Effect of Curcumin Nanoemulsion on Brain Cell Development, Locomotor Function, and Mortality of Zebrafish Larvae Model of Gestational Diabetes Mellitus

Background: Women with gestational diabetes mellitus (GDM), a condition of pregnancy-induced hyperglycemia, are more likely to develop cardiovascular disease (CVD) within 3 to 10 years following pregnancy. One reason for the lack of progress into the cardiovascular complications of GDM is the need for appropriate preclinical models that mimic human GDM. We have previously used the insulin receptor antagonist (S961) to develop a novel hormonal mouse model of reversible GDM. Hypothesis: We hypothesized that S961-induced GDM mice will exhibit CVDs later in life. Aim: To determine the mechanisms underlying CVD in hormonal model of GDM. Methods: Sixteen (16) week-old C57BL/6J female mice were treated with S961 or saline (n=4) from the second trimester of pregnancy until delivery to develop hormonal mouse model of GDM. Animals were followed up to 10 weeks after gestation. Blood glucose levels were measured with a glucometer. Fasting insulin, circulating endothelin-1 (ET-1) and nitrite were measured by colorimetry. Cardiac structure and function were measured by high resolution ultrasound echocardiography (VEVO 3100) and pulse wave velocity was measured by Pulse Wave Doppler (Indus instrument). Exercise tolerance test was performed on treadmill (Columbus Instrument). Aortic sirtuin-1 (SIRT-1) and ETA receptor were determined by western blot. Vascular reactivity was determined by wire myograph (DMT). Aortic fibrosis and calcification were determined by picrosirius red and Von Kossa staining. Data were analyzed by unpaired t- tests and results are expressed as mean ± standard error of mean. Results: S961-induced GDM mice exhibit hyperglycemia (169.5 ± 3.6 vs. 105.5 ± 10.8mg/dL, p<0.004 ) and hyperinsulinemia (1.9 ± 0.2 vs. 0.8 ± 0.1ng/ml , p<0.01 ) which mimics the condition observed in human GDM. Interestingly, S961-induced GDM mice went on to develop systolic and diastolic dysfunction, vascular stiffness (3.7 ± 0.1 vs. 3.1 ± 0.08 m/s, p <0.005 ), exercise intolerance and increased thickness of the cardiac wall at 10 weeks post-delivery. Plasma ET-1 was elevated in our model during pregnancy (28.1 ± 1.7 vs. 5.2 ± 0.2pg/ml, p <0.002 ) and at 10 weeks post-delivery (19.9 ± 2.9 vs. 6.7 ± 0.7pg/ml, p <0.05 ). Circulating NO and aortic expression of SIRT-1, that is involved in endothelial longevity by regulating endothelial NO synthase, is reduced in GDM mice. Vascular relaxation to acetylcholine was impaired in S961-induced GDM compared to control. Additionally, GDM mice exhibited increased arterial wall thickness, collagen accumulation, and calcium deposits in the wall of aorta. Conclusion: Insulin receptor antagonist (S961)-treated mice develop GDM similar to that observed in pregnant women. Moreover, S961 treated mice develop cardiac dysfunction and vascular stiffness at 10 weeks post-delivery. Alterations in ET-1, SIRT-1, NO levels, aortic fibrosis and calcification may be responsible for the development of CVD in this model. Funding: NIH-NIDDK (1R01DK121748-01A1), AHA Postdoctoral Award (23POST1020493), NIH-COBRE Pilot Grant (SP15081) and NIGMS (P20GM104357 & P30GM149404 ). This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.

Currently, there is no international unanimity regarding the timings, the optimal cut-off points, and standardized methods of screening or diagnosis of gestational diabetes mellitus (GDM). The screening guidelines and recommendations for GDM evolved over time; concise information has been presented here in the review. We searched electronic databases for various guidelines for screening of GDM in PubMed, Medical Literature Analysis and Retrieval System Online (MEDLINE), Embase, Cochrane, Google Scholar, Scopus, Guidelines International Network (GIN library), National Guidelines Clearinghouse (NGC); Web sites of relevant organizations; and trial registries. The mesh headings derived after reviewing the articles and were used to further search the articles are: ("Screening Guidelines GDM" or "Screening Criteria for GDM") and ("Glucose Intolerance in Pregnancy" or "Gestational Diabetes Mellitus"). The articles published from 1960 till December 2022 were included. Key outcomes included the prevalence of GDM is 14.6% according to the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria and 13.4% according to Diabetes in Pregnancy Study Group India (DIPSI) criteria, making the DIPSI criterion a cost-effective method for low-resource settings. The IADPSG) criterion diagnoses and treats GDM earlier, thus reducing the complications associated with GDM in the mother and newborn. The IADPSG criteria at a cut-off of ≥140 mg/dL have a sensitivity of 81% and specificity of 93%, whereas the World Health Organization (2013) criteria at the same cut-off has a lower sensitivity of 59% and specificity of 81%. The risk factors of having GDM are family history, history during past pregnancy, medical history, multiple current pregnancies, and raised hemoglobin A1c. The screening guidelines have been developed by different organizations and institutions over the years. The guidelines with the threshold values for screening and their standardization for detecting GDM in Indian mothers are yet to be established.

