Physiological changes in insulin resistance in human pregnancy: longitudinal study with the hyperinsulinaemic euglycaemic clamp technique

Oral Glucose Tolerance Test Performed after 28 Gestational Weeks and Risk for Future Diabetes-A 5-Year Cohort Study

Gestational diabetes mellitus (GDM) is diagnosed by an oral glucose tolerance test (oGTT), preferably performed at 24 + 0-28 + 6 gestational weeks, and is considered a risk factor for type 2 diabetes (T2DM). In this study, we aimed to evaluate the risk of T2DM associated with abnormal oGTT performed after 28 weeks. We conducted a retrospective cohort study that included parturients with available glucose levels during pregnancy and up to 5 years of follow-up after pregnancy. Data were extracted from the computerized laboratory system of Meuhedet HMO and cross-tabulated with the Israeli National Registry of Diabetes (INRD). The women were stratified into two groups: late oGTT (performed after 28 + 6 weeks) and on-time oGTT (performed at 24 + 0-28 + 6 weeks). The incidence of T2DM was evaluated and compared using univariate analysis followed by survival analysis adjusted to confounders. Overall, 78,326 parturients entered the analysis. Of them, 6195 (7.9%) performed on-time oGTT and 5288 (6.8%) performed late oGTT. The rest-66,846 (85.3%)-had normal glucose tolerance. Women who performed late oGTT had lower rates of GDM and T2DM. However, once GDM was diagnosed, regardless of oGTT timing, the risk of T2DM was increased (2.93 (1.69-5.1) vs. 3.64 (2.44-5.44), aHR (95% CI), late vs. on-time oGTT, p < 0.001 for both). Unlike in oGTT performed on time, one single abnormal value in late oGTT was not associated with an increased risk for T2DM.

Association Between Plasma Asprosin Levels and Gestational Diabetes Mellitus

Purpose

This study sought to investigate whether asprosin can be used in the diagnosis of GDM or for diagnostic purposes in high-risk pregnancies, along with a review of other parameters that may be associated with serum asprosin levels.

Patients and Methods

The study investigated the association between gestational diabetes mellitus (GDM) and asprosin levels. A total of 93 participants; 30 patients with GDM, 33 healthy pregnant women with normal glucose tolerance (NGT), and 30 healthy non-diabetic women (control group) at the Endocrinology and Metabolic Diseases outpatient clinic of a tertiary care university hospital were enrolled in the study. Patients with GDM and NGT were examined in terms of GDM between the 24th and 28th week of pregnancy (2nd trimester). Patient data were collected during routine examinations, and asprosin levels were measured using the ELISA method. All participants underwent testing for measurements of serum hemoglobin, insulin, C-peptide, fasting plasma glucose, and glycated hemoglobin (HbA1c) levels following a fasting period of at least eight hours.

Results

Asprosin levels were higher in pregnant women with NGT and with GDM versus controls (Control-NGT asprosin, p = 0.001; Control-GDM asprosin, p = 0.001). Pregnant women with GDM had higher asprosin levels than those with NGT (p = 0.001). In detecting GDM in pregnant women, an asprosin cutoff value of >31.709 ng/mL yielded a sensitivity of 93.3%, specificity of 90.9%, positive predictive value of 90.3%, and negative predictive value of 93.75% (p < 0.001).

Conclusion

Serum asprosin levels can potentially be used as a marker in the diagnosis of GDM.

Effect of Vitamin D Supplementation on Serum 25-Hydroxyvitamin D and Homeostatic Model of Insulin Resistance Levels in Healthy Pregnancy: A Systematic Review and Meta-Analysis

Background

Progressive insulin resistance is a physiological condition during pregnancy that can lead to gestational diabetes. Given the association between low blood vitamin D levels and insulin resistance, the present meta-analysis evaluated the effect of vitamin D supplementation on serum 25-hydroxyvitamin D (25[OH]D) and the homeostatic model of insulin resistance (HOMA-IR) levels in non-diabetic pregnant women.

Methods

A comprehensive literature search was conducted using electronic databases and gateways such as Cochrane Library, Medline, Google Scholar, Science Direct, Web of Sciences, Embase, and Scopus. Articles up to 2020 in both English and Persian were included in the study. The effect of vitamin D supplementation on 25(OH)D and HOMA-IR was determined based on the differences in mean changes from baseline to post-intervention. Weighted mean and 95% confidence intervals (CI) were pooled using a random-effects model. Data were analyzed using STATA software.

Results

Four studies, including six trials with 380 participants, reported that vitamin D supplementation increased 25(OH)D (mean change: 13.72, 95% CI: 7.28-20.17) and decreased HOMA-IR (mean change: 1.46, 95% CI: 0.56-2.37) levels compared with the placebo group. A high weekly dose of vitamin D further reduced HOMA-IR levels (adjusted R²=77.99, I² residuals=80.49%, P=0.047). There was no significant association between the dose of vitamin D and 25(OH)D (P=0.974). Intervention duration was not associated with an increase in 25(OH)D (P=0.102), nor with a decrease in HOMA-IR (P=0.623).

Conclusion

Vitamin D supplementation increased 25(OH)D and decreased HOMA-IR levels in non-diabetic pregnant women. Vitamin D in high doses further reduced HOMA-IR, but did not affect 25(OH)D concentrations.

First trimester sex hormone-binding globulin predicts gestational diabetes mellitus in a population of Nigerian women

There has been a steady rise in the disease burden of Gestational Diabetes Mellitus (GDM) in the sub-Saharan African region over time. Diagnostic testing for GDM is currently recommended at 24 - 28 weeks of gestation, leaving a narrow window for intervention before delivery. Hence the need for early prediction and preventive intervention. The performance of first trimester serum sex hormone-binding globulin (SHBG) assay as a predictor of GDM was determined by binary logistic regression. Women with GDM (n = 49) had a significantly lower mean first trimester SHBG level (104.7 ± 61.6 nmol/L) than did those without GDM (n = 180; 265.2 ± 141.5 nmol/L; p < .001). First trimester SHBG was significantly negatively correlated (r_pb = -0.460, p value = <.001) with subsequent development of GDM and an area under receiver operator characteristics (ROC) curve of 0.874 (p < .001). A cut-off value of 158.0 nmol/L predictive of GDM had a diagnostic sensitivity of 81.5%, a specificity of 80.1%, and an overall diagnostic efficiency of 80.3%.IMPACT STATEMENTWhat is already known on this subject? GDM is associated with high risk of various complications and is commonly diagnosed at 24-28 weeks of gestation, leaving a narrow window for intervention. The performance of current maternal clinical and demographic risk factor-based prediction approaches is unreliable. Thus, more favourable prediction approaches need to be developed. Previous studies have suggested that SHBG, a readily assessable marker, has potential to predict GDM; however, these studies have mostly involved Caucasian and other non-African populations.What the results of this study add? SHBG may serve as a reliable first trimester screening tool for GDM development in Nigerian women with singleton pregnancies. This study demonstrates that first trimester SHBG can predict GDM development in sub-Saharan African women despite racial, ethnic and geographical differences.What are the implications of these findings for clinical practice and/or further research? Effective first trimester prediction of GDM using SHBG may enable preventive interventions, thereby mitigating the high burden of the disease in the sub-Saharan African region. It may also provide relevant information that may guide adaptation of current management guidelines to ensure effective management of GDM in the region.

