Metabolic Dynamics and Prediction of Gestational Age and Time to Delivery in Pregnant Women.

Metabolism during pregnancy is a dynamic and precisely programmed process, the failure of which can bring devastating consequences to the mother and fetus. To define a high-resolution temporal profile of metabolites during healthy pregnancy, we analyzed the untargeted metabolome of 784 weekly blood samples from 30 pregnant women. Broad changes and a highly choreographed profile were revealed: 4,995 metabolic features (of 9,651 total), 460 annotated compounds (of 687 total), and 34 human metabolic pathways (of 48 total) were significantly changed during pregnancy. Using linear models, we built a metabolic clock with five metabolites that time gestational age in high accordance with ultrasound (R = 0.92). Furthermore, two to three metabolites can identify when labor occurs (time to delivery within two, four, and eight weeks, AUROC ≥ 0.85). Our study represents a weekly characterization of the human pregnancy metabolome, providing a high-resolution landscape for understanding pregnancy with potential clinical utilities.

Hypothalamic vasopressin sex differentiation is observed by embryonic day 15 in mice and is disrupted by the xenoestrogen bisphenol A.

Arginine vasopressin (AVP) neurons of the hypothalamic paraventricular region (AVPPVN) mediate sex-biased social behaviors across most species, including mammals. In mice, neural sex differences are thought to be established during a critical window around birth ( embryonic (E) day 18 to postnatal (P) day 2) whereby circulating testosterone from the fetal testis is converted to estrogen in sex-dimorphic brain regions. Here, we found that AVPPVN neurons are sexually dimorphic by E15.5, prior to this critical window, and that gestational bisphenol A (BPA) exposure permanently masculinized female AVPPVN neuronal numbers, projections, and electrophysiological properties, causing them to display male-like phenotypes into adulthood. Moreover, we showed that nearly twice as many neurons that became AVP+ by P0 were born at E11 in males and BPA-exposed females compared to control females, suggesting that AVPPVN neuronal masculinization occurs between E11 and P0. We further narrowed this sensitive period to around the timing of neurogenesis by demonstrating that exogenous estrogen exposure from E14.5 to E15.5 masculinized female AVPPVN neuronal numbers, whereas a pan-estrogen receptor antagonist exposed from E13.5 to E15.5 blocked masculinization of males. Finally, we showed that restricting BPA exposure to E7.5-E15.5 caused adult females to display increased social dominance over control females, consistent with an acquisition of male-like behaviors. Our study reveals an E11.5 to E15.5 window of estrogen sensitivity impacting AVPPVN sex differentiation, which is impacted by prenatal BPA exposure.

Gestational iron deficiency affects the ratio between interneuron subtypes in the postnatal cerebral cortex in mice.

Gestational iron deficiency (gID) is highly prevalent and associated with an increased risk of intellectual and developmental disabilities in affected individuals that are often defined by a disrupted balance of excitation and inhibition (E/I) in the brain. Using a nutritional mouse model of gID, we previously demonstrated a shift in the E/I balance towards increased inhibition in the brains of gID offspring that was refractory to postnatal iron supplementation. We thus tested whether gID affects embryonic progenitor cells that are fated towards inhibitory interneurons. We quantified relevant cell populations during embryonic inhibitory neuron specification and found an increase in the proliferation of Nkx2.1+ interneuron progenitors in the embryonic medial ganglionic eminence at E14 that was associated with increased Shh signaling in gID animals at E12. When we quantified the number of mature inhibitory interneurons that are known to originate from the MGE, we found a persistent disruption of differentiated interneuron subtypes in early adulthood. Our data identify a cellular target that links gID with a disruption of cortical interneurons which play a major role in the establishment of the E/I balance.

Extracellular vesicles and immune response during pregnancy: A balancing act.

The mechanisms underlying maternal tolerance of the semi- or fully-allogeneic fetus are intensely investigated. Across gestation, feto-placental antigens interact with the maternal immune system locally within the trophoblast-decidual interface and distantly through shed cells and soluble molecules that interact with maternal secondary lymphoid tissues. The discovery of extracellular vesicles (EVs) as local or systemic carriers of antigens and immune-regulatory molecules has added a new dimension to our understanding of immune modulation prior to implantation, during trophoblast invasion, and throughout the course of pregnancy. New data on immune-regulatory molecules, located on EVs or within their cargo, suggest a role for EVs in negotiating immune tolerance during gestation. Lessons from the field of transplant immunology also shed light on possible interactions between feto-placentally derived EVs and maternal lymphoid tissues. These insights illuminate a potential role for EVs in major obstetrical disorders. This review provides updated information on intensely studied, pregnancy-related EVs, their cargo molecules, and patterns of fetal-placental-maternal trafficking, highlighting potential immune pathways that might underlie immune suppression or activation in gestational health and disease. Our summary also underscores the likely need to broaden the definition of the maternal-fetal interface to systemic maternal immune tissues that might interact with circulating EVs.

Effects of gestational hypothyroidism on mouse brain development: Gabaergic systems and oxidative stress.

