trimester glycemic variability data from CGMS are not a predictor of fetal birth weight percentile, and no significant association was found between CGMS parameters and adverse pregnancy outcomes; thus, CGMS is not necessary in non-insulin-dependent GDM.

Continuous Glucose Monitoring in Patients with Abnormal Glucose Tolerance during Pregnancy: A Case Series

Abnormal glucose tolerance during pregnancy is associated with perinatal complications. We used continuous glucose monitoring (CGM) in pregnant women with glucose intolerance to achieve better glycemic control and to evaluate the maternal glucose fluctuations. We also used CGM in women without glucose intolerance (the control cases). Furthermore, the standard deviation (SD) and mean amplitude of glycemic excursions (MAGE) were calculated for each case. For the control cases, the glucose levels were tightly controlled within a very narrow range; however, the SD and MAGE values in pregnant women with glucose intolerance were relativity high, suggesting postprandial hyperglycemia. Our results demonstrate that pregnant women with glucose intolerance exhibited greater glucose fluctuations compared with the control cases. The use of CGM may help to improve our understanding of glycemic patterns and may have beneficial effects on perinatal glycemic control, such as the detection of postprandial hyperglycemia in pregnant women.

Glycemic targets in pregnancies affected by diabetes: historical perspective and future directions

The definition of optimal glycemic control in pregnancies affected by diabetes remains enigmatic. Diabetes phenotypes are heterogeneous. Moreover, fetal macrosomia insidiously occurs even with excellent glycemic control. Current blood glucose (BG) targets (FBG ≤95, 1-h post-prandial <140, 2 h <120 mg/dL) have improved perinatal outcomes, but arguably they have not normalized. The conventional management approach has been to replicate a pattern of glycemia in normal pregnancy. Although these patterns are lower than previously appreciated, a randomized controlled trial (RCT) has never compared current vs. lower glucose targets powered on maternal/fetal outcomes. This paper provides historical context to the current targets by reviewing evidence supporting their evolution. Using lower targets (FBG <90, 1 h <122, 2 h <110, mean BG ≤95 mg/dL) may help normalize outcomes, but phenotypic differences (type 1 vs. type 2 vs. gestational diabetes) might require different glycemic goals. There remains a critical need for well-designed RCTs to confirm optimal glycemic control that minimizes both small for and large for gestational age across pregnancies affected by diabetes.

Diabetes in low-resourced countries

Maternal and newborn health poses one of the greatest health challenges in the developing world. Many low-income countries are now experiencing a demographic and epidemiological transition and changing of lifestyles. Thus, apparent "Western" diseases such as diabetes and obesity have been reaching the Third World countries. There is a paucity of reliable data on diabetes in pregnancy in many low-income countries. Adequate information about maternal and perinatal mortality and morbidity as a consequence of diabetes in pregnancy is scarce. This chapter presents evidence of the magnitude and impact of diabetes in pregnancy. Additionally, we discuss interventions in screening and managing diabetes in pregnancy in these specific patient populations.

A standard approach to continuous glucose monitor data in pregnancy for the study of fetal growth and infant outcomes

The power of continuous glucose monitoring system (CGMS) technology to profile glycemic patterns throughout a 24-h period has benefited the care of individuals with diabetes mellitus for over 10 years. Recently, this technology has been utilized to better understand glucose patterns in pregnancy, especially as they relate to abnormal fetal growth given that adiposity at birth is associated with increased risks for childhood obesity and metabolic syndrome. However, the lack of a standardized approach to defining glucose measures associated with maternal outcomes and fetal growth has greatly limited comparison and pooling of CGMS data among pregnancy trials, hindering our ability to take advantage of the enormous amount of data available to explore these relationships. The purpose of this article is to offer a methodical approach to the identification and extraction of CGMS-derived glucose variables for the characterization of glycemic profiles in pregnant women, particularly focusing on women with gestational diabetes or obesity who are at risk for abnormal fetal growth. A review of the properties of CGMS data and examples of how CGMS data in pregnancy have been reported to date are included. We further define several pregnancy-relevant, CGMS-derived glucose variables and directly apply them to unpublished data to illustrate how these measures might be utilized. This approach offers one possible standardized method to define and analyze these time-sensitive glucose measures to facilitate comparisons among studies and to increase our understanding of how glycemic profiles contribute to excess infant adiposity in pregnant women with and without diabetes.