Gestational diabetes mellitus (GDM) and even mild glucose intolerance in pregnancy are both associated with increased risks of developing type 2 diabetes and cardiovascular disease in the future. Because the metabolic syndrome also identifies patients at risk of type 2 diabetes and cardiovascular disease, we hypothesized that gestational dysglycemia may be associated with an unrecognized latent metabolic syndrome. Thus, we sought to evaluate the relationship between gestational glucose tolerance status and postpartum risk of metabolic syndrome. In this prospective cohort study, 487 women underwent oral glucose tolerance testing in pregnancy and cardiometabolic characterization at 3 months postpartum. The antepartum testing defined three gestational glucose tolerance groups: GDM (n = 137); gestational impaired glucose tolerance (GIGT) (n = 91); and normal glucose tolerance (NGT) (n = 259). The primary outcome was the presence of the metabolic syndrome at 3 months postpartum, as defined by International Diabetes Federation (IDF) and American Heart Association/National Heart Lung and Blood Institute (AHA/NHLBI) criteria, respectively. The postpartum prevalence of IDF metabolic syndrome progressively increased from NGT (10.0%) to GIGT (17.6%) to GDM (20.0%) (overall P = 0.016). The same progression was observed for AHA/NHLBI metabolic syndrome (NGT, 8.9%; GIGT, 15.4%; and GDM, 16.8%; overall P = 0.046). On logistic regression analysis, both GDM (odds ratio, 2.05; 95% confidence interval, 1.07-3.94) and GIGT (odds ratio, 2.16; 95% confidence interval, 1.05-4.42) independently predicted postpartum metabolic syndrome. Both GDM and mild glucose intolerance in pregnancy predict an increased likelihood of metabolic syndrome at 3 months postpartum, supporting the concept that women with gestational dysglycemia may have an underlying latent metabolic syndrome.

We previously developed a model of gestational diabetes mellitus (GDM) in which dams exhibit glucose intolerance, insulin resistance, and reduced insulin response to glucose challenge only during pregnancy, without accompanying obesity. Here, we aimed to determine how lean gestational glucose intolerance affects offspring risk of metabolic dysfunction. One cohort of offspring was sacrificed at 19 weeks, and one at 31 weeks, with half of the second cohort placed on a high-fat, high-sucrose diet (HFHS) at 23 weeks. Exposure to maternal glucose intolerance increased weights of HFHS-fed offspring. Chow-fed offspring of GDM dams exhibited higher body fat percentages at 4, 12, and 20 weeks of age. At 28 weeks, offspring of GDM dams fed the HFHS but not the chow diet (CD) also had higher body fat percentages than offspring of controls (CON). Exposure to GDM increased the respiratory quotient (Vol CO2/Vol O2) in offspring. Maternal GDM increased adipose mRNA levels of peroxisome proliferator-activated receptor gamma (Pparg) and adiponectin (Adipoq) in 31-week-old CD-fed male offspring, and increased mRNA levels of insulin receptor (Insr) and lipoprotein lipase (Lpl) in 31-week-old male offspring on both diets. In liver at 31 weeks, mRNA levels of peroxisome proliferator-activated receptor alpha (Ppara) were elevated in CD-fed male offspring of GDM dams, and male offspring of GDM dams exhibited higher mRNA levels of Insr on both diets. Neither fasting insulin nor glucose tolerance was affected by exposure to GDM. Our findings show that GDM comprising glucose intolerance only during pregnancy programs increased adiposity in offspring, and suggests increased insulin sensitivity of subcutaneous adipose tissue.

