Glucose levels and insulin secretion during a 75 g glucose challenge test in normal pregnancy

TyGIS: improved triglyceride-glucose index for the assessment of insulin sensitivity during pregnancy

Background

The triglyceride-glucose index (TyG) has been proposed as a surrogate marker of insulin resistance, which is a typical trait of pregnancy. However, very few studies analyzed TyG performance as marker of insulin resistance in pregnancy, and they were limited to insulin resistance assessment at fasting rather than in dynamic conditions, i.e., during an oral glucose tolerance test (OGTT), which allows more reliable assessment of the actual insulin sensitivity impairment. Thus, first aim of the study was exploring in pregnancy the relationships between TyG and OGTT-derived insulin sensitivity. In addition, we developed a new version of TyG, for improved performance as marker of insulin resistance in pregnancy.

Methods

At early pregnancy, a cohort of 109 women underwent assessment of maternal biometry and blood tests at fasting, for measurements of several variables (visit 1). Subsequently (26 weeks of gestation) all visit 1 analyses were repeated (visit 2), and a subgroup of women (84 selected) received a 2 h-75 g OGTT (30, 60, 90, and 120 min sampling) with measurement of blood glucose, insulin and C-peptide for reliable assessment of insulin sensitivity (PREDIM index) and insulin secretion/beta-cell function. The dataset was randomly split into 70% training set and 30% test set, and by machine learning approach we identified the optimal model, with TyG included, showing the best relationship with PREDIM. For inclusion in the model, we considered only fasting variables, in agreement with TyG definition.

Results

The relationship of TyG with PREDIM was weak. Conversely, the improved TyG, called TyGIS, (linear function of TyG, body weight, lean body mass percentage and fasting insulin) resulted much strongly related to PREDIM, in both training and test sets (R² > 0.64, p < 0.0001). Bland–Altman analysis and equivalence test confirmed the good performance of TyGIS in terms of association with PREDIM. Different further analyses confirmed TyGIS superiority over TyG.

Conclusions

We developed an improved version of TyG, as new surrogate marker of insulin sensitivity in pregnancy (TyGIS). Similarly to TyG, TyGIS relies only on fasting variables, but its performances are remarkably improved than those of TyG.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12933-022-01649-8.

Oral glucose tolerance test results in early pregnancy: A Finnish population-based cohort study

AIMS

To analyze early-pregnancy oral glucose tolerance test (OGTT) results and differences between early- and late-pregnancy OGTT results in a population-based cohort.

METHODS

From 3/2013 to 12/2016, pregnant women in South Karelia, Finland, were invited to undergo a 2-hour 75 g OGTT at 12-16 weeks' gestation (OGTT1) and, if normal, repeat testing at 24-28 weeks (OGTT2). Early and late gestational diabetes (GDM) were diagnosed using the same nationally endorsed criteria (fasting [FPG], 1- or 2-hour plasma glucose ≥5.3, ≥10.0 or ≥8.6 mmol/L, respectively).

RESULTS

In OGTT1 (n = 1401), the mean (SD) FPG, 1- and 2-hour values were 4.85 (0.34), 6.63 (1.73) and 5.60 (1.28) mmol/L, respectively. Early GDM was diagnosed in 209 (14.9%). In OGTT2 (n = 1067), late GDM was diagnosed in 114 (10.6%). In women without GDM (n = 953), the mean FPG values were higher and post-load values lower in OGTT1 vs. OGTT2. No interaction effects of gestational timepoint and maternal BMI on OGTT results were detected, except for the 2-hour value. In women with late GDM, both mean FPG and post-load values were lower in OGTT1 vs. OGTT2. Results were similar employing the IADPSG GDM criteria.

CONCLUSIONS

Our findings suggest that gestational-age specific OGTT thresholds for early GDM diagnosis need to be generated.