The effect of race/ethnicity on adverse perinatal outcomes among patients with gestational diabetes mellitus

OBJECTIVE

The purpose of this study was to determine racial/ethnic differences in perinatal outcomes among women with gestational diabetes mellitus.

STUDY DESIGN

We conducted a retrospective cohort study of 32,193 singleton births among women with gestational diabetes mellitus in California from 2006, using Vital Statistics Birth and Death Certificate and Patient Discharge Data. Data were divided by race/ethnicity: white, black, Hispanic, or Asian. Multivariable logistic regression was used to analyze associations between race/ethnicity and adverse outcomes that were controlled for potential confounders. Outcomes included primary cesarean delivery, preeclampsia, neonatal hypoglycemia, preterm delivery, macrosomia, fetal anomaly, and respiratory distress syndrome.

RESULTS

Compared with women in other races, black women had higher odds of preeclampsia (adjusted odds ratio [aOR], 1.57; 95% confidence interval [CI], 1.47-1.95), neonatal hypoglycemia (aOR, 1.79; 95% CI, 1.07-3.00), and preterm delivery <37 weeks' gestation (aOR, 1.56; 95% CI, 1.33-1.83). Asian women had the lowest odds of primary cesarean delivery (aOR, 0.75; 95% CI, 0.69-0.82), large-for-gestational-age infants (aOR, 0.40; 95% CI, 0.33-0.48), and neonatal respiratory distress syndrome (aOR, 0.54; 95% CI, 0.40-0.73).

CONCLUSION

Perinatal outcomes among women with gestational diabetes mellitus differ by race/ethnicity and may be attributed to inherent sociocultural differences that may impact glycemic control, the development of chronic comorbidities, genetic variability, and variation in access to prenatal care, and quantity and quality of prenatal care.

The association between body mass index and gestational diabetes mellitus varies by race/ethnicity

We examined body mass index (BMI) as a screening tool for gestational diabetes (GDM) and its sensitivity among different racial/ethnic groups. In a retrospective cohort study of 24,324 pregnant women at University of California, San Francisco, BMI was explored as a screening tool for GDM and was stratified by race/ethnicity. Sensitivity and specificity were examined using chi-square test and receiver-operator characteristic curves. BMI of ≥25.0 kg/m (2) as a screening threshold identified GDM in >76% of African-Americans, 58% of Latinas, and 46% of Caucasians, but only 25% of Asians ( P < 0.001). Controlling for confounders and comparing to a BMI of ≤25, African-Americans had the greatest increased risk of GDM (adjusted odds ratio [AOR] 5.1, 95% confidence interval [CI]: 3.0 to 8.5), followed by Caucasians (AOR 3.6, 95% CI: 2.7 to 4.8), Latinas (AOR 2.7, 95% CI: 1.9 to 3.8), and Asians (AOR 2.3, 95% CI: 1.8 to 3.0). BMI's screening characteristics to predict GDM varied by race/ethnicity. BMI can be used to counsel regarding the risk of developing GDM, but alone it is not a good screening tool.

Fetal growth and well-being

Accurate monitoring of fetal growth is one of the most critically important components of prenatal care. Whether too large or too small for gestational age, the ramifications of abnormal fetal growth have both short-term and long-term sequelae for early neonatal life and beyond. Although not perfectly accurate, ultrasound and other monitoring technologies have markedly improved the ability to follow abnormalities of fetal growth and to decide if early intervention or early delivery is necessary. Clearly, perinatal morbidity and mortality are decreased with close surveillance of these at-risk fetuses.