Gestational diabetes mellitus (GDM) is a form of heightened insulin resistance triggered during gestation. This study examines how insulin resistance alters placental long-chain polyunsaturated fatty acid (LCPUFA) transport and metabolism in a rat model of lean GDM. Pregnant Sprague Dawley rats were administered with S961, an insulin receptor antagonist (30 nmol/kg s.c. daily), or vehicle from gestational day (GD) 7 to 20. Daily maternal body weight, food, and water intake were measured. Blood pressure assessment and glucose tolerance test were done on GD20. Fetal plasma and placenta were collected on GD20 and processed for fatty acid measurement using LC-mass spectrometry. The expression of fatty acid metabolism-related genes in the placenta was assessed using RT2 Profiler PCR arrays. The results were validated by qRT-PCR. Blockade of insulin receptors with S961 in pregnant rats resulted in glucose intolerance with increased fasting glucose and insulin levels. Maternal body weight gain and food and water intake were not affected; however, S961 significantly increased maternal blood pressure and heart rate. The placenta n3 and n6 LCPUFA concentrations were significantly decreased by 8% and 11%, respectively, but their levels in the fetal plasma were increased by 15% and 4%. RT2 profiler arrays revealed that placental expressions of 10 genes related to fatty acid β-oxidation (Acaa1a, Acadm, Acot2, Acox2, Acsbg1, Acsl4, Acsm5, Cpt1b, Eci2, Ehhadh) and 3 genes related to fatty acid transport pathway (Fabp2, Fabp3, Slc27a3) were significantly upregulated. In summary, lack of insulin action increased the expression of genes related to placental fatty acid β-oxidation and transport with an increased transfer of LCPUFA to the fetus. The increased lipid levels routed toward the fetus may lead to fat adiposity and later-life metabolic dysfunction.

ATP5me alleviates high glucose-induced myocardial cell injury

OBJECTIVEBoth gestational diabetes mellitus (GDM) and mild glucose intolerance in pregnancy identify women at increased risk of future type 2 diabetes. In this context, we queried whether metabolic changes that occur in the 1st year postpartum vary in relation to gestational glucose tolerance status.RESEARCH DESIGN AND METHODSThree-hundred-and-ninety-two women underwent glucose challenge test (GCT) and oral glucose tolerance test (OGTT) in pregnancy followed by repeat OGTT at both 3 months' postpartum and 12 months' postpartum. The antepartum testing defined four gestational glucose tolerance groups: GDM (n = 107); gestational impaired glucose tolerance (GIGT) (n = 75); abnormal GCT with normal glucose tolerance (NGT) on OGTT (abnormal GCT NGT) (n = 137); and normal GCT with NGT on OGTT (normal GCT NGT) (n = 73).RESULTSThe prevalence of dysglycemia progressively increased across the groups from normal GCT NGT to abnormal GCT NGT to GIGT to GDM at both 3 months' postpartum (2.7% to 10.2% to 18.7% to 34.6%, P < 0.0001) and 12 months' postpartum (2.7% to 11.7% to 17.3% to 32.7%, P < 0.0001). Between 3 and 12 months' postpartum, the groups did not differ with respect to changes in waist circumference, weight, or insulin sensitivity. Importantly, however, they exhibited markedly different changes in β-cell function (Insulin Secretion-Sensitivity Index-2 [ISSI-2]) (P = 0.0036), with ISSI-2 declining in both the GDM and GIGT groups. Furthermore, on multiple linear regression analysis, both GDM (t = −3.06, P = 0.0024) and GIGT (t = −2.18, P = 0.03) emerged as independent negative predictors of the change in ISSI-2 between 3 and 12 months' postpartum.CONCLUSIONSWomen with GDM and GIGT exhibit declining β-cell function in the 1st year postpartum that likely contributes to their future diabetic risk.

Background: Gestational diabetes mellitus (GDM) is associated with adverse maternal and neonatal outcomes, however the underlying mechanisms remain elusive. The aim of this study was to find efficient regulator of FGFs in response to the pathogenesis of GDM and explore the role of the FGFs in GDM. Methods: We performed a systematic screening of placental FGFs in GDM patients and further in two different GDM mouse models to investigate their expression changes. Significant changed FGF4 was selected, engineered, purified, and used to treat GDM mice in order to examine whether it can regulate the adverse metabolic phenotypes of the diabetic mice and protect their fetus. Results: We found FGF4 expression was elevated in GDM patients and its level was positively correlated to blood glucose, indicating a physiological relevance of FGF4 with respect to the development of GDM. Recombinant FGF4 (rFGF4) treatment could effectively normalize the adverse metabolic phenotypes in high fat diet induced GDM mice but not in STZ induced GDM mice. However, rFGF4 was highly effective in reduce of neural tube defects (NTDs) of embryos in both the two GDM models. Mechanistically, rFGF4 treatment inhibits pro-inflammatory signaling cascades and neuroepithelial cell apoptosis of both GDM models, which was independent of glucose regulation. Conclusions/interpretation: Our study provides novel insight into the important roles of placental FGF4 and suggests that it may serve as a promising diagnostic factor and therapeutic target for GDM.

