Aetiology of gestational diabetes

The association between second trimester ultrasound fetal biometrics and gestational diabetes

OBJECTIVE

Gestational diabetes mellitus (GDM) is the most common metabolic complication of pregnancy. The incidence of GDM is increasing worldwide and 5-25% of pregnancies are diagnosed with GDM depending on screening strategies and diagnostic criteria. GDM may lead to obstetric complications and increases the risk of adult metabolic disease in the offspring. Timely identification of GDM allows for regulation of maternal glucose levels which may reduce the obstetric complications considerably. The aim of this study is to investigate the association between second trimester ultrasound biometrics and GDM.

STUDY DESIGN

This is a retrospective cohort study including 2697 singleton pregnancies attending second trimester ultrasound scan at 20 + 0 to 20 + 6 weeks' gestation and giving birth at Aalborg University Hospital in the year 2020. Ultrasound measurements included head circumference (HC), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW) by Hadlock's formula. Women with pregestational diabetes were excluded. GDM screening was performed on indication using oral-glucose-tolerance-test (OGTT) including 75 g glucose and a 2-hour serum glucose value ≥ 9 mmol/L was considered diagnostic. The association between fetal biometrics and GDM was investigated by logistic regression.

RESULTS

A total of 174 (6.5 %) were diagnosed with GDM. The incidence of GDM in pregnancies with biometrics above the 90th centile was; FL: 10.5 %, HC: 8.8 %, AC: 7.6 %, EFW: 9.3 %. Fetal biometrics above the 90th centile was significantly associated with GDM; OR_FL = 2.07, p = 0.001; OR_HC = 1.89, p = 0.001; OR_AC = 1.63, p = 0.033; OR_EFW = 1.64, p = 0.036. This association remained significant for HC and FL when adjusted for maternal obesity (Body Mass Index ≥ 27): OR_HC(adj)=1.56, p = 0.019; OR_FL(adj) = 1.57, p = 0.049.

CONCLUSION

At the second trimester scan, fetal biometrics above the 90th centile increase the risk of GDM. In pregnancies that are later diagnosed with GDM fetal growth is increased already at the second trimester scan. Such knowledge underlines the importance of early identification of GDM.

Modelling gestational diabetes mellitus: large animals hold great promise

Gestational diabetes mellitus (GDM) characterized by hyperglycemia during pregnancy is a risk factor for various maternal and fetal complications. The key pathophysiological mechanisms underlying its development have not been elucidated, largely due to the lack of a model that accurately simulates the major clinical and pathological features of human GDM. In this review, we discuss the refined criteria for an ideal animal model of GDM, focusing on the key clinical and pathophysiological characteristics of human GDM. We provide a comprehensive overview of different models and currently used species for GDM research. In general, insulin insufficiency consequent to pancreatic β-cell death represents the current leading strategy to mimic human GDM-like hyperglycemia in animals. Nonetheless, these models have a limited capacity to mimic the natural history of GDM, the marked alteration in circulating estrogen/ progestogen, obesity and its related metabolic complications. We discuss emerging evidence of the increased susceptibility to GDM in rodents and large animals with genetic modifications in pregnancy-related hormones. An appraisal of current GDM models suggests that a combination strategy involving dietary stress, pregnancy-related hormones, insulin resistance and metabolic disorders might enable the development of better GDM models and expedite the translation of basic research findings to GDM treatment.

Pregnancy rest-activity patterns are related to salivary cortisol rhythms and maternal-fetal health indicators in women from a disadvantaged population