The effect of carbohydrate intolerance on neonatal birth weight in pregnant women without gestational diabetes mellitus

BACKGROUND

There is still no consensus on screening, threshold levels and treatment of gestational diabetes mellitus. Furthermore, the importance of a positive 50-g glucose screening test in patients who had a negative 100-g oral glucose tolerance test remains controversial. We investigated the impact of the 50-g glucose screening test results on neonatal outcome in pregnant women with uncomplicated pregnancies, who had no risk factors according to ACOG criteria.

PATIENTS AND METHODS

Three hundred eighty-six pregnant women with singleton pregnancies were prospectively screened with 50-g glucose challenge test between 24 and 28 weeks. If the test result was >140 mg/dl, a 100-g 3-hour oral glucose tolerance test was performed. Patients with a positive screening test, but not diagnosed as gestational diabetes mellitus constituted the study group, and patients with a negative screening test constituted the control group. Cesarean rates, neonatal birth weights and complications were compared between these groups.

RESULTS

The cesarean delivery rates were not statistically different between the study and control groups (8.3% vs. 6.4%, P>0.05). The rates of macrosomic births were 10.0% in the study group, and 6.4% in the control group (P>0.05), but the mean birth weight (3451.67 +/- 355.70 g) in the study group was significantly higher than the mean birth weight (3296.29 +/- 365.14 g) in the control group (P=0.003). Neonatal hypoglycemia and hyperbilirubinemia was also encountered more often in babies of pregnant women with a positive 50-g glucose challenge test but negative 100-g glucose tolerance test.

CONCLUSION

Because of similarities with gestational diabetes mellitus on the basis of perinatal outcomes, the non-diabetic pregnant women with 50-g glucose screen test result over 140 mg/dl but a negative 100-g OGTT should be followed closely.

Preprandial versus postprandial blood glucose monitoring in type 1 diabetic pregnancy: a randomized controlled clinical trial

OBJECTIVE

This study was undertaken to compare preprandial and postprandial capillary glucose monitoring in pregnant women with type 1 diabetes.

STUDY DESIGN

Sixty-one women with type 1 diabetes were randomly assigned at 16 weeks' gestation to preprandial or postprandial blood glucose monitoring using memory-based glucose reflectance meters throughout pregnancy. Serial measurements of hemoglobin A1c and fructosamine were obtained throughout pregnancy. Insulin, glucose, and insulin-like growth factor-I (IGF-I) were measured in cord blood at delivery. Neonatal anthropometric measures were performed within 72 hours of delivery

RESULTS

Maternal age, parity, age of onset of diabetes, number of prior miscarriages, smoking status, social class, weight gain in pregnancy, and compliance with therapy were similar in the two groups. The postprandial monitoring group had a significantly reduced incidence of preeclampsia (3% vs 21%, P<.048), a greater success in achieving glycemic control targets (55% vs 30%, P<.001) and a smaller neonatal triceps skinfold thickness (4.5+/-0.9 vs 5.1+/-1.3, P=.05).

CONCLUSION

Postprandial capillary blood glucose monitoring in type 1 diabetic pregnancy may significantly reduce the incidence of preeclampsia and neonatal triceps skinfold thickness compared with preprandial monitoring.

A spectrum of glucose thresholds may effectively prevent complications in the pregnant diabetic patient

This article outlines the probable positive relationship between levels of maternal glycemia and perinatal morbidity and mortality. A spectrum of different glucose thresholds can be established and used appropriately to prevent each complication. This article also outlines the concept of normality and what definitions of normality should be used to evaluate the relationship between the level of glycemia and perinatal outcome. Definitive conclusions are hampered by a lack of uniformity in definitions and interventions, and by a failure in some analyses to control for confounding variables. However, it is suggested that different levels of glycemia are required to prevent different diabetic complications. Thus, although it is not always possible to achieve targeted levels of glycemic control in all patients, any improvement will be beneficial because it will affect fetal complications associated with that glucose threshold.