The Impact of a Plant-Based Diet on Gestational Diabetes: A Review

Gestational diabetes mellitus (GDM) represents a challenging pregnancy complication in which women present a state of glucose intolerance. GDM has been associated with various obstetric complications, such as polyhydramnios, preterm delivery, and increased cesarean delivery rate. Moreover, the fetus could suffer from congenital malformation, macrosomia, neonatal respiratory distress syndrome, and intrauterine death. It has been speculated that inflammatory markers such as tumor necrosis factor-alpha (TNF-α), interleukin (IL) 6, and C-reactive protein (CRP) impact on endothelium dysfunction and insulin resistance and contribute to the pathogenesis of GDM. Nutritional patterns enriched with plant-derived foods, such as a low glycemic or Mediterranean diet, might favorably impact on the incidence of GDM. A high intake of vegetables, fibers, and fruits seems to decrease inflammation by enhancing antioxidant compounds. This aspect contributes to improving insulin efficacy and metabolic control and could provide maternal and neonatal health benefits. Our review aims to deepen the understanding of the impact of a plant-based diet on oxidative stress in GDM.

Fetal High-Density Lipoproteins: Current Knowledge on Particle Metabolism, Composition and Function in Health and Disease

Cholesterol and other lipids carried by lipoproteins play an indispensable role in fetal development. Recent evidence suggests that maternally derived high-density lipoprotein (HDL) differs from fetal HDL with respect to its proteome, size, and function. Compared to the HDL of adults, fetal HDL is the major carrier of cholesterol and has a unique composition that implies other physiological functions. Fetal HDL is enriched in apolipoprotein E, which binds with high affinity to the low-density lipoprotein receptor. Thus, it appears that a primary function of fetal HDL is the transport of cholesterol to tissues as is accomplished by low-density lipoproteins in adults. The fetal HDL-associated bioactive sphingolipid sphingosine-1-phosphate shows strong vasoprotective effects at the fetoplacental vasculature. Moreover, lipoprotein-associated phospholipase A2 carried by fetal-HDL exerts anti-oxidative and athero-protective functions on the fetoplacental endothelium. Notably, the mass and activity of HDL-associated paraoxonase 1 are about 5-fold lower in the fetus, accompanied by an attenuation of anti-oxidative activity of fetal HDL. Cholesteryl ester transfer protein activity is reduced in fetal circulation despite similar amounts of the enzyme in maternal and fetal serum. This review summarizes the current knowledge on fetal HDL as a potential vasoprotective lipoprotein during fetal development. We also provide an overview of whether and how the protective functionalities of HDL are impaired in pregnancy-related syndromes such as pre-eclampsia or gestational diabetes mellitus.

Combined analysis of gestational diabetes and maternal weight status from pre-pregnancy through post-delivery in future development of type 2 diabetes

We examined the associations of gestational diabetes mellitus (GDM) and women’s weight status from pre-pregnancy through post-delivery with the risk of developing dysglycaemia [impaired fasting glucose, impaired glucose tolerance, and type 2 diabetes (T2D)] 4–6 years post-delivery. Using Poisson regression with confounder adjustments, we assessed associations of standard categorisations of prospectively ascertained pre-pregnancy overweight and obesity (OWOB), gestational weight gain (GWG) and substantial post-delivery weight retention (PDWR) with post-delivery dysglycaemia (n = 692). Women with GDM had a higher risk of later T2D [relative risk (95% CI) 12.07 (4.55, 32.02)] and dysglycaemia [3.02 (2.19, 4.16)] compared with non-GDM women. Independent of GDM, women with pre-pregnancy OWOB also had a higher risk of post-delivery dysglycaemia. Women with GDM who were OWOB pre-pregnancy and had subsequent PDWR (≥ 5 kg) had 2.38 times (1.29, 4.41) the risk of post-delivery dysglycaemia compared with pre-pregnancy lean GDM women without PDWR. No consistent associations were observed between GWG and later dysglycaemia risk. In conclusion, women with GDM have a higher risk of T2D 4–6 years after the index pregnancy. Pre-pregnancy OWOB and PDWR exacerbate the risk of post-delivery dysglycaemia. Weight management during preconception and post-delivery represent early windows of opportunity for improving long-term health, especially in those with GDM.

Metabolic changes during pregnancy in glucose-intolerant NZO mice: A polygenic model with prediabetic metabolism

Gestational diabetes mellitus (GDM) is a complex metabolic disease involving genetic and environmental factors. Recent studies have underlined its heterogeneity, so it is reasonable to divide patients into subpopulations depending on whether an insulin secretion or sensitivity defect is predominant. Since testing for GDM is usually performed in the second trimester, misinterpretation of prediabetes as gestational diabetes may occur. As with type 2 diabetes (T2DM), rodent models are needed for both GDM and prediabetes, but few do exist. Here, we compared the metabolic changes in pregnant normal NMRI mice with those in New Zealand obese (NZO) mice. Male animals of this strain are an established model of T2DM, whereas female mice of this strain are protected from hyperglycemia and β-cell death. We demonstrate that female NZO mice exhibited impaired glucose tolerance, preconceptional hyperinsulinemia, and hyperglucagonemia without any signs of manifest diabetes. The NZO model showed, compared with the NMRI control strain, a reduced proliferative response of the Langerhans islets during pregnancy (3.7 ± 0.4 vs. 7.2 ± 0.8% Ki-67-positive nuclei, p = .004). However, oral glucose tolerance tests revealed improved stimulation of insulin secretion in both strains. But this adaption was not sufficient to prevent impaired glucose tolerance in NZO mice compared with the NMRI control (p = .0002). Interestingly, glucose-stimulated insulin secretion was blunted in isolated primary NZO islets in perifusion experiments. In summary, the NZO mouse reflects important characteristics of human GDM and prediabetes in pregnancy and serves as a model for subpopulations with early alterations in glucose metabolism and primary insulin secretion defect.

Placensin is a glucogenic hormone secreted by human placenta

FBN1 encodes asprosin, a glucogenic hormone, following furin cleavage of the C-terminus of profibrillin 1. Based on evolutionary conservation between FBN1 and FBN2, together with conserved furin cleavage sites, we identified a peptide hormone placensin encoded by FBN2 based on its high expression in trophoblasts of human placenta. In primary and immortalized murine hepatocytes, placensin stimulates cAMP production, protein kinase A (PKA) activity, and glucose secretion, accompanied by increased expression of gluconeogenesis enzymes. In situ perfusion of liver and in vivo injection with placensin also stimulate glucose secretion. Placensin is secreted by immortalized human trophoblastic HTR-8/SVneo cells, whereas placensin treatment stimulates cAMP-PKA signaling in these cells, accompanied by increases in MMP9 transcripts and activities, thereby promoting cell invasion. In pregnant women, levels of serum placensin increase in a stage-dependent manner. During third trimester, serum placensin levels of patients with gestational diabetes mellitus are increased to a bigger extent compared to healthy pregnant women. Thus, placensin represents a placenta-derived hormone, capable of stimulating glucose secretion and trophoblast invasion.

Adaptations in autonomic nervous system regulation in normal and hypertensive pregnancy

There is an increase in basal sympathetic nerve activity (SNA) during normal pregnancy; this counteracts profound primary vasodilation. However, pregnancy also impairs baroreflex control of heart rate and SNA, contributing to increased mortality secondary to peripartum hemorrhage. Pregnancy-induced hypertensive disorders evoke even greater elevations in SNA, which likely contribute to the hypertension. Information concerning mechanisms is limited. In normal pregnancy, increased angiotensin II acts centrally to support elevated SNA. Hypothalamic sites, including the subfornical organ, paraventricular nucleus, and arcuate nucleus, are likely (but unproven) targets. Moreover, no definitive mechanisms for exaggerated sympathoexcitation in hypertensive pregnancy have been identified. In addition, normal pregnancy increases gamma aminobutyric acid inhibition of the rostral ventrolateral medulla (RVLM), a key brainstem site that transmits excitatory inputs to spinal sympathetic preganglionic neurons. Accumulated evidence supports a major role for locally increased production and actions of the neurosteroid allopregnanolone as one mechanism. A consequence is suppression of baroreflex function, but increased basal SNA indicates that excitatory influences predominate in the RVLM. However, many questions remain regarding other sites and factors that support increased SNA during normal pregnancy and, more importantly, the mechanisms underlying excessive sympathoexcitation in life-threatening hypertensive pregnancy disorders such as preeclampsia.