Irregular rest-activity patterns can disrupt metabolic and hormonal physiology and potentially lead to disease. Little is known regarding rest-activity patterns during gestation and their association with hormonal rhythms and health in pregnant women. We conducted a pilot study to determine if 24 h rest-activity was related to saliva cortisol rhythms and maternal-fetal health in an economically disadvantaged population. Primiparous women wore a wrist actigraphy device for a week to record activity during gestational weeks 22 (G22; n = 50) and 32 (G32; n = 46) and postpartum week one (PPW1; n = 39). Participants collected saliva samples every 4 hr over a 24 hr period during G22 (n = 22), G32 (n = 20) and 24–48 hr postnatal (n = 20), and cortisol concentrations were measured with ELISA. Circadian rhythmicity was assessed using autocorrelation coefficient (r24) and cosinor analysis. Blood glucose levels, body mass index (BMI), gestational disease data, and gestational age of infant at birth were abstracted from medical charts. Time of cortisol peak (acrophase) during G22 was related with acrophase of activity (r = 0.66; p = 0.001) and blood glucose levels (r = 0.58; p = 0.006). During G22, minutes of wake after sleep onset was positively related to cortisol mesor and AUC (p <0.05). Rest-activity r24, R², and mesor during G32 were positively (p<0.05) associated with gestational age of infant at birth. Across all three time points r24 of activity was related with cortisol amplitude (r = 0.33; p = 0.01). Findings support a relationship between rest-activity patterns and saliva cortisol rhythms during pregnancy. The association of less robust activity rhythms with earlier gestational age of infant at birth indicates a potential link between circadian system disruption and maternal-fetal health outcomes.

Role of mean platelet volume in pregnancy to predict gestational diabetes mellitus in the first trimester

Objectives: Gestational diabetes mellitus (GDM) is defined as glucose intolerance detected for the first time in pregnancy or identified during pregnancy. Mean platelet volume (MPV) is a marker of activation and function of platelet. Several studies investigated the relation between MPV and GDM. The purpose of the present study is to predict GDM in the first trimester by using MPV value.Materials and methods: Two hundred pregnant women with GDM and 200 normal pregnant women were enrolled in the study. The first trimester MPV values of GDM and control groups were compared to predict GDM in the first trimester.Results: Women with GDM had higher MPV value compared with the control group (p < .001). The area under the receiver-operator curve was 0.70 for MPV. The cutoff value of MPV was 7.38 fl with 70% sensitivity and 60% specificity. According to the ages, MPV value was higher in GDM group in the individuals who were above 28-year-old (p < .001).Conclusion: MPV can be used to predict GDM in the first trimester.

Identification of biological processes and genes for gestational diabetes mellitus

AIM

Gestational diabetes mellitus (GDM) is one of the most usual complications of pregnancy, while the correlations between genes and their known biological processes need to be further elucidated.

METHODS

In the current study, microarray data GSE2956 containing a list of 435 significantly modified genes (differentially expressed genes, DEGs) were used. Genes that correspond to official gene symbols were chosen and were functional annotated for Gene Ontology (GO) and pathway analyses (p ≤ 0.05). Then, the protein-protein interaction (PPI) network and the sub network were constructed and analyzed (combined score ≥0.4).

RESULTS

A total of 405 DEGs including 239 up-regulated and 166 down-regulated genes were screened, and they were found mainly related to adhesion and motion, stimulus-response, and wound healing, etc. Besides, a PPI network containing 217 nodes and 644 lines was obtained. Hub genes including fibronectin 1 (FN1) and insulin-like growth factor 1 (IGF1) were down-regulated, and leptin (LEP) and calmodulin 1 (CALM1) were up-regulated. Three modules in the PPI network were mined and similar functional terms enriched by DEGs of these modules were obtained.

CONCLUSION

GO terms relevant to translation and metabolic process and their related genes CREB1, ribosomal proteins and LEP, still the inflammation-related proteins (e.g., IGF1 and CALM1) and cell adhesion-related protein FN1 may work together and be essential for GDM. This study provides insight into the cooperative interactions of metabolism and immune responses and the pathogenesis of GDM.