Background: Women with gestational diabetes mellitus (GDM) are more likely to develop cardiovascular disease (CVD) within 3 to 10 years following pregnancy. Endothelial dysfunction is a mechanism implicated in both hyperglycemia and CVDs, and it may constitute the missing link in this interaction. One reason for the lack of progress into the cardiovascular complications of GDM is the need for appropriate preclinical models that mimic human GDM. Also, the exact mechanisms mediating increased future cardiovascular risk in maternal with pregnancy-induced diabetes is unclear. Aim: To determine the mechanisms underlying cardiovascular disease in hormonal model of GDM. Methods: Sixteen week-old C57BL/6J female mice were treated with insulin receptor antagonist (S961) or saline (n=4) from the second trimester of pregnancy until delivery to develop a model of GDM. Glucose tolerance test was determined by glucometer and fasting insulin by colorimetry. Cardiac structure and function were measured by echocardiography (VEVO 3100) and pulse wave velocity was measured by Pulse Wave Doppler. Exercise tolerance test was performed on treadmill. Plasma endothelin-1 and nitrite were measured by ELISA and colorimetric assay. Aortic SIRT-1 was determined by western blot and aortic vascular reactivity was determined by wire myograph. Results: S961-induced GDM mice exhibit hyperglycemia (169.2 ± 3.6 vs. 105.5 ± 10.8mg/dL, P&lt;0.004) and hyperinsulinemia (1.9 ± 0.2 vs. 0.8 ± 0.1ng/ml, p&lt;0.01) which mimics the condition observed in human GDM. Interestingly, S961-induced GDM mice went on to develop systolic and diastolic dysfunction, vascular stiffness (3.7 ± 0.1 vs. 3.1 ± 0.08m/s, p&lt;0.005), exercise intolerance and increased thickness of the cardiac wall at 10 weeks post-delivery. Plasma ET-1 was elevated in our model during pregnancy (28.1 ± 1.7 vs. 5.2 ± 0.2pg/ml, p&lt;0.002) and at 10 weeks post-delivery (19.9 ± 2.9 vs. 6.7 ± 0.7pg/ml, p&lt;0.05). Circulating NO and aortic expression of sirtuin-1 (SIRT 1), that is involved in endothelial longevity is reduced in GDM mice. Additionally, vascular relaxation to acetylcholine was attenuated in S961-induced GDM mice. Conclusion: We have developed a novel mouse model of GDM similar to that observed in pregnant women by treatment with S961. Moreover, S961 treated mice develop cardiac dysfunction and vascular stiffness at 10 weeks post-delivery. Alterations in ET-1, SIRT 1, and NO levels may be responsible for the development of CVD in this model.

Gestational diabetes mellitus (GDM) is a metabolic disease that occurs during pregnancy. Herein, we investigate G protein-coupled receptor 1 (GPR1) in mediating GDM through the phosphorylation of serine/threonine kinase (AKT) pathway. Thirty pregnant SD rats were grouped into: normal pregnancy control group (NC), GDM model group, and GDM model + high-dose GPR1 antagonist treatment (GDM + Ari) group. GDM model was established, and the GDM + Ari group adopted GPR1 antagonist aripiprazole. The blood glucose level, insulin level, and insulin resistance (IR) were detected. The expression and phosphorylation of GPR1, AKT, and extracellular signal-regulated kinase (ERK) in placental tissue were detected using reverse transcription-polymerase chain reaction (RT-PCR) and western blotting (WB). The serum insulin concentration, glucose concentration, and glycated hemoglobin concentration during pregnancy in GDM group SD rats were significantly higher than those in the NC group (P < 0.05). The expression and phosphorylation levels of GPR1, AKT, and ERK in the placental tissue of SD pregnant rats in the GDM group were significantly lower than those in the NC group. Furthermore, compared with the GDM group, the expression of GPR1, AKT, and ERK in placental tissue was significantly reduced in the GDM + Ari group, while simultaneously enhancing the blood glucose level and IR level. In addition, the survival number, body weight, and malformation rate of the offspring of the GDM + Ari group were significantly improved, and there was no significant effect on the number of offspring. The expressions of GPR1, AKT, and ERK in placental tissue exhibited a significant decrease, while the glucose level and IR were observed to increase in the GDM + Ari group. Enhancing the expression of GPR1 may activate AKT phosphorylation to alleviate GDM. GPR1 could potentially serve as a novel target for diabetes treatment, offering new insights into managing GDM.