High Fasting Plasma Glucose during Early Pregnancy: A Review about Early Gestational Diabetes Mellitus

Fasting plasma glucose (FPG) is nowadays routinely measured during early pregnancy to detect preexisting diabetes (FPG ≥ 7 mmol/L). This screening has concomitantly led to identify early intermediate hyperglycemia, defined as FPG in the 5.1 to 6.9 mmol/L range, also early gestational diabetes mellitus (eGDM). Early FPG has been associated with poor pregnancy outcomes, but the recommendation by the IADPSG to refer women with eGDM for immediate management is more pragmatic than evidence based. Although eGDM is characterized by insulin resistance and associated with classical risk factors for type 2 diabetes and incident diabetes after delivery, it is not necessarily associated with preexisting prediabetes. FPG ≥ 5.1 mmol/L in early pregnancy is actually poorly predictive of gestational diabetes mellitus diagnosed after 24 weeks of gestation. An alternative threshold should be determined but may vary according to ethnicity, gestational age, and body mass index. Finally, observational data suggest that early management of intermediate hyperglycemia may improve prognosis, through reduced gestational weight gain and potential early introduction of hypoglycemic agents. Considering all these issues, we suggest an algorithm for the management of eGDM based on early FPG levels that would be measured in case of risk factors. Nevertheless, interventional randomized trials are still missing.

Screening for dysglycaemia during pregnancy: Proposals conciliating International Association of Diabetes and Pregnancy Study Group (IADPSG) and US National Institutes of Health (NIH) panels

The International Association of Diabetes and Pregnancy Study Group (IADPSG) has proposed that blood glucose levels for the diagnosis of gestational diabetes mellitus (GDM) be the values associated with a 1.75-fold increase in the risk of neonatal complications in the Hyperglycaemia and Adverse Pregnancy Outcomes (HAPO) study. However, this recommendation was not adopted by the US National Institutes of Health (NIH) panel as it would have been responsible for a huge increase in the prevalence of GDM with no clear evidence of a reduction of events at such blood glucose values. Considering this aspect, we now propose the use of a blood glucose threshold combination associated with an odds-ratio of 2.0 for neonatal disorders [fasting plasma glucose (FPG)≥ 95 mg/dL, or a 1-h glucose value after a 75-g oral glucose tolerance test (OGTT)≥ 191 mg/dL or a 2-h glucose value ≥ 162 mg/dL] for GDM diagnosis. This would lead to a lower prevalence of GDM and concentrate medical resources on those with the highest risk of complications. This would also allow the use of a similar FPG value for both the diagnosis and therapeutic target of GDM. The IADPSG also proposed screening for dysglycaemia during early pregnancy, using FPG measurement with a similar threshold after 24 weeks of gestation. We propose the same strategy considering an FPG value ≥ 95 mg/dL as abnormal, but only after confirmatory measurements. We also believe that an OGTT should not be used before 24 weeks of gestation as normal values during that time are as yet unknown.

Relationship between tyrosine phosphorylation and protein expression of insulin receptor and insulin resistance in gestational diabetes mellitus

The relationship between tyrosine phosphorylation (TP) and protein expression of insulin receptor (InsR) and insulin resistance (IR) in patients with gestational diabetes mellitus (GDM) was investigated. The InsR expression and TP in skeleton muscle tissue were determined by Western blotting and immunoprecipitation in women with GDM (GDM group, n=22), normal pregnant women (normal pregnancy group, n=22) and normal non-pregnant women (normal non-pregnant group, n=13). Fasting plasma glucose (FPG) and fasting insulin (FINS) were measured by oxidase assay and immunoradioassay. The results showed that the levels of FPG (5.61±0.78 mmol/L), FINS (15.42±5.13 mU/L) and Homeostasis model assessment-IR (HOMA-IR) (1.21±0.52) in GDM group were significantly higher than those in normal pregnancy group (4.43±0.46 mmol/L, 10.56±3.07 mU/L and 0.80±0.31 respectively) (P<0.01). The levels of FINS and HOMA-IR in normal pregnancy group were significantly higher than those in normal non-pregnant group (7.56±2.31 mU/L and 0.47±0.26 respectively) (P<0.01). There was no significant difference in the InsR expression level among the three groups (P>0.05). TP of InsR with insulin stimulation was significantly decreased in GDM group (0.20±0.05) as compared with normal pregnancy group (0.26±0.06) (P<0.01). TP of InsR with insulin stimulation in normal pregnancy group was lower than that in normal non-pregnant group (0.31±0.06) (P<0.01). TP of InsR with insulin stimulation was negatively related with HOMA-IR in GDM group (r=-0.525, P<0.01). There was no correlation between the protein expression of InsR and HOMA-IR in GDM group (r=-0.236, P>0.05). It was suggested that there is no significant correlation between the protein expression of InsR in skeletal muscle and IR in GDM, but changes in TP of InsR are associated with IR in GDM.