Gestational diabetes as one of the "great obstetrical syndromes"--the maternal, placental, and fetal dialog

Gestational diabetes mellitus (GDM)-associated fetal and neonatal adverse outcome results from the metabolic milieu projected on the fetus via the placental interface. Therefore, it can be considered to be one of the great obstetrical syndromes. Placentas from GDM pregnancies differ from nondiabetic pregnancies by an increased placental to fetal ratio and by histological findings such as villous fibrinoid necrosis, villous immaturity, chorangiosis, and ischemic changes. While early onset diabetes is more associated with marked structural changes of the placenta, GDM that rises at late gestation is associated more with placental functional changes. These placental changes, causing increased intervillous diffusion distance of immature villi and placental size to perfusion mismatch, may predispose the fetus to chronic and acute changes in gas and nutrient exchange thus turning the placenta from being a "fetus protector" to a potential source of adverse outcome. Understanding placental changes and how they affect outcome is necessary in order to develop effective screening, prevention, and management approaches.

Effect of pregnancy for females born small on later life metabolic disease risk

There is a strong inverse relationship between a females own birth weight and her subsequent risk for gestational diabetes with increased risk of developing diabetes later in life. We have shown that growth restricted females develop loss of glucose tolerance during late pregnancy with normal pancreatic function. The aim of this study was to determine whether growth restricted females develop long-term impairment of metabolic control after an adverse pregnancy adaptation. Uteroplacental insufficiency was induced by bilateral uterine vessel ligation (Restricted) or sham surgery (Control) in late pregnancy (E18) in F0 female rats. F1 Control and Restricted female offspring were mated with normal males and allowed to deliver (termed Ex-Pregnant). Age-matched Control and Restricted Virgins were also studied and glucose tolerance and insulin secretion were determined. Pancreatic morphology and hepatic glycogen and triacylglycerol content were quantified respectively. Restricted females were born lighter than Control and remained lighter at all time points studied (p<0.05). Glucose tolerance, first phase insulin secretion and liver glycogen and triacylglycerol content were not different across groups, with no changes in β-cell mass. Second phase insulin secretion was reduced in Restricted Virgins (-34%, p<0.05) compared to Control Virgins, suggestive of enhanced peripheral insulin sensitivity but this was lost after pregnancy. Growth restriction was associated with enhanced basal hepatic insulin sensitivity, which may provide compensatory benefits to prevent adverse metabolic outcomes often associated with being born small. A prior pregnancy was associated with reduced hepatic insulin sensitivity with effects more pronounced in Controls than Restricted. Our data suggests that pregnancy ameliorates the enhanced peripheral insulin sensitivity in growth restricted females and has deleterious effects for hepatic insulin sensitivity, regardless of maternal birth weight.

Does pregnancy or pregnancy loss increase later maternal risk of diabetes?

Evidence that childbearing is associated with future development of diabetes remains conflicting and the role of pregnancy loss in this association has not been investigated. We aimed to examine whether pregnancy and/or pregnancy loss (miscarriage, abortion, or stillbirth) are associated with maternal higher risk of diabetes later in life, using a population-based prospective cohort study (mean follow-up = 10.7 years), including 13,612 women (aged 35-65 at baseline). We found pregnancy per se did not change the risk of diabetes after considering the effect of education, smoking, alcohol consumption, physical activity, BMI, waist/hip ratio, hypertension, and hyperlipidemia (fully-adjusted OR: 1.04, 95 % CI: 0.82-1.31). Having more than four live births was associated with around two times higher risk of diabetes later in life (fully-adjusted OR: 1.77, 95 % CI: 1.12-2.80). Having more than two miscarriages was associated with about two-fold higher risk of diabetes (fully-adjusted Odd ratio (OR): 1.85, 95 % CI: 1.17-2.93). After further adjustment for parity, the higher risk of diabetes in those who had history of more than two miscarriages did not change substantially (OR: 1.82; 95 % CI: 1.15-2.88), but the association between more than four live births and diabetes disappeared when the role of pregnancy loss was considered (fully-adjusted HR: 1.06; 95 % CI: 0.54-2.08). No significant association was found between abortion, stillbirth and risk of maternal diabetes. Pregnancy per se did not increase risk of diabetes. Women who experience more than two miscarriages are at around two times higher risk of diabetes later in life. The association between high parity and diabetes is mediated by history of miscarriages and known risk factors of diabetes. The underlying reason for association between miscarriage and diabetes needs further investigation.