Gestational diabetes mellitus (GDM) is a common obstetric complication. Half of women who have GDM will go on to develop type 2 diabetes. Understanding the mechanisms by which this occurs requires an animal model of GDM without ongoing diabetes at conception. C57Bl/6J mice react acutely to a high-fat, high-sucrose (HFHS) challenge. Here, we hypothesized that a periconceptional HFHS challenge will induce glucose intolerance during gestation. C57Bl/6J female mice were placed on an HFHS either 1 or 3 weeks prior to mating and throughout pregnancy. Intraperitoneal glucose tolerance tests, insulin measurements, and histological analysis of pancreatic islets were used to assess the impact of acute HFHS. C57Bl/6J females fed HFHS beginning 1 week prior to pregnancy became severely glucose intolerant, with reduced insulin response to glucose, and decreased pancreatic islet expansion during pregnancy compared to control mice. These GDM characteristics did not occur when the HFHS diet was started 3 weeks prior to mating, suggesting the importance of acute metabolic stress. Additionally, HFHS feeding resulted in only mild insulin resistance in nonpregnant females. When the diet was discontinued at parturition, symptoms resolved within 3 weeks. However, mice that experienced glucose intolerance in pregnancy became glucose intolerant more readily in response to a HFHS challenge later in life than congenic females that experienced a normal pregnancy, or that were fed the same diet outside of pregnancy. Thus, acute HFHS challenge in C57Bl/6 mice results in a novel, nonobese, animal model that recapitulates the long-term risk of developing type 2 diabetes following GDM.

Women with prior gestational diabetes mellitus (GDM) have higher incidence of age-associated diseases, including type 2 diabetes, CVD and cognitive impairment. Human studies cannot readily determine whether GDM causes these conditions or the underlying mechanisms. Here we used a well-validated rat model of GDM to address these questions. Rats with beta cell-specific expression of human amylin, a pancreatic hormone, were used as a GDM model. Five-month-old female rats were randomly assigned to no-pregnancy, one-pregnancy and two-pregnancies experimental groups. GTTs and transthoracic echocardiography were performed at baseline and during the postpartum period. At 18 months of age, the novel object recognition test was administered, followed by euthanasia and organ collection. All female rats developed glucose intolerance and showed cardiac remodelling and impaired left ventricular relaxation with ageing. Glucose intolerance was exacerbated in rats with prior GDM pregnancies compared with nulliparous rats, with significant differences starting at 9 months of age. However, blood glucose levels were comparable in the three groups during the course of the study. Rats with two GDM-complicated pregnancies had increased left ventricular mass compared with the other groups following the second pregnancy and until the end of the study. At 18 months of age, rats with prior GDM pregnancies presented aggravated demyelination, particularly in the hippocampus and mid-brain region, oxidative stress and neuroinflammation, and had a lower recognition index in the novel object recognition test compared with nulliparous rats. Higher parity exacerbated these effects. Shorter telomeres and reduced mitochondrial DNA content, two hallmarks of biological ageing, were found in the brain, heart and pancreas of rats with prior GDM. These findings support the concept that GDM is a sex-specific risk factor for ageing-related diseases, and point to accelerated cellular ageing as a contributing mechanism. Cardiac echocardiography and GTT data are available at Dataverse under the identifier https://doi.org/10.7910/DVN/R2HITG.