Diabetes complicating pregnancy

Despite the well-documented relationship between morbidity in pregnancy and pregestational maternal diabetes, the corrected perinatal outcome is, in most series, equal to or better than that of the general reference obstetric population. No single aspect or element of contemporary management is responsible for this improvement; rather, a combination of interventions seems responsible. Targeting delivery early in term, improved compliance, better glycemic control during pregnancy, improved control at conception, improved neonatal care, family planning, and early screening for fetal abnormalities all likely contribute to improved outcome. The currently observed rates of perinatal mortality suggest that an irreducible minimum mortality rate may be reached; however, large disparities in access to care and treatment continue to result in a wide range in rates of morbidity and mortality, a fact that pertains to outcomes in general as well as to pregnancies complicated by diabetes. The identification of women with lesser degrees of hyperglycemia as diabetic by lowering the thresholds for glucose tolerance test abnormality suggests an importance of the diagnosis that is not supported by evidence of either related morbidity or therapeutic benefit. The extrapolation of risk to women with lesser degrees of hyperglycemia seems to have little basis, and the management of women with mild glucose intolerance as if they had overt diabetes is unwarranted. The excess of resources dedicated to the identification and monitoring of an increasing number of women with mild abnormalities of glucose metabolism should prompt a reevaluation of these practices. Perinatal benefits of this expenditure are difficult to document or nonexistent, and there is a predictable increase in iatrogenic morbidities associated with the diagnosis. The exception in the most recent recommendations is the addition of a random glucose measure to screen for the rare women with overt undiagnosed diabetes who presents for prenatal care, because these women are at increased risk of morbidities related to diabetes. A curious statement was made in the summary and recommendations of the fourth International Congress on Gestational Diabetes: "There remains a compelling need to develop diagnostic criteria for GDM [gestational diabetes mellitus] that are based on the specific relationships between hyperglycemia and risk of adverse outcome." If these relationships are undefined, what is the import of the diagnosis? At the author's center, application of the new diagnostic thresholds for the diagnosis of gestational diabetes mellitus has increased the incidence to over 6%. Without a clear expectation of benefit, this increase represents an unsupportable investment of resources. What are the prospects for improving understanding of the relationships between glucose intolerance and pregnancy risks? The direction of new guidelines and recommendations seems to be moving away from resolution of the relationships. The new criteria result in the diagnosis of gestational diabetes in an increasing number of women who were previously normal. It is easier to differentiate women at an extreme of hyperglycemia from normal. Investigations will be even less able to identify attributable effects of glucose intolerance in pregnancy with the inclusion of women with lesser degrees of hyperglycemia. As evidenced in O'Sullivan's original series, women with fasting hyperglycemia in pregnancy are still presumed to be at increased risk of fetal death. This risk factor remains important in clinical management if insulin treatment, fetal surveillance, and early term delivery can reduce the risk of fetal loss. At the author's center, the relationships among outpatient measures of fasting glycemia, glucose tolerance testing results, and perinatal outcomes are evaluated. Preliminary results suggest that fasting glycemia measured at the time of a 50-g glucose tolerance test is significantly correlated with and as sensitive and predictive of morbidity as the glucose tolerance test diagnosis of gestational diabetes. If these results are confirmed, it will be difficult to rationalize continued glucose tolerance testing.

Factors associated with fetal macrosomia in offspring of gestational diabetic women

OBJECTIVE

To determine whether there is a relationship between birthweight and interval between 1-h and 3-h glucose tolerance test (GTT) as well as other factors.