Maternal adaptations and inheritance in the transgenerational programming of adult disease

Adverse exposures in utero have long been linked with an increased susceptibility to adult cardio-renal and metabolic diseases. Clear gender differences exist, whereby growth-restricted females, although exhibiting some phenotypic modifications, are often protected from overt disease outcomes. One of the greatest physiological challenges facing the female gender, however, is that of pregnancy; yet little research has focused on the outcomes associated with this, as a potential 'second-hit' for those who were small at birth. We review the limited evidence suggesting that pregnancy may unmask cardio-renal and metabolic disease states and the consequences for long-term maternal health in females who were born small. Additionally, a growing area of research in this programming field is in the transgenerational transmission of low birth weight and disease susceptibility. Pathways for transmission might include an abnormal adaptation to pregnancy by the growth-restricted mother and/or inheritance via the parental germline. Strategies to optimise the pregnancy environment and/or prevent the consequences of inheritance of programmed deficits and dysfunction are of critical importance for future generations.

Dyslipidemia in pregnancy may contribute to increased risk of neural tube defects -a pilot study in north Indian population

Neural tube defects are congenital structural abnormalities of the brain and vertebral column resulting from improper or non-timely closure of the neural tube. Prevalence of neural tube defects is reported to be higher among women with diabetes mellitus and obesity. This study was designed to investigate the relation between the presence of dyslipidemia in antenatal patients and the risk of fetal neural tube defects. The present study was an observational, cross-sectional study involving 129 pregnant women in 16 to 18 weeks gestation period. Of these, 80 women had normal pregnancies and 49 were clinically high-risk cases for neural tube defects. Fasting blood samples were analyzed for blood sugar and lipid profile by enzymatic assay and alpha-fetoprotein levels using Enzyme Immunoassay. Alpha-fetoprotein (AFP) values were converted to Multiples of Median (MoM) appropriate for the gestational age. Based on AFP values, women were labeled as screen negative (AFP <2 MoM, n= 102) and screen positive (AFP > 2 MoM, n =27). Screen positive women were further evaluated by ultrasound and 21 women were found to carry a neural tube defects positive pregnancy. Statistical analysis was done on SPSS software. Body weight of the women showed a significant positive correlation with serum triglycerides, plasma sugar and AFP MoM values. A significant difference was observed in serum cholesterol levels (p= 0.038), triglycerides (p=0.001) and plasma sugar levels (p=0.002) between normal women and those with neural tube defects positive pregnancy. The Odds ratio for neural tube defects risk in dyslipidemic cases was 24.23 (CI 4.73 - 148.60) with a relative risk of 12.12. Dyslipidemia especially hypertriglyceridemia was found to be significantly associated with fetal neural tube defects.

Visfatin in human pregnancy: maternal gestational diabetes vis-à-vis neonatal birthweight

OBJECTIVE

Adipose tissue dysfunction, characterized by dysregulation of adipokines production and/or secretion, has been implicated in the pathophysiology of type-2 diabetes mellitus, a metabolic complication closely related to gestational diabetes mellitus (GDM). Recently, an association between circulating maternal visfatin, a novel adipokine with metabolic and immunoregulatory properties, and impaired glucose metabolism as well as with altered fetal growth, has been proposed. The aims of this study were to determine whether there is an association between maternal plasma visfatin concentration, GDM, and a large-for-gestational-age (LGA) newborn.

STUDY DESIGN

This cross-sectional study, included pregnant women at term in the following groups: 1) normal pregnancy and an appropriate-for-gestational-age (AGA) neonate (n=54); 2) normal pregnancy and an LGA newborn (n=47); 3) GDM and an AGA newborn (n=56); 4) GDM and an LGA newborn (n=45). The study population was further stratified by first trimester BMI (<25 vs. > or =25 kg/m(2)). Maternal plasma visfatin concentration was determined by ELISA. Parametric and non-parametric statistics were used for analysis.