Clinical importance of the 75-g glucose tolerance test (GTT) in the prediction of large for gestational age (LGA) fetuses in non-diabetic pregnancies

Objective To demonstrate clinical importance of the 75-g glucose tolerance test (GTT) in the prediction of large for gestational age (LGA) fetuses in non-diabetic pregnancies. Methods We retrospectively evaluated 75-g GTT screening results of 356 pregnancies without prompt diagnosis of gestational diabetes mellitus (GDM) between January 2013 and December 2017. Newborns with a birthweight greater than the 90th percentile were evaluated as LGA. Pregnancies with LGA and non-LGA fetuses were compared by demographic and historical factors - maternal age, gravidity, parity, birthweight, birthweek, GTT results and birthweight percentiles - via Student's t-test. Multiple linear regression using the backward elimination method was performed to define the correlation between parameters and LGA (P-value of <0.20 was identified as the threshold). Receiver operator characteristics (ROC) curve analysis was performed for further analysis. Results The cohort was consisted of 45 (12.6%) and 311 (87.4%) pregnancies with LGA and non-LGA fetuses, respectively. Maternal age and 2nd-h GTT results were found to be significantly higher in patients with LGA newborns (P<0.001 and P=0.016, respectively). Fasting glucose levels and GTT 1st-h results were also higher (P=0.112, P=0.065). The coefficient of multiple determination (R2) was 0.055 by multiple linear regression analysis. Accordingly, GTT 2nd-h result and maternal age were statistically significant and contributed to the explanation of LGA, although the R2 value was not that much higher (P=0.016; P=0.001). Maternal age and GTT 2nd-h results were found to be associated with LGA fetuses with area under the curve (AUC) values of 0.662 and 0.608 according to ROC curve analysis. Conclusion Maternal age and 75-g GTT 2nd-h results were significantly higher in gestations with LGA newborns without GDM.

Urinary metabolic variation analysis during pregnancy and application in Gestational Diabetes Mellitus and spontaneous abortion biomarker discovery

Pregnancy is associated with the onset of many adaptation processes that are likely to change over the course of gestation. Understanding normal metabolites’ variation with pregnancy progression is crucial for gaining insights of the key nutrients for normal fetal growth, and for comparative research of pregnancy-related complications. This work presents liquid chromatography-mass spectrum-based urine metabolomics study of 50 health pregnant women at three time points during pregnancy. The influence of maternal physiological factors, including age, BMI, parity and gravity to urine metabolome was explored. Additionally, urine metabolomics was applied for early prediction of two pregnancy complications, gestational diabetes mellitus and spontaneous abortion. Our results suggested that during normal pregnancy progression, pathways of steroid hormone biosynthesis and tyrosine metabolism were significantly regulated. BMI is a factor that should be considered during cross-section analysis. Application analysis discovered potential biomarkers for GDM in the first trimester with AUC of 0.89, and potential biomarkers for SA in the first trimester with AUC of 0.90. In conclusion, our study indicated that urine metabolome could reflect variations during pregnancy progression, and has potential value for pregnancy complications early prediction. The clinical trial number for this study is NCT03246295.

Changes in circulating levels of carboxymethyllysine, soluble receptor for advanced glycation end products (sRAGE), and inflammation markers in women during normal pregnancy

Objective: To determine the circulating levels of insulin, Nε-carboxymethyllysine (CML), soluble receptor for advanced glycation end products (sRAGE), and markers of inflammation and oxidative stress (OS) in maternal and umbilical cord blood in a cohort of healthy women with normal pregnancy.Methods: We conducted an observational longitudinal study in a group of women (n = 31; age range 18-39 years) with healthy pregnancy starting at 30 weeks of gestation and finishing at the time of delivery. We collected weight and height in the participants and their neonates and calculated body mass index (BMI). Blood from each patient was collected at 30th week of pregnancy and at delivery when a sample of cord blood was also obtained. Glucose, lipid profile, CML, sRAGE, malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), highly sensitivity C-reactive protein (hsPCR), and insulin were determined. The study was approved by the University of Guanajuato Institutional Ethics Committee.Results: All pregnancies reached term (mean gestational time 38.9 ± 0.83 weeks) and there were no maternal complications. Mean age was 27.6 years. Lipid profile values were higher in the group compared with our values in nonpregnant women. During pregnancy, levels of insulin increased (p < .0006), CML (p < .0001) and sRAGE (p < .01) decreased, levels of MDA did not change, while those of TNF-α and hsPCR tended to increase. In the neonates, we found lower levels of CML (p < .003), hsPCR (p < .004), and insulin (p < .004) and higher levels of sRAGE (p < .013) and TNF-α (p < .022) compared to their mothers at delivery. In the total group, we found association of CML of the mother at baseline with the CML (p < .0006) and MDA (p < .002) in neonates, while maternal sRAGE at the end of pregnancy was associated with CML (p < .004) of their neonates.Conclusions: Our study confirms that normal pregnancy is accompanied by insulin resistance (IR) and significant increase in lipid profile, and demonstrates that circulating levels of CML and sRAGE decreased significantly at the end of pregnancy. The lack of association between the course of insulin levels and those of CML probably results from the predominant role of placental factors in the pathogenesis of IR in pregnancy. sRAGE levels in the neonates are markedly increased compared to their mothers suggesting a placental origin of this compound which may have a protective effect on the fetus since sRAGE restricts Advanced glycation end product (AGE) effects and may exert anti-inflammatory effects.

Mean Platelet Volume and Gestational Diabetes Mellitus: A Systematic Review and Meta-Analysis

AIM

To evaluate the association between mean platelet volume (MPV) and gestational diabetes mellitus (GDM).

METHODS

A systematic literature search was performed in PubMed, EMBASE, Web of Science, and The Cochrane Library up to 4 September 2017. Pooled standardized mean differences (SMD) and 95% confidence interval (CI) were calculated using a random-effect model.

RESULTS

Nineteen studies comprising 1361 GDM patients and 1911 normal pregnant women were included. MPV was increased in GDM patients when compared with healthy pregnant women (SMD: 0.79; 95% CI: 0.43-1.16; P < 0.001). Subgroup analyses revealed that such trend was consistent in the third-trimester (SMD: 1.35; 95% CI: 0.72-1.98), Turkish (SMD: 0.81; 95% CI: 0.43-1.19), and Italian (SMD: 2.78; 95% CI: 2.22-3.34) patients with GDM and the patients diagnosed based on Carpenter and Coustan criteria (SMD: 1.04; 95% CI: 0.42-1.65). Significantly higher MPV also were observed within cross-sectional studies (SMD: 0.99; 95% CI: 0.49-1.49). Remarkable between-study heterogeneity and potential publication bias were observed in this meta-analysis; however, sensitivity analysis indicated that the results were not unduly influenced by any single study.

CONCLUSIONS

GDM patients are accompanied by increased MPV, strengthening the clinical evidence that MPV may be a predictive marker for GDM.

Triglycerides/Glucose and Triglyceride/High-Density Lipoprotein Cholesterol Indices in Normal and Preeclamptic Pregnancies: A Longitudinal Study

Metabolic changes have been correlated with adverse pregnancy outcomes. The aim of the present study is to determine the TyG and TG/HDL-c indices in a cohort of healthy pregnant (n = 142), preeclamptic (n = 18), and healthy nonpregnant women (n = 56). Preeclamptic women were selected from the same cohort. Pregnant women were followed during three periods of pregnancy and postpartum. The results showed a significant increase in the values of TyG and TG/HDL-c (p < 0.01) as pregnancy progresses, without significant differences between healthy and preeclamptic women. TyG and TG/HDL-c indices are significantly low in nonpregnant and three months' postpartum women when compared with each gestational period studied. TyG and TG/HDL-c indices are positively correlated with HOMA-IR in the early and middle pregnancy (p < 0.05). Multiple linear regression using the TyG and TG/HDL-c indices as dependent variables showed that TyG index was significantly associated with HOMA-IR, gestational age, HDL-c, TC, LDL, fasting insulin, and mean BP (p < 0.001); meanwhile, TG/HDL-c index was only associated with HOMA-IR (p < 0.0242) and gestational age (p < 0.001). In conclusion, the TyG and TG/HDL-c indices could be useful in monitoring insulin resistance during pregnancy.