METHODS

We performed a retrospective analysis of our computerized diabetes database for the years 1992-1997. Ninety-four women with gestational diabetes fulfilled the inclusion criteria (i.e., singleton gestation, term delivery, absence of medical conditions, and known interval between 1-h and 3-h GTT). They were evaluated based on prepregnancy body mass index (BMI), mean glucose values, interval between diagnostic testing, and gestational age of 3-h GTT.

RESULTS

Subjects with GDM had a mean glucose value of 96.8 mg/dl and average prepregnancy BMI of 29.3 kg/m2. When GDM subjects with and without macrosomic infants were compared, mean glucose values (97.4 vs. 96.6 mg/dl) and mean interval (18.1 vs. 17.0 days) between diagnostic testing did not significantly differ. However, maternal prepregnancy BMI was higher in the group of women who gave birth to macrosomic infants (32.2 vs. 28.22 kg/m2, P = 0.008). Using stepwise multiple regression, maternal prepregnancy BMI was the only variable found to be predictive of macrosomia.

CONCLUSION

We were unable to show a statistical relationship between interval of diagnostic testing and rate of macrosomia. However, we demonstrated a clear relationship between maternal BMI and infant birthweight.

Level of glycemia and perinatal outcome in pregestational diabetes

This article provides the reader with relevant information regarding the association between level of glycemia and perinatal outcome in preexisting diabetes. Although the glycemic profile is a continuum in nature, different thresholds of glucose are associated with fetal complications such as stillbirth, spontaneous abortion, congenital anomalies, fetal macrosomia, and metabolic and respiratory complications. For each complication, a different targeted threshold of normality is required. Thus, although it is not always possible to achieve optimal glycemic control in all patients, any improvement will be beneficial because it will reduce the rate of complications for a given glucose threshold.

Fetal growth in diabetic pregnancy

In summary, fetal macrosomia occurs in almost one third of diabetic pregnancies regardless of class. Abnormal fetal fat stores lead to difficult labor, dystocia, and birth injury as well as postnatal metabolic transition. The abnormal body fat distribution at birth may destine some of these infants to lifelong obesity. Abnormal fetal growth in diabetic pregnancy appears to occur with any elevations in maternal glucose levels, however modest. Detection of macrosomia is therefore a major goal of diabetic pregnancy management.

Common clinical manifestations of maternal diabetes in newborn infants: implications for the practicing pediatrician

Even though perinatal mortality of infants of diabetic mothers has decreased remarkably in recent years and now approaches that of the general population, these infants still face a multitude of potential complications and the propensity for increased morbidity, both in utero and postnatally. Many of these complications are clearly related to the metabolic status of the diabetic mother. Increasing awareness among insulin-dependent diabetic patients and health providers of the need for glycemic control and the ever-growing understanding of the peculiarities of diabetic pregnancies eventually should combine to provide the best possible outcome for these infants.

Growth promoting peptides in diabetic and non-diabetic pregnancy: interactions with trophoblastic receptors and serum carrier proteins