RESULTS

1) Among women who delivered an AGA neonate, the median maternal plasma concentration of visfatin was higher in patients with GDM than in those with a normal pregnancy; 2) Among women with a normal pregnancy, those who delivered an LGA neonate had a higher median maternal plasma visfatin concentration than those who delivered an AGA neonate; 3) among patients with normal BMI, there were no significant differences in the median maternal plasma visfatin concentration between the four study groups; and 4) maternal GDM, as well as delivery of an LGA neonate were independently associated with a higher maternal plasma visfatin concentrations.

CONCLUSION

The linkage between increased maternal circulating visfatin and the presence of GDM or delivery of an LGA neonate supports the hypothesis that perturbation of adipokines homeostasis may play a role in the pathophysiology of GDM or excess fetal growth.

Maternal visfatin concentration in normal pregnancy

OBJECTIVE

Adipose tissue has now emerged as a powerful endocrine organ via the production of adipokines. Visfatin, a novel adipokine with diabetogenic and immuno-modulatory properties has been implicated in the pathophysiology of insulin resistance in patients with obesity and Type-2 diabetes mellitus. The aim of this study was to determine whether there are changes in the maternal plasma concentration of visfatin with advancing gestation and as a function of maternal weight.

STUDY DESIGN

In this cross-sectional study, maternal plasma concentrations of visfatin were determined in normal weight and overweight/obese pregnant women in the following gestational age groups: 1) 11-14 weeks (n=52); 2) 19-26 weeks (n=68); 3) 27-34 weeks (n=93); and 4) >37 weeks (n=60). Visfatin concentrations were determined by ELISA. Non parametric statistics were used for analysis.

RESULTS

1) The median maternal plasma visfatin concentration was higher in pregnant women between 19-26 weeks of gestation than that of those between 11-14 weeks of gestation (P<0.01) and those between 27-34 weeks of gestation (P<0.01); 2) among normal weight pregnant women, the median plasma visfatin concentrations of women between 19-26 weeks of gestation was higher than that of those between 11-14 weeks (P<0.01) and those between 27-34 weeks (P<0.01); and 3) among overweight/obese patients, the median maternal visfatin concentration was similar between the different gestational age groups.

CONCLUSION

The median maternal plasma concentration of visfatin peaks between 19-26 and has a nadir between 27-34 weeks of gestation. Normal and overweight/obese pregnant women differed in the pattern of changes in circulating visfatin concentrations as a function of gestational age.

Adiponectin multimers in maternal plasma

OBJECTIVE

Adiponectin is an anti-diabetic, anti-atherogenic, anti-inflammatory, and angiogenic adipokine that circulates in oligomeric complexes including: low molecular weight (LMW) trimers, medium molecular weight (MMW) hexamers, and high molecular weight (HMW) isoforms. The aim of this study was to determine whether there are changes in adiponectin multimers in pregnancy and as a function of maternal weight.

STUDY DESIGN

In this cross-sectional study, plasma concentrations of total, HMW, MMW, and LMW adiponectin were determined in women included in three groups: (1) normal pregnant women of normal body mass index (BMI) (n = 466), (2) overweight pregnant women (BMI >or=25; n = 257), and (3) non-pregnant women of normal weight (n = 40). Blood samples were collected once from each woman between 11 and 42 weeks of gestation. Plasma adiponectin multimer concentrations were determined by enzyme-linked immunosorbent assay (ELISA). Non-parametric statistics were used for analysis.

RESULTS

(1) The median HMW adiponectin concentration and the median HMW/total adiponectin ratio were significantly higher, and the median LMW adiponectin concentration was significantly lower in pregnant women than in non-pregnant women. (2) Among pregnant women, the median plasma concentration of total, HMW, and MMW adiponectin was significantly higher in normal weight women than in overweight patients. (3) Maternal HMW was the most prevalent adiponectin multimer regardless of gestational age or BMI status. (4) There were no significant differences in the median concentration of total, MMW, and LMW adiponectin and their relative distribution with advancing gestation.