Postpartum screening practices, progression to abnormal glucose tolerance and its related risk factors in Asian women with a known history of gestational diabetes: A systematic review and meta-analysis

AIMS

Rate of postpartum screening and progression to glucose intolerance (diabetes and/or pre-diabetes) in Asian women with prior GDM and risk factors of diversion to abnormal glucose tolerance were reviewed.

MATERIALS AND METHODS

We searched Pub Med, Cochrane Library, Web of Science, EMBASE, and Ovid data base. About 1300 studies were screened and 27 articles were selected. Meta-analysis using Comprehensive Meta -Analysis software was conducted. All results were reported at the pooled ORs and 95% CI. Quantitative heterogeneity (I²) was assessed. To estimate the variances between studies, the statistical method "tau-squared" was applied. Statistical models like fixed effect or Mantel-Haenszel, and random effect (REM) or Dersimonian-laird were used for the analysis and integration of results.

RESULTS

Rate of glucose testing ranged from 13.1% to 81.9%. Prevalence of pre-diabetes was 3.9%-50.9%. Diabetes was reported in 2.8%-58% of women with history of gestational diabetes based on length of follow-up. Factor associated with postpartum diabetes mellitus included family History of diabetes mellitus, gestational age at diagnosis of GDM, insulin use during pregnancy and pre-pregnancy BMI.

CONCLUSIONS

Rate of postpartum screening in most of the Asian countries population is sub-optimal, in spite of high rate of glucose intolerance in this high risk group of women. Risk factors of progression to pre-diabetes and diabetes are similar to previous reported in developed countries.

Sex hormone binding globulin as a valuable biochemical marker in predicting gestational diabetes mellitus

BACKGROUND

Circulating Sex hormone binding globulin (SHBG) levels are inversely associated with insulin resistance. This study was conducted to compare maternal serum SHBG level between pregnant women with normal glucose tolerance and those with gestational diabetes (GDM) and to investigate the roll of SHBG in GDM diagnosis.

METHODS

This was a case controlled study of 90 pregnant women, 45 women with GDM and 45 matched controls, attending obstetrics clinic at Ohud Hospital, Madina, Saudi Arabia between April 2014 and March 2015. Measurement of serum SHBG levels by Enzyme-linked immunosorbent assay (ELISA) method were done between 24 and 28 weeks of gestation. The best cut-off point of SHBG to diagnose GDM was calculated in receiver operating characteristic curve.

RESULTS

Compared with the control group, SHBG concentrations were significantly lower in the GDM group; median 23 nmol/L (18-30) vs. 78 nmol/L (65-96), p < 0.001). The cut off value 50 nmol/L of the SHBG had 90% sensitivity and 96% specificity to diagnose GDM.

CONCLUSION

Patients with GDM have lower circulating levels of SHBG than normal glucose tolerance pregnant women. Circulating concentrations of SHBG represent a potentially useful new biomarker for prediction of risk of GDM beyond the currently established clinical and demographic risk factors.

Incidence and Contributing Factors of Persistent Hyperglycemia at 6-12 Weeks Postpartum in Iranian Women with Gestational Diabetes: Results from LAGA Cohort Study

Background. A history of gestational diabetes is an important predictor of many metabolic disturbances later in life. Method. Life after gestational diabetes Ahvaz Study (LAGAs) is an ongoing population-based cohort study. Up to February 2016, 176 women with gestational diabetes underwent a 75 g oral glucose tolerance test (OGTT) at 6-12 weeks postpartum in Ahvaz (southwestern of Iran). Gestational diabetes was diagnosed according to the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria and the American Diabetes Association (ADA) criteria applied for diagnosis of postpartum prediabetes and diabetes. Univariate and multivariate regression analysis were done. Results. Overall incidence of early postpartum glucose intolerance was 22.2% (95% CI, 16.3-29.0), 17.6% prediabetes (95% CI, 12.3-24.1) and 4.5% diabetes (95% CI, 2.0-8.8%). Independent risk factors for glucose intolerance were FPG ≥ 100 at the time of OGTT (OR 3.86; 95% CI; 1.60-9.32), earlier diagnosis of GDM (OR 0.92; 95% CI; 0.88-0.97), systolic blood pressure (OR 1.02; 95% CI; 1.002-1.04), and insulin or metformin therapy (OR 3.14; 95% CI; 1.20-8.21). Conclusion. Results determined a relatively high rate of glucose intolerance at 6-12 weeks after GDM pregnancy. Early postpartum screening of type 2 diabetes is needed particularly in women at high risk of type 2 diabetes.

Metabolic profiling of pregnancy: cross-sectional and longitudinal evidence

BACKGROUND

Pregnancy triggers well-known alterations in maternal glucose and lipid balance but its overall effects on systemic metabolism remain incompletely understood.

METHODS

Detailed molecular profiles (87 metabolic measures and 37 cytokines) were measured for up to 4260 women (24-49 years, 322 pregnant) from three population-based cohorts in Finland. Circulating molecular concentrations in pregnant women were compared to those in non-pregnant women. Metabolic profiles were also reassessed for 583 women 6 years later to uncover the longitudinal metabolic changes in response to change in the pregnancy status.

RESULTS

Compared to non-pregnant women, all lipoprotein subclasses and lipids were markedly increased in pregnant women. The most pronounced differences were observed for the intermediate-density, low-density and high-density lipoprotein triglyceride concentrations. Large differences were also seen for many fatty acids and amino acids. Pregnant women also had higher concentrations of low-grade inflammatory marker glycoprotein acetyls, higher concentrations of interleukin-18 and lower concentrations of interleukin-12p70. The changes in metabolic concentrations for women who were not pregnant at baseline but pregnant 6 years later (or vice versa) matched (or were mirror-images of) the cross-sectional association pattern. Cross-sectional results were consistent across the three cohorts and similar longitudinal changes were seen for 653 women in 4-year and 497 women in 10-year follow-up. For multiple metabolic measures, the changes increased in magnitude across the three trimesters.

CONCLUSIONS

Pregnancy initiates substantial metabolic and inflammatory changes in the mothers. Comprehensive characterisation of normal pregnancy is important for gaining understanding of the key nutrients for fetal growth and development. These findings also provide a valuable molecular reference in relation to studies of adverse pregnancy outcomes.

A novel insulin sensitivity index particularly suitable to measure insulin sensitivity during gestation

AIMS

Insulin resistance underlies the etiology of both type 2 diabetes and gestational diabetes. In pregnancy, insulin resistance is also associated with an unfavorable metabolic programming of the fetus, potentially contributing to a higher risk of obesity and type 2 diabetes in the offspring. To assess insulin sensitivity, several methods based on glucose and insulin levels during a 75-g oral glucose tolerance test (OGTT) exist. It is unclear how they perform during pregnancy, where physiologically altered metabolism could introduce a bias.

METHODS

In a cohort comprising 476 non-diabetic subjects undergoing OGTT and hyperinsulinemic-euglycemic clamp (HEC), we used cross-validation to develop an insulin sensitivity index also based on non-esterified fatty acids (NEFA) that could be more robust during pregnancy (NEFA-index). We tested commonly used OGTT-based indexes and the NEFA-index in a different cohort of 42 women during pregnancy and 1 year after delivery.