Infantile macrosomia in diabetic pregnancy (DP) is commonly attributed to fetal hyperinsulinism. However, insulin-like growth factors in the mother and the fetus, their binding proteins and their placental receptors may also play roles in the process of fetal overgrowth. We measured levels of maternal and cord serum IGF-I, IGF-II, C-peptide, IGFBP-1, IGFBP-2 and IGFBP-3 in 8 White Class B insulin dependent DP and 8 non-diabetic pregnancies (NP). These results were correlated with the concentration and affinity of placental trophoblastic membrane receptors (TR) for insulin (IN), IGF-I and IGF-II as well as with infant and placenta weights and maternal body mass indices. Significant respective differences between the diabetic and non-diabetic groups were found in mean infant weight, 4248 +/- 114 vs 3555 +/- 119 g (p < 0.001), placental weight 765 +/- 51 vs 575 +/- 24 g (p < 0.01), maternal body mass index 32.8 +/- 3.8 vs 21.3 +/- 1.2 (p < 0.02), cord serum IGF-I 136.8 +/- 6.6 vs 85.9 +/- 5.7 ng/ml (p < 0.01), cord serum C-peptide 18.7 +/- 3.5 vs 9.0 +/- 1.7 ng/ml (p < 0.025), cord serum IGFBP-1 21.9 +/- 4.7 vs 133.2 +/- 43.2 ng/ml (p < 0.025), cord serum IGFBP-2 672.0 +/- 76 vs 1206 +/- 220 ng/ml (p < 0.05) and cord serum IGFBP-3 11.5 +/- 1.0 vs 5.6 +/- 0.6 ng/ml (p < 0.001). No significant differences were found between DP and NP with respect to cord serum IGF-II, maternal serum IGF-I, IGF-II, C-peptide, IGFBP-1, IGFBP-2 and IGFBP-3, and the concentration and affinity of TR for IN, IGF-I and IGF-II. Analysis of variance revealed an interaction between infant weight and the weight of the placenta (p < 0.01), cord IGF-I (p < 0.02), cord C-peptide (p < 0.01) and cord IGFBP-3 (p < 0.01). Regression analysis revealed significant correlations of cord IGF-I with cord values of IGFBP-2 (r = -0.52, p = 0.04) and IGFBP-3 (r = 0.66, p < 0.005). Maternal serum IGF-I significantly correlated only with maternal IGFBP-3 (r = 0.65, p < 0.01). These results suggest that increased fetal production of insulin and IGF-I may contribute to the development of infantile macrosomia in DP. Concomitant changes in fetal production of IGFBPs, particularly IGFBP-2 and IGFBP-3, may modulate the action of insulin and IGFs. The lack of change in number or binding affinity of placental trophoblastic receptors for insulin, IGF-I and IGF-II tends to exclude a significant regulatory role of these receptors in the production of fetal macrosomia.

Postprandial versus preprandial blood glucose monitoring in women with gestational diabetes mellitus requiring insulin therapy

BACKGROUND

The fetuses of women with gestational diabetes mellitus are at risk for macrosomia and its attendant complications. The best method of achieving euglycemia in these women and reducing morbidity in their infants is not known. We compared the efficacy of postprandial and preprandial monitoring in achieving glycemic control in women with gestational diabetes.

METHODS

We studied 66 women with gestational diabetes mellitus who required insulin therapy at 30 weeks of gestation or earlier. The women were randomly assigned to have their diabetes managed according to the results of preprandial monitoring or postprandial monitoring (one hour after meals) of blood glucose concentrations. Both groups were also monitored with fasting blood glucose measurements. The goal of insulin therapy was a preprandial value of 60 to 105 mg per deciliter (3.3 to 5.9 mmol per liter) or a postprandial value of less than 140 mg per deciliter (7.8 mmol per liter). Obstetrical data and information on neonatal outcomes were collected.

RESULTS

The prepregnancy weight, weight gain during pregnancy, gestational age at the diagnosis of diabetes and at delivery, degree of compliance with therapy, and degree of achievement of target blood glucose concentrations were similar in the two groups. The mean (+/- SD) change in the glycosylated hemoglobin value was greater in the group in which postprandial measurements were used (-3.0 +/- 2.2 percent vs. 0.6 +/- 1.6 percent, P < 0.001) and the infants' birth weight was lower (3469 +/- 668 vs. 3848 +/- 434 g, P = 0.01). Similarly, the infants born to the women in the postprandial-monitoring group had a lower rate of neonatal hypoglycemia (3 percent vs. 21 percent, P = 0.05), were less often large for gestational age (12 percent vs. 42 percent, P = 0.01) and were less often delivered by cesarean section because of cephalopelvic disproportion (12 percent vs. 36 percent, P = 0.04) than those in the preprandial-monitoring group.

CONCLUSIONS

Adjustment of insulin therapy in women with gestational diabetes according to the results of postprandial, rather than preprandial, blood glucose values improves glycemic control and decreases the risk of neonatal hypoglycemia, macrosomia, and cesarean delivery.