CONCLUSION

Human pregnancy is characterized by quantitative and qualitative changes in adiponectin multimers, especially the most active isoform, HMW adiponectin.

Resistin: a hormone which induces insulin resistance is increased in normal pregnancy

AIMS

Resistin, a newly discovered adipokine, is thought to play a key role in the regulation of insulin resistance. The objectives of this study were to develop a nomogram of maternal plasma concentrations of resistin from 11 weeks of gestation to term and to determine whether resistin concentrations differ between normal and overweight pregnant women.

METHODS

In this cross-sectional study, plasma concentrations of resistin were determined in normal pregnant women of normal body mass index (BMI 18.5-24.9; n=261), overweight pregnant women (BMI > or =25; n=140), and non-pregnant women of normal BMI (n=40). Blood samples were collected once from each woman between the first trimester and term. Percentiles for resistin concentration were determined for five pre-specified windows of gestational age. Plasma resistin concentration was determined by immunoassay. Non-parametric statistics were used for analysis.

RESULTS

The median maternal plasma concentration of resistin between 11 to 14 weeks of gestation in women of normal weight was significantly higher than non-pregnant women; the plasma concentration of resistin increased with gestational age.

CONCLUSIONS

Normal pregnant women have a higher median plasma concentration of resistin than non-pregnant women and the concentration of this adipokine increases with advancing gestation. Alterations in the maternal plasma concentration of resistin during pregnancy could contribute to metabolic changes of pregnancy.

A population-based screening for gestational diabetes mellitus in non-diabetic women in Bahrain

BACKGROUND

Maternal hyperglycemia is considered a risk factor for fetal morbidity. Since there is a high prevalence of diabetes mellitus among the population of Bahrain, we conducted a prospective population-based study of gestational diabetes mellitus (GDM) in non-diabetic pregnant women.

SUBJECTS AND METHODS

All non-diabetic pregnant women attending antenatal clinics during January 2001 to December 2002 (n=10,495) were screened for GDM during the 24th to 28th weeks of gestation. All positive subjects based on a 50-g glucose challenge test (GCT) were further evaluated by a diagnostic 75-g oral glucose tolerance test (OGTT). The birth weight of the child and post-delivery insulin resistance were monitored. The homeostasis model of insulin resistance (HOMA-IR) was used to assess insulin resistance.

RESULTS

Of 10,495 non-diabetic pregnant women screened, 32.8% (n=3443) had plasma glucose > or = 7.8 mmol/L (140 mg/dL) in the GCT. The 75-g OGTT found a prevalence of GDM of 13.5%. There were twice as many Bahrainis as expatriates. Of children born to women with GDM, 6.5% had a birth weight > 4000 g. Post-delivery evaluation of insulin resistance indicated that 33% of women with GDM had a HOMA-IR value > 2.

CONCLUSION

The population of Bahrain is a high-risk ethnic group for GDM. The association of insulin resistance in the post-gravid state with GDM among 33% of the study population suggests that insulin resistance, the possible cause of the pathophysiological mechanism underlying the development of gestational diabetes, continues in the post gravid state.

Prevalence of gestational diabetes mellitus in Kashmiri women from the Indian subcontinent

This prospective study was carried out to determine the prevalence of gestational diabetes mellitus (GDM) in Kashmiri women and to assess the effect of various demographic factors. Two thousand pregnant women (divided into groups A and B, being the first and last 1000 consecutive women) attending various antenatal clinics in six districts of Kashmir valley were screened for GDM by 1 h 50 g oral glucose challenge test. Four hundred and fourteen (20.8%) women (216 from group A and 198 from group B) had an abnormal screening test and proceeded to oral glucose tolerance testing. Women from group A had a 3 h 100 gram oral glucose tolerance test (OGTT) and GDM was as classified by Carpenter and Coustan. A 2 h 75 g OGTT was performed on group B subjects and WHO criteria applied for diagnosis of GDM. The overall prevalence of GDM was 3.8% (3.1% in group A versus 4.4% in group B-P-value 0.071). GDM prevalence steadily increased with age (from 1.7% in women below 25 years to 18% in women 35 years or older). GDM occurred more frequently in women who were residing in urban areas, had borne three or more children, had history of abortion(s) or GDM during previous pregnancies, had given birth to a macrosomic baby, or had a family history of diabetes mellitus. Women with obesity, hypertension, osmotic symptoms, proteinuria or hydramnios had a higher prevalence of GDM.