RESULTS

The Matsuda and OGIS index failed to detect lower insulin sensitivity during pregnancy as compared to the follow-up OGTT 1 year after delivery (p > 0.09). The new NEFA-index incorporating BMI, plasma insulin and NEFA, but not glucose, clearly indicated lower insulin sensitivity during pregnancy (p < 0.0001). In the non-pregnant cohort, this NEFA-index correlated well with the gold-standard HEC-based insulin sensitivity index, and outperformed other tested indexes for the prediction of HEC-measured insulin resistance.

CONCLUSIONS

This insulin/NEFA-based approach is feasible, robust, and could be consistently used to estimate insulin sensitivity also during pregnancy.

Environmental risk factors for pancreatic cancer: an update

Pancreatic cancer (PC) is one of the most aggressive diseases. Only 10 % of all PC cases are thought to be due to genetic factors. Here, we analyzed the most recently published case-control association studies, meta-analyses, and cohort studies with the aim to summarize the main environmental factors that could have a role in PC. Among the most dangerous agents involved in the initiation phase, there are the inhalation of cigarette smoke, and the exposure to mutagenic nitrosamines, organ-chlorinated compounds, heavy metals, and ionizing radiations. Moreover, pancreatitis, high doses of alcohol drinking, the body microbial infections, obesity, diabetes, gallstones and/or cholecystectomy, and the accumulation of asbestos fibers seem to play a crucial role in the progression of the disease. However, some of these agents act both as initiators and promoters in pancreatic acinar cells. Protective agents include dietary flavonoids, marine omega-3, vitamin D, fruit, vegetables, and the habit of regular physical activity. The identification of the factors involved in PC initiation and progression could be of help in establishing novel therapeutic approaches by targeting the molecular signaling pathways responsive to these stimuli. Moreover, the identification of these factors could facilitate the development of strategies for an early diagnosis or measures of risk reduction for high-risk people.

Identifying Key Intervention Opportunities During a Pregnancy Complicated by Diabetes: a Review of Acute Complications of Diabetes During Pregnancy

Diabetes in pregnancy is associated with significant and sometimes devastating acute complications. It is important that all health care providers are aware of possible complications at each stage of pregnancy so that we can prevent these complications whenever possible and reduce morbidity when they do occur. Most complications associated with diabetes during pregnancy have reduced incidence when blood glucose and blood pressure are optimally controlled. Yet, it is always best to try to optimize diabetes and any comorbidities prior to conception.

Normal pregnancy- a state of insulin resistance

BACKGROUND

Purpose of insulin resistance (IR) adapted by mother is to deliver enough quantity of nutrients to the growing fetus. Many maternal hormones and factors play role in causation of IR during pregnancy.

AIM

The study aims at evaluating IR at different trimesters of pregnancy.

MATERIALS AND METHODS

Pregnant women at 1(st), 2(nd) and 3(rd) trimester were grouped into groups I, II and III respectively (n=20 in each group). Healthy non-pregnant women were taken as controls (n=30). Fasting plasma glucose (FPG) and fasting serum insulin (FSI) were measured and IR indices such as fasting glucose to insulin ratio (FGIR), quantitative insulin sensitivity check index (QUICKI), log FSI and log HOMA1-IR were calculated. The student's t-test and one way Analysis of variance (ANOVA) were used for data analysis.

RESULTS

The mean FSI, log FSI and log HOMA 1-IR were significantly higher in 2(nd) and 3(rd) trimesters while QUICKI was significantly lower in 2(nd) and 3(rd) trimesters of pregnancy when compared with controls. Also, mean FGIR was found to be significantly lower in 3rd trimester when compared with controls.

CONCLUSION

As pregnancy advances, IR increases. Increased IR is associated with poor maternal and fetal outcome. Screening of all pregnancy for IR and early intervention may help to reduce the associated complications.

Normal pregnancy- a state of insulin resistance

BACKGROUND

Purpose of insulin resistance (IR) adapted by mother is to deliver enough quantity of nutrients to the growing fetus. Many maternal hormones and factors play role in causation of IR during pregnancy.

AIM

The study aims at evaluating IR at different trimesters of pregnancy.

MATERIALS AND METHODS

Pregnant women at 1(st), 2(nd) and 3(rd) trimester were grouped into groups I, II and III respectively (n=20 in each group). Healthy non-pregnant women were taken as controls (n=30). Fasting plasma glucose (FPG) and fasting serum insulin (FSI) were measured and IR indices such as fasting glucose to insulin ratio (FGIR), quantitative insulin sensitivity check index (QUICKI), log FSI and log HOMA1-IR were calculated. The student's t-test and one way Analysis of variance (ANOVA) were used for data analysis.

RESULTS

The mean FSI, log FSI and log HOMA 1-IR were significantly higher in 2(nd) and 3(rd) trimesters while QUICKI was significantly lower in 2(nd) and 3(rd) trimesters of pregnancy when compared with controls. Also, mean FGIR was found to be significantly lower in 3rd trimester when compared with controls.

CONCLUSION

As pregnancy advances, IR increases. Increased IR is associated with poor maternal and fetal outcome. Screening of all pregnancy for IR and early intervention may help to reduce the associated complications.

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.

Parity and pancreatic cancer risk: evidence from a meta-analysis of twenty epidemiologic studies

Multiple studies have hypothesized parity is associated with pancreatic cancer risk but obtained conflicting results. We conducted a meta-analysis (including a dose-response approach) of current available epidemiologic studies to investigate the association between parity and risk of pancreatic cancer. Ten cohort studies and ten case-control studies including 8205 cases were eligible for inclusion. The combined RR (relative risk) of pancreatic cancer for the parous vs. nulliparous was 0.91 (95% CI, confidence interval = 0.85–0.97, I² = 39.0%, P_h = 0.01). We observed an inverse association between giving birth to two children pancreatic cancer risk with RR of 0.86 (95% CI = 0.80–0.93, I² = 8.7%, P_h = 0.36). And no evidence supported there was non-linear (P = 0.33) or linear relationship (P = 0.14) between number of parity and risk of pancreatic cancer. Findings from this meta-analysis indicate that giving birth to two children has the lowest pancreatic cancer risk, mechanism of this protective effect needs further investigation.

Factors determining insulin requirements in women with type 1 diabetes mellitus during pregnancy: a review

Most women with type 1 diabetes mellitus (T1DM) have increased insulin requirements during pregnancy. However, a minority of women have a fall in insulin requirements. When this occurs in late gestation, it often provokes concern regarding possible compromise of the feto-placental unit. In some centres, this is considered as an indication for delivery, including premature delivery. There are, however, many other factors that affect insulin requirements in pregnancy in women with type 1 diabetes mellitus and the decline in insulin requirements may represent a variant of normal pregnancy. If there is no underlying pathological process, expedited delivery in these women is not warranted and confers increased risks to the newborn. We will explore the factors affecting insulin requirements in gestation in this review. We will also discuss some novel concepts regarding beta-cell function in pregnancy.

Insulin resistance in dairy cows

Glucose is the molecule that drives milk production, and insulin plays a pivotal role in the glucose metabolism of dairy cows. The effect of insulin on the glucose metabolism is regulated by the secretion of insulin by the pancreas and the insulin sensitivity of the skeletal muscles, the adipose tissue, and the liver. Insulin resistance may develop as part of physiologic (pregnancy and lactation) and pathologic processes, which may manifest as decreased insulin sensitivity or decreased insulin responsiveness. A good knowledge of the normal physiology of insulin is needed to measure the in vivo insulin resistance of dairy cows.