Euglycemic hyperinsulinemia increases blood pressure in pregnant rats independent of placental antiangiogenic and inflammatory factors

BACKGROUND

Although pregnancies associated with hyperinsulinemia and altered placental angiogenic and inflammatory factors are at increased risk for developing preeclampsia, the effects of euglycemic hyperinsulinemia on placental factors and blood pressure regulation during pregnancy are unclear. We hypothesized that chronic hyperinsulinemia results in increased placental soluble fms-like tyrosine kinase 1(sFlt-1) and tumor necrosis factor α (TNF- α) levels and hypertension in pregnant rats.

METHODS

On gestational day (GD) 14, Sprague-Dawley rats were assigned as normal pregnant or pregnant + insulin. Insulin was infused subcutaneously by osmotic minipump for 5 days at a dose of 1.5 mU/kg/min. Those rats receiving insulin were supplemented with 20% glucose in drinking water to maintain euglycemia. On GD 19, mean arterial pressure (MAP) and heart rate (HR) were assessed in conscious rats by indwelling carotid catheters, followed by collections of blood, placentas, and fetuses. In addition to placental sFlt-1 and TNF-α levels, circulating insulin, glucose, leptin, cholesterol, triglyceride, and free fatty acid concentrations were measured.

RESULTS

MAP was higher in pregnant + insulin vs. normal pregnant rats; however, HR was similar between groups. Although litter size and placental weight were comparable, fetuses from pregnant + insulin rats were heavier. Importantly, circulating insulin concentration was elevated in the pregnant + insulin group, with no change in glucose level. Moreover, circulating leptin, cholesterol, triglyceride, and free fatty acid concentrations were increased in the pregnant + insulin group. There were no differences in placental sFlt-1 and TNF-α concentrations between groups.

CONCLUSIONS

In summary, sustained euglycemic hyperinsulinemia, comparable with insulin levels in preeclamptic women, can raise blood pressure in pregnancy independent of recognized placental factors associated with preeclampsia.

The potential impact of new diagnostic criteria on the frequency of gestational diabetes mellitus in Sweden

The International Association of Diabetes and Pregnancy Study Groups (IADPSG) has suggested new diagnostic criteria for gestational diabetes mellitus. Many centers in Europe still use the World Health Organization (WHO) criteria. In southern Sweden we use the 2-h threshold of the European Association for the Study of Diabetes criteria based on universal screening with a 75-g oral glucose tolerance test. We have retrospectively scrutinized oral glucose tolerance tests in a subset of 174 women included in a previous study, diagnosed with gestational diabetes mellitus 1996-1999. A complete repeat oral glucose tolerance test was performed directly after diagnosis in 120 women. When applying the current Swedish criteria, and the IADPSG and the WHO criteria to the material, gestational diabetes mellitus was confirmed in 67% (80/120), 84% (101/120), and 80% (96/120), respectively. Hence, 26% (101/80) more women were identified by the IADPSG criteria and 20% (96/80) more women by the WHO criteria, compared with the criteria presently in use.

Prevalence of impaired glucose tolerance and diabetes after gestational diabetes mellitus comparing different cut-off criteria for abnormal glucose tolerance during pregnancy

OBJECTIVE

To determine the prevalence of diabetes and impaired glucose tolerance after gestational diabetes mellitus in relation to different categories of glucose tolerance during pregnancy.

DESIGN

Prospective study.

SETTING

Four delivery departments and three hospitals in southern Sweden took part in recruitment and follow-up.

POPULATION

Women undergoing a 75g oral glucose tolerance test during pregnancy delivering in 2003-2005.

METHODS

At first follow-up, one to two years after delivery, 29% of eligible women with abnormal glucose tolerance during pregnancy had an oral glucose tolerance test - 160 with gestational diabetes and 309 with gestational impaired glucose tolerance - in addition to 167 control women. Cut-off levels defining gestational diabetes and impaired glucose tolerance were two-hour capillary blood glucose levels of 9.0 and 7.8mmol/l or plasma glucose 10.0 and 8.6mmol/l, respectively.

MAIN OUTCOME MEASURES

Frequency of abnormal test results at follow-up.