A cohort study of reproductive risk factors, weight and weight change and the development of diabetes mellitus

AIMS

Reproductive factors (parity, miscarriages, terminations), oral contraceptive use, hormone replacement therapy, body weight at first pregnancy and weight gain following pregnancy may be associated with a long-term risk of diabetes. The aim of this study is to investigate the independent risks of reproductive factors and body weight for diabetes in later life.

METHODS

This is a retrospective cohort study of 1257 parous women who had a first pregnancy between 1951 and 1970. Reproductive history, weight and height were measured at the time of first pregnancy, then assessed by questionnaire in 1997 for all women. A clinical examination and an analysis of blood samples were undertaken for 992 women. The main outcome was incidence of diabetes based on medical history, medication and random glucose measurement.

RESULTS

Sixty of the 1257 (4.8%) women developed diabetes. Body mass index at index pregnancy and after 28-48 years follow-up were both significantly associated with risk of diabetes, this increased with greater weight gain. There was a non-significant increased risk of diabetes associated with stillbirths and miscarriages after age and BMI adjustment.

CONCLUSIONS

In parous women, higher BMI at index pregnancy, weight gain during follow-up and BMI in later life strongly predict diabetes risk.

Progesterone receptor knockout mice have an improved glucose homeostasis secondary to beta -cell proliferation

Gestational diabetes coincides with elevated circulating progesterone levels. We show that progesterone accelerates the progression of diabetes in female dbdb mice. In contrast, RU486, an antagonist of the progesterone receptor (PR), reduces blood glucose levels in both female WT and dbdb mice. Furthermore, female, but not male, PR-- mice had lower fasting glycemia than PR++ mice and showed higher insulin levels on glucose injection. Pancreatic islets from female PR-- mice were larger and secreted more insulin consequent to an increase in beta-cell mass due to an increase in beta-cell proliferation. These findings demonstrate an important role of progesterone signaling in insulin release and pancreatic function and suggest that it affects the susceptibility to diabetes.

From "thrifty genotype" to "hefty fetal phenotype": the relationship between high birthweight and diabetes in Saskatchewan Registered Indians

BACKGROUND

Intrauterine factors have been implicated in the pathogenesis of Type 2 diabetes mellitus (T2DM).

METHODS

In a 1:1 matched pairs case-control study, high and low birthweight (HBW, LBW) rates in Saskatchewan Registered Indian (RI) diabetic cases were compared with corresponding rates in RI without diabetes, and non-RI people with and without diabetes.

RESULTS

Birthweights were available for 73% of the 1,366 cases and 3 x 1,366 controls. A greater proportion of RI diabetics were born with HBW (> 4000 grams) compared to RI non-diabetics (16.2% vs 10.7%; p < 0.01). There was a significant association between HBW (but not LBW [< 2500 grams]) and diabetes for RI people (OR 1.63 [95% CI 1.20, 2.24]), which was stronger for RI females and strengthened progressively from mid to late 20th century.

INTERPRETATION

Certain causes of HBW may predispose to subsequent development of T2DM in Canadian Aboriginal people ("hefty fetal phenotype" ["hefty fetal type"] hypothesis). Programs that optimize healthy pregnancies could reduce T2DM incidence in future generations.