The effect of different doses of vitamin D supplementation on insulin resistance during pregnancy

Low serum vitamin D levels are correlated with insulin resistance during pregnancy. We have assessed the effects of different doses of vitamin D on insulin resistance during pregnancy. A randomized clinical trial was done on 120 women with a gestational age of less than 12 weeks. The women were divided into three groups randomly. Group A received 200 IU vitamin D daily, group B 50,000 IU vitamin D monthly and group C 50,000 IU vitamin D every 2 weeks from 12 weeks of pregnancy until delivery. The serum levels of fasting blood sugar (FBS), insulin, calcium and 25-hydroxyvitamin D were measured before and after intervention. We used the homeostatic model assessment of insulin resistance (HOMA-IR) as a surrogate measure of insulin resistance. The mean ± standard deviation of serum 25-hydroxyvitamin D increased in group C from 7.3 ± 5.9 to 34.1 ± 11.5 ng/ml and in group B it increased from 7.3 ± 5.3 to 27.23 ± 10.7 ng/ml, but the level of vitamin D in group A increased from 8.3 ± 7.8 to 17.7 ± 9.3 ng/ml (p < 0.001). The mean differences of insulin and HOMA-IR before and after intervention in groups A and C were significant (p = 0.01, p = 0.02). This study has shown that supplementation of pregnant women with 50 000 IU vitamin D every 2 weeks improved insulin resistance significantly.

THE EVIDENCE FOR LATE-ONSET PRE-ECLAMPSIA AS A MATERNOGENIC DISEASE OF PREGNANCY

It is our opinion that the evidence from epidemiological observations, clinical trials and biological studies is strong enough to support the view of different origin and phenotypes of pre-eclampsia: placental, which usually occurs (but not exclusively) early in pregnancy and is associated with poor early placentation of different severity with subsequent restriction of foetal growth, at different stages of gestation; and maternogenic, which generally occurs late in pregnancy and it is not related to placental insufficiency and foetal growth restriction.

Possible relation between maternal consumption of added sugar and sugar-sweetened beverages and birth weight--time trends in a population

Background

High birth weight (BW) is a risk factor for later obesity. In Norway, mean BW and proportion of large newborns increased from 1989 to 2000 and subsequently decreased to the 1989 level by 2010. The purpose of the study was to explore causes of this temporary increase.

Methods

From a regional prospective database pregnancy and newborn data were extracted for all 33088 singleton pregnancies resulting in live infants born at term without malformations during 1989–2010. Trends in BW, ponderal index and proportion of large newborns were related to individual prenatal exposures, including pre-pregnancy body mass index (PP-BMI) and gestational weight gain (GWG) for the years 2001–2010, and thereafter related ecologically to national population data on consumption of nutrients and physical activity.

Results

For the regional cohort mean (standard deviation) BW increased from 3580 (453) grams in 1989/90 to 3633 (493) grams in 2001/02 (p<0.001), and decreased to 3583 (481) grams in 2009/10 (p<0.001). The proportion with BW>4500 grams increased from 2.6% to 4.8% (p<0.001) and subsequently decreased to 3.3% (p=0.002). The trends remained after adjustment for relevant exposures. For the years 2001/02 to 2009/10 (n= 15240) mean (SD) PP-BMI increased from 24.36 (4.44) to 24.85 (5.02) kg/m² (p<0.001) while GWG decreased from 14.79 (5.85) to 13.86 (5.79) kg (p<0.001). The estimated net effect of changes in PP-BMI, GWG and other known exposures was a 6 grams reduction in BW from 2001/02 to 2009/10, leaving 44 grams reduction unexplained. National consumption of major nutrients did not change, but consumption of sucrose, in large part as sugar-sweetened beverages (SSB) changed in parallel to the BW trends.

Conclusion

The temporary increase in BW and large babies in the regional cohort was identical to that reported for Norway. Individual level data on known pregnancy related predictors for BW could not explain these changes, but the parallel time trend in national consumption of sucrose, in particular as SSB, may lend support to a hypothesis that intake of sugar may have a direct effect on BW and infant body proportions independent of effects through PP-BMI and GWG.

Association of Insulin Resistance with Serum Interleukin-6 and TNF-α Levels During Normal Pregnancy

Overview:

The purpose of this study was to evaluate the role of Tumor Necrosis Factor-α (TNF-α) in insulin resistance (IR) during normal pregnancy.

Approach:

This cross sectional study was carried out on 86 healthy pregnant women including 26, 23 and 37 individuals in the 1st, 2nd and 3rd trimesters, respectively, and in 21 healthy non pregnant women. Serum TNF-α concentration was measured by Enzyme Linked Immunosorbent Assay (ELISA) method.

Results:

There were significant differences between serum TNF-α and IL-6 levels in pregnant women as compared with maternal healthy controls. There was significant correlation between gestational age and Body Mass Index (BMI) (r = 0.28, P = 0.01). There was no significant correlation between gestational age and insulin resistance (IR). We also did not find correlations between IR and TNF-α and IR and IL-6 in pregnant women.

Conclusion:

In conclusion, our findings suggest that TNF-α and IL-6 are not greatly contributed to pregnancy induced insulin resistance in normal pregnancy.

Relationship between maternal growth, infant birthweight and nutrient partitioning in teenage pregnancies

OBJECTIVE

Teenagers are susceptible to delivering small-for-gestational-age (SGA) infants. Previous studies suggest that maternal growth may contribute, as a result of preferential nutrient partitioning to the mother. We investigated the impact of maternal growth on birthweight in pregnant teenagers in the UK, and examined endocrine mediators of nutrient partitioning.

DESIGN

A prospective observational multicentre study, About Teenage Eating, conducted between 2004 and 2007.

SETTING

Four hospitals in socially-deprived areas of Manchester and London.

POPULATION

A total of 500 pregnant adolescents (14-18 years of age) with a singleton pregnancy were recruited at 10-21 weeks of gestation, with follow-up studies on 368 subjects. A cohort of 80 pregnant adults (25-40 years of age) provided a control group for determining growth.

METHODS

Skeletal growth, weight gain and skinfold thickness were measured from first to third trimester, together with maternal levels of micronutrients and metabolic hormones: insulin-like growth factor (IGF) system and leptin. Dietary analyses were performed.

MAIN OUTCOME MEASURE

SGA birth.

RESULTS

Maternal growth was not associated with SGA birth: growing mothers delivered more large-for-gestational-age infants (OR 2.51; P < 0.05). Growers had greater weight gain (P < 0.001), fat accrual (P < 0.001) and red cell folate concentrations (P < 0.01) than non-growers. Maternal IGF-I (P < 0.01) and leptin (P < 0.001) were positively associated with maternal and fetal growth, whereas IGF-I (P < 0.001) was negatively associated. Teenagers that were underweight at booking or with low weight gain were at greater risk of SGA birth.

CONCLUSIONS

Maternal growth was not detrimental to fetal growth in this UK population of teenagers. Greater weight gain and higher concentrations of IGF-I in growing teenagers may provide anabolic drive for maternal and fetal growth.

Insulin resistance: the possible link between gestational diabetes mellitus and hypertensive disorders of pregnancy

Gestational hypertension, preeclampsia, and diabetes are all associated with increased risks of poor maternal and perinatal outcomes. Pregnant women with gestational diabetes have been shown in population studies to have increased risk of pregnancy-associated hypertension compared with nondiabetic women. Moreover, pregnant patients with hypertension are at increased risk for developing gestational diabetes mellitus. It has been hypothesized that this association could be due, at least in part, to insulin resistance. Although insulin resistance is a physiologic phenomenon in normal pregnancy, in predisposed individuals this could lead to hyperinsulinemia with the development of gestational hypertension, gestational diabetes mellitus, or both.

Lactation and changes in maternal metabolic risk factors

OBJECTIVE

To examine the relationship between duration of lactation and changes in maternal metabolic risk factors.