RESULTS

Diabetes was diagnosed in 11% and impaired glucose tolerance in 24% of women with gestational diabetes vs. 4 and 23% in those with gestational impaired glucose tolerance, respectively. Combining women with abnormal test results during pregnancy revealed diabetes or impaired glucose tolerance in 29% as compared to 10% among controls; the odds ratio (95% confidence interval) for having abnormal test results was 3.3 (1.8-5.9) in a multivariate logistic regression analysis.

CONCLUSIONS

Lowering the cut-off level for gestational diabetes to include the category of impaired glucose tolerance would identify a high percentage of women with diabetes and impaired glucose tolerance postpartum, who constitute target groups for intervention and/or diabetes prevention.

When should screening be performed for gestational diabetes?

AIM

To consider the arguments for screening outside the standard screening period of 24 to 28 weeks of gestation.

MATERIALS AND METHODS

A search of the literature between 1990 and 2010 was performed using the PubMed® and Cochrane® databases. Recommendations from learned societies in diabetology and obstetrics & gynaecology were consulted.

RESULTS

Gestational diabetes mellitus screening is classically recommended between weeks 24 and 28 of pregnancy, the period during which glucose tolerance deteriorates. However, the increasing prevalence of type 2 diabetes in women of childbearing age with risk factors requires earlier screening. Fasting blood glucose should be measured at the fi rst visit during early pregnancy for these patients. The diagnostic threshold is the same as for patients who are not pregnant, i.e. blood glucose > 1.26 g/l. However, the benefit of screening for gestational diabetes during early pregnancy for women with risk factors has not been supported by prospective studies. Therefore oral glucose tolerance testing during early pregnancy is not currently recommended for the detection of gestational diabetes. Screening for gestational diabetes, regardless of the recommended screening policy, must be performed between weeks 24 and 28 of pregnancy. There are no reasons to consider subsequent screening for gestational diabetes at a later stage.

Glucose tolerance of premenopausal women after menopause due to surgical removal of ovaries

OBJECTIVE

To evaluate the influence of the abrupt withdrawal of ovarian function on glucose tolerance by studying premenopausal women before and after oophorectomy.

METHODS

Thirty premenopausal women who needed hysterectomy for benign reasons volunteered for the study in our hospital in Istanbul, Turkey. An oral glucose tolerance test (OGTT) was performed before surgery and 3, 6 and 12 months after surgery. Fasting glucose, fasting insulin levels and insulin/glucose indexes, HOMA indexes, insulin and glucose levels were measured during OGTT.

RESULTS

The mean fasting and 2-h glucose levels of the women did not change significantly during the 12 months of follow-up. However, the glucose levels during the glucose tolerance tests changed significantly after surgery (p<0.05). Insulin responses to the glucose tolerance test also increased significantly (p<0.005). Insulin/glucose indexes were significantly higher after surgery (p<0.005). Type 2 diabetes mellitus was detected in five women and impaired glucose tolerance was detected in 12 of the 30 patients after surgery in the 12-month period.

CONCLUSION

The impairment of carbohydrate metabolism due to an abrupt decrease in natural estrogen levels should be considered before removing the ovaries during hysterectomy in premenopausal patients.

Screening for hyperglycaemia in pregnancy: Consensus and controversy

Policy decisions on whether to implement screening programmes depend on whether the proposed programmes meet a set of criteria laid down by the World Health Organization. Screening for hyperglycaemia in pregnancy (HGP) does not meet all the criteria. However the case for screening has been strengthened by a number of recent developments, including: rising prevalence of HGP because of increasing maternal age and BMI; the results of the Hyperglycaemia and Adverse Pregnancy Outcomes study, showing that adverse effects of HGP are seen over a wider range of plasma glucose levels than previously thought; two large trials which showed the benefits of treating lesser degrees of HGP; trials showing that metformin and glibenclamide were effective and safe alternatives to immediate insulin in those without good control on lifestyle measures alone. However uncertainties remain around the threshold for treatment, and on the best screening strategy.

Maternal metabolism and obesity: modifiable determinants of pregnancy outcome

BACKGROUND

Obesity among pregnant women is highly prevalent worldwide and is associated in a linear manner with markedly increased risk of adverse outcome for mother and infant. Obesity in the mother may also independently confer risk of obesity to her child. The role of maternal metabolism in determining these outcomes and the potential for lifestyle modification are largely unknown.