Women with gestational diabetes mellitus and milder gestational impaired glucose intolerance have elevated future risks of type 2 diabetes and cardiovascular disease. However, it is unclear whether they show postpartum evidence of vascular injury/dysfunction, an early event in the natural history of cardiovascular disease. In total, 337 women underwent a glucose challenge test and oral glucose tolerance test in pregnancy, yielding four gestational glucose tolerance groups: gestational diabetes mellitus, gestational impaired glucose intolerance, abnormal glucose challenge test with normal glucose tolerance on the oral glucose tolerance test and normal glucose challenge test with normal glucose tolerance. At 3 years postpartum, they underwent repeat oral glucose tolerance test (on which 69 women had pre-diabetes/diabetes) and measurement of the following serum markers of vascular injury/dysfunction: thrombomodulin, E-selectin, P-selectin, intercellular adhesion molecule-3 and vascular cell adhesion molecule-1. At 3 years postpartum, mean adjusted vascular cell adhesion molecule-1 was the only vascular marker that differed across the previous gestational glucose tolerance groups. On multiple linear regression analysis, each strata of gestational dysglycaemia was an independent predictor of lower vascular cell adhesion molecule-1 at 3 years postpartum (gestational diabetes mellitus: p = 0.005; gestational impaired glucose intolerance: p = 0.003; abnormal glucose challenge test normal glucose tolerance: p = 0.0008), as was current pre-diabetes/diabetes ( p = 0.01). Dysregulation of vascular cell adhesion molecule-1 may be an early event in the natural history of cardiovascular disease in women with recent glucose intolerance in pregnancy.

Gestational diabetes mellitus (GDM) is characterized by the onset of abnormal glucose metabolism during pregnancy. This study aims to examine the expression patterns and functional significance of miR-484 in GDM. The levels of miR-484 in GDM patients were compared to those in normal pregnant women through RT-qPCR. Subsequently, the diagnostic and predictive capacity of miR-484 for GDM was assessed utilizing Receiver Operating Characteristic (ROC) curve. In the next phase, the effects of miR-484 on blood glucose levels and insulin resistance in GDM mice were studied by establishing a GDM mouse model. Finally, pancreatic tissues were isolated to elucidate the influence of miR-484 on inflammation processes and oxidative stress. Elevated levels of miR-484 have been observed in GDM patients, demonstrating a positive correlation with blood glucose levels. ROC curveanalysis indicated that miR-484 possesses substantial diagnostic and predictive capabilities for GDM, with an AUC of 0.835, asensitivity of 80.95%, and aspecificity of 82.00%. Furthermore, in GDM models, the downregulation of miR-484 significantly mitigated the adverse effects associated with GDM, leading to notable reductions in blood glucose levels and insulin resistance. Following the down-regulation of miR-484, a notable reduction in the levels of IL-1β, TNF-α, IL-6, and MDA in the pancreas was alsoobserved. Concurrently, there was a significant increase in the levels of SOD and CAT. miR-484 might act as a biomarker for the early-stage recognition of GDM. Down-regulating this molecule is beneficial for lowering blood glucose, insulin resistance, and pancreatic inflammation or oxidative stress.

Pre-gravid physical activity has been associated with a reduced risk of gestational diabetes mellitus (GDM), although neither the types of exercise nor the physiologic mechanisms underlying this protective effect have been well-studied. Thus, we sought to study the relationships between types of pre-gravid physical activity and metabolic parameters in pregnancy, including glucose tolerance, insulin sensitivity and beta-cell function. A total of 851 women underwent a glucose challenge test (GCT) and a 3-h oral glucose tolerance test (OGTT) in late pregnancy, yielding four glucose tolerance groups: (i) GDM; (ii) gestational impaired glucose tolerance (GIGT); (iii) abnormal GCT with normal glucose tolerance on OGTT (abnormal GCT NGT); and (iv) normal GCT with NGT on OGTT (normal GCT NGT). Pre-gravid physical activity was assessed using the Baecke questionnaire, which measures (i) total physical activity and (ii) its three component domains: work, nonsport leisure-time, and vigorous/sports activity. Glucose tolerance status improved across increasing quartiles of pre-gravid total physical activity (P = 0.0244). Whereas neither work nor nonsport leisure-time activity differed between glucose tolerance groups, pre-gravid vigorous/sports activity was significantly higher in women with normal GCT NGT compared to women with (i) abnormal GCT NGT (P = 0.0018) (ii) GIGT (P = 0.0025), and (iii) GDM (P = 0.0044). In particular, vigorous/sports activity correlated with insulin sensitivity (measured by IS(OGTT)) (r = 0.21, P < 0.0001). Furthermore, on multiple linear regression analysis, pre-gravid vigorous/sports activity emerged as a significant independent predictor of IS(OGTT) in pregnancy (t = 4.97, P < 0.0001). Pre-gravid vigorous/sports activity is associated with a reduced risk of glucose intolerance in pregnancy, an effect likely mediated by enhanced insulin sensitivity.