Carbohydrate and lipid metabolism in pregnancy: normal compared with gestational diabetes mellitus

This article reviews maternal metabolic strategies for accommodating fetal nutrient requirements in normal pregnancy and in gestational diabetes mellitus (GDM). Pregnancy is characterized by a progressive increase in nutrient-stimulated insulin responses despite an only minor deterioration in glucose tolerance, consistent with progressive insulin resistance. The hyperinsulinemic-euglycemic glucose clamp technique and intravenous-glucose-tolerance test have indicated that insulin action in late normal pregnancy is 50-70% lower than in nonpregnant women. Metabolic adaptations do not fully compensate in GDM and glucose intolerance ensues. GDM may reflect a predisposition to type 2 diabetes or may be an extreme manifestation of metabolic alterations that normally occur in pregnancy. In normal pregnant women, basal endogenous hepatic glucose production (R(a)) was shown to increase by 16-30% to meet the increasing needs of the placenta and fetus. Total gluconeogenesis is increased in late gestation, although the fractional contribution of total gluconeogenesis to R(a), quantified from (2)H enrichment on carbon 5 of glucose (65-85%), does not differ in pregnant women after a 16-h fast. Endogenous hepatic glucose production was shown to remain sensitive to increased insulin concentration in normal pregnancy (96% suppression), but is less sensitive in GDM (80%). Commensurate with the increased rate of glucose appearance, an increased contribution of carbohydrate to oxidative metabolism has been observed in late pregnancy compared with pregravid states. The 24-h respiratory quotient is significantly higher in late pregnancy than postpartum. Recent advances in carbohydrate metabolism during pregnancy suggest that preventive measures should be aimed at improving insulin sensitivity in women predisposed to GDM. Further research is needed to elucidate the mechanisms and consequences of alterations in lipid metabolism during pregnancy.

Maternal physical activity in pregnancy and infant size for gestational age

PURPOSE

To estimate the effect of several types of maternal physical activity in pregnancy on size for gestational age and length of gestation.

METHODS

Telephone interviews, birth certificates, and medical records provided data on physical activity and other factors for a random sample of 291 Colorado residents. Backward polychotomous logistic regression modeling yielded estimates of the odds ratios for size for gestational age (appropriate versus small or large) and length of gestation (term versus pre-term or post-term) in relation to second and third trimester maternal physical activity.

RESULTS

Performance of any moderate or vigorous physical activity for two hours per week or more in any month was associated with a decreased risk of large infant size for gestational age (LGA; odds ratio = 0.3, 95% confidence interval = 0.2, 0.7), but had no significant effect on risk of small infant size for gestational age (SGA; odds ratio (OR) = 0.8, 95% confidence interval (CI) = 0.3, 2.3). Length of gestation was not affected by prenatal physical activity.

CONCLUSIONS

These results suggest that prenatal physical activity may decrease risk of LGA, as might be expected given its salutary effects on glucose tolerance.

Why do Asian-born women have a higher incidence of gestational diabetes? An analysis of racial differences in body habitus, lipid metabolism and the serum insulin response to an oral glucose load

We have observed a higher incidence of gestational diabetes (GDM) in Asian-born than in Caucasian women. Body habitus, serum lipid levels and the serum insulin response to a glucose load in pregnancy were compared in 15 women with normal glucose tolerance, 16 Caucasian women with GDM and 19 Asian-born women with GDM. Caucasian women with GDM, unlike Asian-born women with GDM, were obese compared with control women as measured by body mass index (p = 0.022). Both groups of GDM women had similar patterns of insulin response to oral glucose with a delayed insulin peak and an elevated 2-hour insulin level (p = 0.0021). In addition, the insulin response per unit of glycaemic stimulus (incremental insulin area/incremental glucose area at 1 hour) was reduced in both GDM groups (p = 0.035). Fasting serum triglyceride levels were higher in women with GDM although this was only significant in the Caucasian group (p = 0.014). Asian-born women with GDM had significantly lower (p = 0.041) serum cholesterol levels than Caucasian women with GDM. There was a significant correlation (p = 0.025) between glucose tolerance (area under the curve) and fasting serum triglyceride values. The relationship between lipid and carbohydrate metabolism in Asian-born and Caucasian women in pregnancy requires further investigation.