Impact of increasing carbohydrate intolerance on maternal-fetal outcomes in 3637 women without gestational diabetes. The Toronto Tri-Hospital Gestational Diabetes Project

OBJECTIVE

Our purpose was to assess maternal-fetal outcomes in patients with increasing carbohydrate intolerance not meeting the current criteria for the diagnosis of gestational diabetes.

STUDY DESIGN

We conducted a prospective analytic cohort study in which nondiabetic women aged > or = 24 years, receiving prenatal care in three Toronto teaching hospitals, were eligible for enrollment. A glucose challenge test and an oral glucose tolerance test were administered at 26 and 28 weeks' gestation, respectively; risk factors for unfavorable maternal-fetal outcomes were recorded. Caregivers and patients were blinded to glucose values except when test results met the current criteria for gestational diabetes.

RESULTS

Of 4274 patients screened, 3836 (90%) continued to the diagnostic oral glucose tolerance test. The study cohort was formed by the 3637 (95%) patients without gestational diabetes, carrying singleton fetuses. Increasing carbohydrate intolerance in women without overt gestational diabetes was associated with a significantly increased incidence of cesarean sections, preeclampsia, macrosomia, and need for phototherapy, as well as an increased length of maternal and neonatal hospital stay. Multivariate analysis showed that increasing carbohydrate intolerance is an independent predictor for various unfavorable outcomes.

CONCLUSION

Increasing maternal carbohydrate intolerance in pregnant women without gestational diabetes is associated with a graded increase in adverse maternal-fetal outcomes.

Overexpression of GLUT3 placental glucose transporter in diabetic rats

The localization of the two major placental glucose transporter isoforms, GLUT1 and GLUT3 was studied in 20-d pregnant rats. Immunocytochemical studies revealed that GLUT1 protein is expressed ubiquitously in the junctional zone (maternal side) and the labyrinthine zone (fetal side) of the placenta. In contrast, expression of GLUT3 protein is restricted to the labyrinthine zone, specialized in nutrient transfer. After 19-d maternal insulinopenic diabetes (streptozotocin), placental GLUT3 mRNA and protein levels were increased four-to-fivefold compared to nondiabetic rats, whereas GLUT1 mRNA and protein levels remained unmodified. Placental 2-deoxyglucose uptake and glycogen concentration were also increased fivefold in diabetic rats. These data suggest that GLUT3 plays a major role in placental glucose uptake and metabolism. The role of hyperglycemia in the regulation of GLUT3 expression was assessed by lowering the glycemia of diabetic pregnant rats. After a 5-d phlorizin infusion to pregnant diabetic rats, placental GLUT3 mRNA and protein levels returned to levels similar to those observed in nondiabetic rats. Furthermore, a short-term hyperglycemia (12 h), achieved by performing hyperglycemic clamps induced a fourfold increase in placental GLUT3 mRNA and protein with no concomitant change in GLUT1 expression. This study provides the first evidence that placental GLUT3 mRNA and protein expression can be stimulated in vivo under hyperglycemic conditions. Thus, GLUT3 transporter isoform appears to be highly sensitive to ambient glucose levels and may play a pivotal role in the severe alterations of placental function observed in diabetic pregnancies.

Toward universal criteria for gestational diabetes: the 75-gram glucose tolerance test in pregnancy

OBJECTIVES

The purpose of this study was to determine the distribution of values for the 75 gm glucose tolerance test in pregnancy and to define glucose intolerance by the relationship between maternal glucose values and neonatal macrosomia.

STUDY DESIGN

A total 3505 unselected pregnant women were given a 75 gm, 2-hour glucose tolerance test. Diet or insulin therapy was offered only to patients with a fasting plasma glucose level > or = 105 mg/dl or a 2-hour post-glucose-load value > or = 200 mg/dl. Birth weights of live-born singletons delivered from 36 to 42 weeks whose mothers had a fasting plasma glucose level < 105 mg/dl and 2-hour post-glucose-load value < 200 mg/dl were used to calculate relationships between glucose levels and birth weights.