METHODS

Relevant studies were identified by searching PubMed, the metaRegister of clinical trials and Google Scholar without limitations. Sensitive search strategies were combined with relevant medical subject headings and text words.

RESULTS

Maternal obesity and gestational weight gain have a significant impact on maternal metabolism and offspring development. Insulin resistance, glucose homeostasis, fat oxidation and amino acid synthesis are all disrupted by maternal obesity and contribute to adverse outcomes. Modification of lifestyle is an effective intervention strategy for improvement of maternal metabolism and the prevention of type 2 diabetes and, potentially, gestational diabetes.

CONCLUSIONS

Maternal obesity requires the development of effective interventions to improve pregnancy outcome. Strategies that incorporate a detailed understanding of the maternal metabolic environment and its consequences for the health of the mother and the growth of the child are likely to identify the best approach.

Biological factors and the determination of androgens in female subjects

The idea of the presence of androgens in females may sound peculiar as androgens generally refer to male hormones. Although produced in small amounts in women, androgens have direct and significant effects on many aspects of female physiology. Moreover, androgens are precursors to estrogens, which are the predominant female sex hormones. The measurement of androgens in blood is important in the diagnosis of both gonadal and adrenal functional disturbances, as well as monitoring subsequent treatments. The accuracy of such measurements is crucial in sports medicine and doping control. Therefore, the concentration of androgens in female subjects is frequently measured. Analysing such compounds with accuracy is especially difficult, costly and time consuming. Therefore, laboratories widely use direct radioimmunoassay kits, which are often insensitive and inaccurate. It is especially complicated to determine the level of androgens in women, as the concentration is much lower compared to the concentration found in males. Additionally, the amount of androgens in fluids tends to decrease with aging. Analyses of hormone concentrations are influenced by a myriad of factors. The factors influencing the outcome of these tests can be divided into in vivo preanalytical factors (e.g., aging, chronobiological rhythms, diet, menstrual cycle, physical exercise, etc.), in vitro preanalytical factors (e.g., specimen collection, equipment, transport, storage, etc.) and as mentioned before, analytical factors. To improve the value of these tests, the strongly influencing factors must be controlled. This can be accomplished using standardised assays and specimen collection procedures. In general, sufficient attention is not given to the preanalytical (biological) factors, especially in the measurement of androgens in females. Biological factors (non-pathological factors) that may influence the outcome of these tests in female subjects have received little attention and are the topic of the present review.

Management of gestational diabetes from the patient's perspective ? a comparison of Swedish and Middle-Eastern born women

AIM

To explore patients' evaluation of a specialized diabetes clinic for management of women with gestational diabetes born in Sweden and the Middle East and its contribution to a decreased level of stress and improved coping capability to promote health in patients receiving care.

BACKGROUND

No studies comparing patients' perceptions of healthcare in women of different origin with gestational diabetes have been found. A perceived clinical problem in specialized diabetes care is of lower activity level in self-care in foreign- than Swedish-born women and the question is whether the healthcare organization is optimal in meeting different individuals' needs.

DESIGN

Explorative study.

METHOD

Semi-structured individual interviews by external evaluators.

PARTICIPANTS

Consecutive sample. Females with gestational diabetes, 13 born in Sweden and 14 born in the Middle East.

RESULTS

The healthcare model was perceived as functioning well. Swedish women were problem focused and information seeking. Frustration and stress were increased due to perceived delay in information concerning gestational diabetes, limited access to telephone service and lack of confidence in staff because they lacked the expected competence. Control of gestational diabetes and pregnancy by different persons led to perceived lack of holistic care. Women from the Middle East felt cared, had been given the necessary information and claimed to follow advice. Adequate information reduced respondents' anxiety and increased their control over the situation.

CONCLUSIONS

The clinic needs to be further improved by adapting programmes to persons to become problem focused by giving adequate information immediately.

RELEVANCE TO CLINICAL PRACTICE

Cultural differences in coping strategies and attitudes to gestational diabetes need to be considered. Training of staff working with gestational diabetes patients is urgently needed.