METHODS

This 3-year prospective study examined changes in metabolic risk factors among lactating women from preconception to postweaning and among nonlactating women from preconception to postdelivery, in comparison with nongravid women. Of 1,051 (490 black, 561 white) women who attended two consecutive study visits in years 7 (1992-1993) and 10 (1995-1996), 942 were nongravid and 109 had one interim birth. Of parous women, 48 (45%) did not lactate, and 61 (55%) lactated and weaned before year 10. The lactated and weaned women were subdivided by duration of lactation into less than 3 months and 3 months or more. Multiple linear regression models estimated mean 3-year changes in metabolic risk factors adjusted for age, race, parity, education, and behavioral covariates.

RESULTS

Both parous women who did not lactate and parous women who lactated and weaned gained more weight (+5.6, +4.4 kg) and waist girth (+5.3, +4.9 cm) than nongravid women over the 3-year interval; P<.001. Low-density lipoprotein cholesterol (+6.7 mg/dL, P<.05) and fasting insulin (+2.6 microunits, P=.06) increased more for parous women who did not lactate than for nongravid and parous women who lactated and weaned. High-density lipoprotein cholesterol decrements for both parous women who did not lactate and parous women who lactated and weaned were 4.0 mg/dL greater than for nongravid women (P<.001). Among parous, lactated and weaned women, lactation for 3 months or longer was associated with a smaller decrement in high-density lipoprotein cholesterol (-1.3 mg/dL versus -7.3 mg/dL for less than 3 months; P<.01).

CONCLUSION

Lactation may attenuate unfavorable metabolic risk factor changes that occur with pregnancy, with effects apparent after weaning. As a modifiable behavior, lactation may affect women's future risk of cardiovascular and metabolic diseases.

LEVEL OF EVIDENCE

II.

Inflammation and pre-eclampsia

Pre-eclampsia is a common and potentially dangerous disorder of human pregnancy. The maternal syndrome of hypertension, proteinuria and oedema is part of a severe systemic inflammatory response that includes leukocyte and endothelial cell activation. Although the origins of pre-eclampsia remain unclear, a major cause is the failure to develop an adequate blood supply to the placenta, leading to placental oxidative stress. This results in the excess release of placental factors, such as syncytiotrophoblast debris or soluble fms-like tyrosine kinase-1 (sFlt-1), the soluble receptor for vascular endothelial growth factor (VEGF), into the maternal circulation, where they trigger an inflammatory response and endothelial dysfunction. Alternatively, pre-eclampsia can develop in the presence of a normal placenta in women that are susceptible to systemic inflammation, such as with chronic cardiovascular disease or diabetes. While clinical management of pre-eclampsia does not currently include anti-inflammatory agents, current research is focusing on ways to reduce inflammation and oxidative stress.

Decreased maternal lipolysis in intrauterine growth restriction in the third trimester

OBJECTIVE

Intrauterine growth restriction (IUGR) is a common complication of pregnancy. There are many possible aetiologic factors of maternal, placental and/or fetal origin. Often there is no known explanation. The aim of this study was to investigate whether a reduction in maternal energy substrate production could be one of the factors involved in IUGR.

DESIGN

Measurement of maternal energy substrate production and glucoregulatory hormones in women with growth-restricted fetuses.

SETTINGS

University Hospital, Uppsala, Sweden.

POPULATION

Ten healthy pregnant women with IUGR were compared with eight recently reported healthy women with normal pregnancies. The women were studied at 35.4+/-1.6 weeks of gestation after an overnight fast.

METHODS

Rates of glycerol and glucose production were analysed by gas chromatography/mass spectrometry following constant-rate infusion of [1,1,2,3,3-(2)H5]glycerol and [6,6-(2)H2]glucose.

MAIN OUTCOME MEASURE

Third trimester glycerol and glucose production.

RESULTS

Glycerol production, reflecting lipolysis, was lower in the women with IUGR than in those with normal pregnancies, 2.36+/-0.58 versus 3.06+/-0.66 micromol kg-1 minute-1 (P=0.033), whereas there was no difference in rate of glucose production (glucose production rate [GPR]), 12.1+/-1.5 versus 13.2+/-1.5 micromol kg-1 minute-1 (P=0.23). Plasma glycerol levels were increased in the women with IUGR (P=0.008).

CONCLUSIONS

Lipolysis is lower in pregnancies complicated by IUGR as compared with normal pregnancies. Increased lipolysis during pregnancy provides substrate for maternal energy metabolism, which spares glucose for the fetus. A reduced maternal production of energy substrate could be one of several factors underlying IUGR. A lack of relationship between insulin levels and either lipolysis or GPR suggests defective regulation of energy substrate production in this group of pregnant women.

Preeclampsia in Lean Normotensive Normotolerant Pregnant Women Can Be Predicted by Simple Insulin Sensitivity Indexes

Certain similarities between preeclampsia and insulin resistance syndrome suggest a possible link between the 2 diseases. The aim of our study was to evaluate 3 insulin sensitivity (IS) indexes (fasting homeostasis model assessment IS [ISHOMA], quantitative insulin sensitivity check index [ISQUICKI], and oral glucose IS [OGIS]) early and late in pregnancy in a large number of normotensive pregnant women with a normal glucose tolerance and to test the ability of these indexes to predict the risk of subsequent preeclampsia. In all, 829 pregnant women were tested with a 75-g, 2-hour oral glucose load in 2 periods of pregnancy: early (16 to 20 weeks) and late (26 to 30 weeks). In early and late pregnancy, respectively, IS(HOMA) was 1.23+/-0.05 and 1.44+/-0.05 (P<0.01), IS(QUICKI) was 0.40+/-0.002 and 0.38+/-0.002 (P<0.01), and OGIS was 457+/-2.4 mL min(-1) m(-2) and 445+/-2.2 (P<0.001), all confirming the reduction in insulin sensitivity during pregnancy. Preeclampsia developed in 6.4% of the pregnant women and correlated positively with the 75th centile of IS(HOMA) (P=0.001), with a sensitivity of 79% in the early and 83% in the late period and a specificity of 97% in both. IS(QUICKI) <25th centile was also related with preeclampsia (P=0.001), with a sensitivity of 85% in the early and 88% in the late period and a specificity of 97% in both. Judging from our findings, ISHOMA and ISQUICKI are simple tests that can pinpoint impaired insulin sensitivity early in the pregnancy. Given their high sensitivity and specificity, these indexes could be useful in predicting the development of preeclampsia in early pregnancy, before the disease become clinically evident.

Increased lipolysis in non-obese pregnant women studied in the third trimester

BACKGROUND

During pregnancy, metabolic adaptation takes place in the mother to provide for the supply of substrates to the growing fetus.

OBJECTIVE

To determine rates and endocrine regulation of lipolysis and glucose production (GPR) in late pregnancy.

DESIGN

Energy substrate production was measured in healthy pregnant women by use of stable isotope-labelled compounds.

SETTING

University Hospital, Uppsala, Sweden.

SAMPLE

Eight healthy non-obese, non-smoking women with normal pregnancies were studied at 33-36 weeks of gestation after an overnight (12-14 hours) fast.

METHODS

Rates of glycerol and glucose production were analysed by gas chromatography/mass spectrometry following constant rate infusion of [1,1,2,3,3-(2)H(5)]-glycerol and [6,6-(2)H(2)]-glucose.

MAIN OUTCOME MEASURE

Glycerol and glucose production in the third trimester.

RESULTS

The mean rate of glycerol production, reflecting lipolysis, was 3.06 (0.66) and the mean GPR was 13.2 (1.5) micromol kg(-1) minute(-1) [2.38 (0.27) mg kg(-1) minute(-1)]. There was a correlation between rate of glycerol production and GPR (r = 0.75, P = 0.033). Fasting insulin levels correlated inversely with both the rate of glycerol production (r = -0.85, P = 0.008) and GPR (r = -0.78, P= 0.021).