RESULTS

At 24 to 28 weeks' gestation the mean and SD plasma glucose values were fasting 83.6 (8.9) mg/dl, 1 hour 128.4 (32.9) mg/dl, and 2 hour 108.4 (24.8) mg/dl. In a multiple logistic regression model the factors found to be statistically significantly associated with macrosomia were maternal race, parity, prepregnancy body mass index, weight gain, gestational age at testing, fasting plasma glucose level, and 2-hour post-glucose-load value. A positive association was found between maternal glucose values and birth weight percentiles. No clinically meaningful glucose threshold values relative to birth weight or macrosomia were found.

CONCLUSION

In the absence of a meaningful threshold relationship between glucose tolerance test values and clinical outcome, criteria defining gestational diabetes will probably be established by consensus.

A survey of UK diabetic pregnancy management

The provision of care and current management strategies for diabetic pregnancy in the United Kingdom were assessed by canvassing British diabetologists. Questionnaires were sent to 376 Consultant Physicians known to have an interest in diabetes, in 239 Health Districts. The response rate was 52% providing information from 182 (76%) Districts. In 66 (36%) Districts, there was an existing combined diabetes/obstetric clinic, with median annual caseloads of 13 (range 1-200) patients. Preconception counselling was offered in 22 clinics. In 153 (84%) of the clinics, the standard WHO diagnostic criteria for diabetes were applied to pregnant patients and 149 (97%) of the clinics using WHO criteria treated patients with 'Impaired Glucose Tolerance' as if they were overtly diabetic. Reflectance meters for home monitoring were employed in 119 (65%) clinics. Target pre-meal blood glucose values were less than or equal to 6.0 (range 3.0-12.0) mmol l-1 (n = 172) and post-meal less than or equal to 8.0 (5.0-10.5) mmol l-1 (n = 139). Insulin was introduced when blood glucose values exceeded 7.0 (5.0-12.0) mmol l-1 (n = 162) pre-meal or 9.0 (5.5-15.0) mmol l-1 (n = 129) post-meal. No unit used oral hypoglycaemic agents during pregnancy. Sixty percent of respondents were unable to provide accurate fetal loss/perinatal mortality rates, usually due to lack of recorded data. Where data were available, fetal loss was almost always intra-uterine. Only 78 (43%) centres allowed pregnancy to progress to term.(ABSTRACT TRUNCATED AT 250 WORDS)

Diabetes mellitus in pregnancy. Management and outcome of diabetic pregnancies in the state of Hesse, F.R.G.; a five-year-survey

From 1982 to 1986, data of 446 pregnancies in diabetic women were compared to equivalent information on 111,390 unselected non-diabetic pregnancies with the help of the Hessische Perinatalstudie (Hessian Perinatal Study, HEPS), a computerized system of collecting information on obstetrical care in the state of Hesse, F.R.G. Patient histories, pregnancy risks, birth risks, fetal outcome and maternal well-being were evaluated to survey the current situation of diabetic pregnancies in the specific constellation of widely decentralized obstetrical management and to point out possible benefits of stronger centralization of these high-risk pregnancies. Perinatal mortality in children of diabetic mothers (4.89%) remains substantially higher than in children of non-diabetic mothers (0.63%), with two thirds of the fetal loss occurring before birth. Infant morbidity, including macrosomia, shows the same impact of maternal diabetes. Maternal post-partum morbidity is increased in diabetic women. 37.9% of children of diabetic mothers were delivered in obstetrical units equipped for maximal care, 17.5% in primary care level hospitals. Perinatal mortality and morbidity as well as maternal complications indicate that diabetic women should receive obstetrical care in those centers that can provide all the necessary facilities.

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.