Waist circumference is the key risk factor for diabetes in Korean women with history of gestational diabetes

This study investigated relationships between various obesity indices and an onset of type 2 diabetes mellitus (TY2DM) in Korean women with history of gestational diabetes mellitus (GDM). A total of 909 women with history of GDM were enrolled from the four major hospitals, and the first postpartum follow-up examination was made at 6 weeks, and annually thereafter. During postpartum follow-up period, mean 2.13+/-1.75 years, we conducted 2h 75 g OGTT and measured glucose, insulin, c-peptide, lipid profiles, lifestyle and dietary evaluation. For obesity parameters, we measured body weight, body mass index (BMI), waist and hip circumference, subcutaneous fat thickness, body fat percent and weight using bioelectrical impedance tests. Diabetes incidence for 6 years was 12.8% and all the obesity indices were significantly higher in subjects with diabetes or glucose intolerance than those with normal glucose tolerance (p<0.001). When obesity indices were compared between <25th versus >75th percentile, the waist circumference presented with the strongest relationship (odds ratio=5.8, 95% CI 2.8-11.8). This relationship persisted, OR=3.86 (95% CI 1.8-8.2), even after adjusting for the potential confounders. This prospective study revealed that waist circumference is one of the key risk factors for the onset of diabetes in Korean women with history of GDM.

Insulin resistance and sympathetic overactivity in women

Insulin sensitivity decreases for the first time in females at the time of menarche. A much more profound decrease in insulin sensitivity is observed at the end of pregnancy. This physiological insulin resistance is not accompanied by a rise in overall sympathetic activity as reflected in plasma noradrenaline levels, but there is evidence of moderate sympathetic overactivity in muscle and the heart. Pre-eclampsia is characterized by increased insulin resistance, sympathetic overactivity and a particular lipid profile. Thus it is the first manifestation of metabolic syndrome. Women with a history of pre-eclampsia have persistent insulin resistance after pregnancy associated with increased sympathetic activity of the cardiovascular system, and coronary artery disease later in life. Aging is accompanied by a greater increase in sympathetic traffic in women than in men, and inflammation (measured via C-reactive protein) seems to be more strongly related to metabolic syndrome in women than in men. The clinical relevance of these observations remains to be shown. As the key factors of metabolic syndrome, such as insulin resistance and sympathetic overactivity, are closely inter-related, treatment should be aimed at cutting the vicious circle at many points: lifestyle modification (diet, increasing exercise) as a basis of therapy, use of insulin sensitizers (e.g. metformin) to decrease insulin resistance, central sympatholytics (e.g. moxonidine), and AT-receptor blockers or angiotensin-converting enzyme (ACE) inhibitors to overcome sympathetic overactivity, hypertension and inflammation.

Effect of antiretroviral agents on carbohydrate metabolism in HIV-1 infected pregnant women

BACKGROUND

Despite the correlation between the use of protease inhibitors (PI) and adverse metabolic glycemic events, no prospective study has examined these parameters in pregnant women who use these drugs.

METHODS

A prospective study was conducted on 57 pregnant women to investigate the effect of antiretroviral drugs (ARV) on the carbohydrate metabolism during pregnancy. The women were divided into three groups: ZDV Group, 20 HIV-1 infected women taking ZDV; TT Group, 25 patients on triple antiretroviral treatment (ZDV + 3TC + NFV); and Control Group, 12 pregnant women. Blood samples were obtained during the first visit for the determination of fasting plasma glycemia, when the patients were also submitted to a 75 g oral glucose test (OGTT-75g). These procedures were performed four times along pregnancy.

RESULTS

The median values of the area under the glycemia curve (AUC) determined over a period of 120 min between the 33rd and 38th week were 11 685 mg/dL for the Control Group, 13 477 mg/dL for the ZDV Group, and 13 650 mg/dL for the TT Group (p = 0.049). There was an increase in the AUC along pregnancy for all three groups studied, regardless of the treatment used, although this increase was significant only in the TT Group (p = 0.001). The antiretroviral agents had no deleterious effects on prematurity, low birth weight, intrauterine growth restriction rates, or on Apgar score.

CONCLUSION

An association was detected between the use of PI and the development of carbohydrate intolerance during pregnancy. The antiretroviral agents had no deleterious effects on perinatal prognosis.

Testosterone levels in pregnant women correlate with the insulin response during the glucose tolerance test

OBJECTIVE

To evaluate the association between insulin/insulin-like growth factor I (IGF-I) systems and androgen levels in pregnancy.

DESIGN

Prospective cohort study.