CONCLUSIONS

Our results show that lipolysis is markedly increased during late pregnancy compared with reported data for non-pregnant women. The data also confirm the occurrence of an increased GPR in pregnant women. The finding of a correlation between rate of glycerol production and GPR corroborates the view that lipolysis promotes gluconeogenesis. Although late gestation is associated with insulin resistance, the results show that insulin plays a regulatory role both in lipolysis and glucose production.

Prognosis of premenopausal breast cancer and childbirth prior to diagnosis

PURPOSE

The time interval between last childbirth and subsequent breast cancer diagnosis is emerging as an important prognostic factor for premenopausal women.

PATIENTS AND METHODS

We studied, prospectively, 750 women diagnosed with primary invasive breast cancer before age 45 years who participated in the population-based Australian Breast Cancer Family Study (ABCFS).

RESULTS

Median follow-up time was 4.9 years (range, 0.8 to 10.8 years). Compared with nulliparous women, women who gave birth within 2 years prior to diagnosis were more likely to have axillary node-positive (58% v 41%; P =.01), and estrogen receptor-negative (58% v 39%; P =.005) tumors. The unadjusted hazard ratios for death were 2.3 (95% CI, 1.3 to 3.8; P =.002), 1.7 (95% CI, 1.1 to 2.6; P =.03), and 0.9 (95% CI, 0.6 to 1.5; P =.8) for patients who gave birth less than 2 years, 2 to 5 years, and 5 or more years before diagnosis, respectively. After adjusting for tumor characteristics, these hazard ratios were reduced to 1.9 (95%CI, 1.1 to 3.2; P =.02), 1.3 (95% CI, 0.8 to 2.1; P =.3), and 0.9 (95%CI, 0.5 to 1.4; P =.5). Modeling showed that, compared with nulliparous women, the mortality hazard ratio in parous women was 1.9, decreasing by 8% (95%CI, 4% to 13%; P <.001) for each year between last birth and breast cancer diagnosis.

CONCLUSION

Proximity of last childbirth to subsequent breast cancer diagnosis is a predictor of mortality independent of histopathological tumor characteristics. Clinicians should be aware that women diagnosed with breast cancer within a few years following childbirth may have a worse outcome than that suggested solely by the standard histopathological prognostic factors of their cancer.

Upper abdominal obesity, insulin resistance and breast cancer risk

PURPOSE

A majority of prospective studies show breast cancer risk to be higher in obese postmenopausal women with upper abdominal adiposity than in those with overall adiposity. The evidence is more limited and inconsistent in the case of premenopausal women. The review examines evidence that aberrant insulin signalling may be involved in the promotion of mammary carcinogenesis. The aetiology and concomitants of abdominal visceral obesity are examined.

MECHANISMS

Clinical and experimental evidence suggests that the higher breast cancer risk associated with greater abdominal visceral obesity may be related to aberrant insulin signalling through the insulin receptor substrate 1 pathway, leading to insulin resistance, hyperinsulinaemia and increased concentrations of endogenous oestrogen and androgen. The putative role of aberrant insulin signalling in the promotion of mammary carcinogenesis may help to explain clinical relationships between breast cancer risk and age at menarche, pregnancies and onset of obesity.

CONCLUSION

Overall adiposity in women adversely affects breast cancer risk mainly by greater exposure of mammary epithelial tissue to endogenous oestrogen. Upper abdominal adiposity appears to involve an additional effect related to the presence of insulin resistance. Aetiological factors in the development of hyperinsulinaemic insulin resistance are still uncertain but may involve aberrant susceptibility genes in adipocyte insulin receptors or in the insulin receptor substrate 1 pathway. Epigenetic factors are also likely to contribute, including high free fatty acid levels and obesity. Dietary fatty acids, particularly polyunsaturated fatty acids, are known to regulate adipocyte differentiation through the nuclear peroxisome proliferator-activated receptor gamma, and may also have a role in insulin resistance. These aetiological factors are likely to be relevant to the high risk of postmenopausal breast cancer in industrialised Western populations.

First trimester insulin resistance and subsequent preeclampsia: a prospective study

Insulin resistance is implicated in the pathogenesis of preeclampsia, but prospective data are limited. SHBG, a marker of insulin resistance among nonpregnant individuals, has not been studied in detail during pregnancy. We conducted a prospective, nested, case-control study to test the hypothesis that increased insulin resistance, marked by reduced first trimester SHBG levels, is associated with increased risk of subsequent preeclampsia. First trimester SHBG levels were measured in 45 nulliparous women who subsequently developed preeclampsia (blood pressure, > or =140/90 mm Hg; proteinuria, either > or =2+ by dipstick or > or =300 mg/24 h, after 20 wk gestation) and in 90 randomly selected normotensive nulliparous controls. Compared with controls, women who developed preeclampsia had significantly reduced first trimester SHBG levels (302 +/- 130 vs. 396 +/- 186 nmol/liter; P < 0.01). Every 100 nmol/liter increase in SHBG was associated with a 31% reduced risk of preeclampsia [odds ratio (OR), 0.69; 95% confidence interval (CI), 0.55, 0.88; P < 0.01]. After adjusting for covariates in a multiple logistic regression model, the association between first trimester SHBG and preeclampsia remained significant (per 100 nmol/liter increase; OR, 0.66; 95% CI, 0.47, 0.92; P = 0.01). When subjects were stratified by body mass index (lean: body mass index, < 25 kg/m(2); overweight: body mass index, > or =25 kg/m(2)), overweight women had lower SHBG levels than lean women (286 +/- 156 vs. 410 +/- 166 nmol/liter; P < 0.01), and within each stratum, women with preeclampsia had lower SHBG levels than their respective controls. In a multivariable analysis, the association between SHBG and preeclampsia strengthened among lean women, such that every 100 nmol/liter increase in serum SHBG was associated with a 55% reduction in the risk of preeclampsia (OR, 0.45; 95% CI, 0.27, 0.77; P < 0.01), whereas in overweight women, the association was mitigated (OR, 1.02; 95% CI, 0.62, 1.69; P = 0.9). We conclude that increased early pregnancy insulin resistance is independently associated with subsequent preeclampsia. First trimester SHBG levels may be a useful biomarker for preeclampsia, especially among lean women who otherwise would be perceived to be at low risk.

Insulin sensitivity and fertility

This review sets in context significant recent advances in the understanding of the pathophysiology of polycystic ovary syndrome (PCOS). The occurrence of variable insulin sensitivity in individuals is discussed. Information is presented to demonstrate that prolonged anovulation decreases insulin sensitivity and, conversely, that improvement in insulin sensitivity normalizes ovarian function in PCOS. In addition, a meta-analysis of studies on metformin and troglitazone treatment in PCOS is presented.

High intake of energy, sucrose, and polyunsaturated fatty acids is associated with increased risk of preeclampsia

OBJECTIVE

Preeclampsia is associated with high body mass index, insulin resistance, and hypertriglyceridemia. Our objective was to investigate prospectively whether diet in the first half of pregnancy is associated with the risk for preeclampsia.

STUDY DESIGN

This prospective, population-based, cohort study of pregnant women investigated dietary intake early in the second trimester with a quantitative food frequency questionnaire.

RESULTS

The questionnaire was completed by 3133 women (83%). Preeclampsia developed in 85 women. Adjusted odds ratio (95% CI) for preeclampsia was 3.7 (1.5-8.9) for energy intake of >3350 kcal/d compared with < or =2000 kcal/d. Adjusted odds ratio (95% CI) for preeclampsia was 3.6 (1.3-9.8) for sucrose intake (percent of total energy) of >25% compared with < or =8.5% and 2.6 (1.3-5.4) for polyunsaturated fatty acids intake (percent of total energy) of >7.5% compared with < or =5.2%. Other energy-providing nutrients were not associated with the risk for preeclampsia.

CONCLUSION

The current study suggests that high intakes of energy, sucrose, and polyunsaturated fatty acids independently increase the risk for preeclampsia.