SETTING

Yale University School of Medicine.

PATIENT(S)

Pregnant women undergoing a 100-gram 3-hour glucose tolerance test (GTT).

INTERVENTION(S)

Serum samples collected during GTT were analyzed for insulin, androgens, free IGF-I, insulin-like growth factor-binding protein (IGFBP) 1, and estriol.

MAIN OUTCOME MEASURE(S)

Observing the relationship between insulin/IGFs and androgen levels.

RESULT(S)

The insulin area under the curve (I(AUC)) during GTT correlated positively with total T and free T, but not with dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulphate (DHEAS), or estriol. The peak insulin values (I(max)) during GTT also correlated positively with total T and free T, but not with DHEA, DHEAS, or estriol. There was no statistically significant correlation of T levels with free IGF-I, IGFBP-1, glucose, DHEAS, or estriol. Multiple linear regression analysis modeling showed that I(AUC) and I(max) did have a statistically significant correlation with free T levels.

CONCLUSION(S)

This study demonstrates for the first time that I(AUC) and I(max) measured in hyperinsulinemic states such as pregnancy correlate with T levels. In view of the lack of correlation between insulin and DHEAS or estriol, insulin-related T production during pregnancy is likely of ovarian origin.

Low-dose hormone therapy and carbohydrate metabolism

OBJECTIVE

To evaluate the influence by two low doses of oral continuous-combined formulations of 17 beta-estradiol (E(2)) and norethisterone acetate (NETA) on carbohydrate metabolism in healthy postmenopausal women.

DESIGN

A double-blind, randomized, placebo-controlled trial.

SETTING

Volunteers at a university hospital.

SUBJECT

One hundred twenty healthy postmenopausal women.

INTERVENTION(S)

One hundred twenty women were randomized to three treatment arms: (1) E(2) 1 mg/NETA 0.25 mg group (n = 40); (2) E(2) 1 mg/NETA 0.5 mg group (n = 40); (3) placebo group (n = 40). A total of 102 women completed 12 months of treatment. An oral glucose tolerance test (OGTT) was performed at baseline and at 3, 6, and 12 months.

MAIN OUTCOME MEASURE(S)

Fasting glucose, fasting insulin, total area under the curve (AUC) and insulin/glucose index during OGTT.

RESULT(S)

Fasting levels of glucose and insulin declined significantly in the E(2)/NETA 0.5 mg group. At OGTT, the total AUC for insulin declined in both active arms. The curve for glucose increased significantly in the E(2)/NETA 0.25 mg group. A lower insulin/glucose index was observed during OGTT in both active regimens when compared with placebo. In the active treatment groups, a significant reduction of fasting glucose and/or fasting insulin was encountered in women with higher basal fasting levels (fasting glucose >4.2 mmol/L or log-fasting insulin >0.87).

CONCLUSION(S)

Oral low-dose E(2) 1 mg/NETA 0.5 mg regimen did not impair carbohydrate metabolism, but seemed to improve insulin sensitivity in healthy postmenopausal women.

Gestational diabetes diagnosed in third trimester pregnancy and pregnancy outcome

BACKGROUND

The clinical significance of gestational diabetes diagnosed in the third trimester is unclear. A prospective observational study was performed on a cohort of women without pre-existing gestational diabetes or other medical disorders to examine the effect of gestational diabetes on pregnancy complications and infant outcome.

METHODS

Four hundred and eighty-nine consecutive women were assessed at 28-30 weeks by random glucose screening and/or a 75 g oral glucose tolerance test. The subsequent management was according to established departmental protocols. The outcome of pregnancy was compared among the groups with negative screening, positive screening but normal glucose tolerance, and gestational diabetes which was controlled with diet therapy.

RESULTS

Women with gestational diabetes (n=67 or 13.7%) had significantly increased maternal age, pre-pregnancy weight and body mass index, hemoglobin levels at booking and at 36-38 weeks, and incidences of parity >1, pre-eclampsia, and female infants, while the gestational age was shorter and there was no significant difference in the birthweight outcome or neonatal morbidity.

CONCLUSIONS

Despite diet treatment, gestational diabetes diagnosed in the last trimester is associated with increased risk of pre-eclampsia and shorter length of gestation, and this is likely to reflect a pathological process rather than the physiological effect of pregnancy on maternal glucose tolerance.