Hormonal imbalance during pregnancy is a risk factor for neuropsychiatric impairment in the offspring. It has been suggested that hypothyroidism leads to dysfunction of cortical GABAergic interneurons and inhibitory system development that in turn underlies impairment of the central nervous system. Here we investigated how gestational hypothyroidism affected offspring GABAergic system development as well as redox regulation parameters, because of previous links identified between the two. Experimental Gestational Hypothyroidism (EGH) was induced in CD-1 mice with 0.02% methimazole (MMI) in drinking water from embryonic day 9 (E9) until tissue collection at embryonic day 14 (E14) or E18. We examined GABAergic cell distribution and inhibitory system development gene expression as well as redox relevant gene expression and direct measures across all embryos regardless of sex. Intrauterine restriction of maternal thyroid hormones significantly impacted both of these outcomes in brain, as well as altering redox regulation in the placenta. GAD67+ neuronal migration was reduced, accompanied by a disruption in gene expression influencing GABAergic cell migration and cortical inhibitory neural system development. EGH also altered embryonic brain gene expression of Gpx1, Nfe2l2, Cat levels in the dorsal E14 brains. Additionally, EGH resulted in elevated TBARS, Gpx1 and Nfe2l2 in the ventral E18 brains. Furthermore, EGH downregulated placental Gpx1 gene expression at E14 and increased protein oxidation at E18. These findings support the hypothesis that sufficient maternal thyroid hormone supply to the fetus influences central nervous system development, including processes of GABAergic system development and redox equilibrium.

Opportunities in the Postpartum Period to Reduce Cardiovascular Disease Risk After Adverse Pregnancy Outcomes: A Scientific Statement From the American Heart Association.

Adverse pregnancy outcomes are common among pregnant individuals and are associated with long-term risk of cardiovascular disease. Individuals with adverse pregnancy outcomes also have an increased incidence of cardiovascular disease risk factors after delivery. Despite this, evidence-based approaches to managing these patients after pregnancy to reduce cardiovascular disease risk are lacking. In this scientific statement, we review the current evidence on interpregnancy and postpartum preventive strategies, blood pressure management, and lifestyle interventions for optimizing cardiovascular disease using the American Heart Association Life's Essential 8 framework. Clinical, health system, and community-level interventions can be used to engage postpartum individuals and to reach populations who experience the highest burden of adverse pregnancy outcomes and cardiovascular disease. Future trials are needed to improve screening of subclinical cardiovascular disease in individuals with a history of adverse pregnancy outcomes, before the onset of symptomatic disease. Interventions in the fourth trimester, defined as the 12 weeks after delivery, have great potential to improve cardiovascular health across the life course.

Identify gestational diabetes mellitus by deep learning model from cell-free DNA at the early gestation stage.

Gestational diabetes mellitus (GDM) is a common complication of pregnancy, which has significant adverse effects on both the mother and fetus. The incidence of GDM is increasing globally, and early diagnosis is critical for timely treatment and reducing the risk of poor pregnancy outcomes. GDM is usually diagnosed and detected after 24 weeks of gestation, while complications due to GDM can occur much earlier. Copy number variations (CNVs) can be a possible biomarker for GDM diagnosis and screening in the early gestation stage. In this study, we proposed a machine-learning method to screen GDM in the early stage of gestation using cell-free DNA (cfDNA) sequencing data from maternal plasma. Five thousand and eighty-five patients from north regions of Mainland China, including 1942 GDM, were recruited. A non-overlapping sliding window method was applied for CNV coverage screening on low-coverage (~0.2×) sequencing data. The CNV coverage was fed to a convolutional neural network with attention architecture for the binary classification. The model achieved a classification accuracy of 88.14%, precision of 84.07%, recall of 93.04%, F1-score of 88.33% and AUC of 96.49%. The model identified 2190 genes associated with GDM, including DEFA1, DEFA3 and DEFB1. The enriched gene ontology (GO) terms and KEGG pathways showed that many identified genes are associated with diabetes-related pathways. Our study demonstrates the feasibility of using cfDNA sequencing data and machine-learning methods for early diagnosis of GDM, which may aid in early intervention and prevention of adverse pregnancy outcomes.

The role of ncRNA regulatory mechanisms in diseases-case on gestational diabetes.

Non-coding RNAs (ncRNAs) are a class of RNA molecules that do not have the potential to encode proteins. Meanwhile, they can occupy a significant portion of the human genome and participate in gene expression regulation through various mechanisms. Gestational diabetes mellitus (GDM) is a pathologic condition of carbohydrate intolerance that begins or is first detected during pregnancy, making it one of the most common pregnancy complications. Although the exact pathogenesis of GDM remains unclear, several recent studies have shown that ncRNAs play a crucial regulatory role in GDM. Herein, we present a comprehensive review on the multiple mechanisms of ncRNAs in GDM along with their potential role as biomarkers. In addition, we investigate the contribution of deep learning-based models in discovering disease-specific ncRNA biomarkers and elucidate the underlying mechanisms of ncRNA. This might assist community-wide efforts to obtain insights into the regulatory mechanisms of ncRNAs in disease and guide a novel approach for early diagnosis and treatment of disease.

Sex-specific effect of antenatal Zika virus infection on murine fetal growth, placental nutrient transporters, and nutrient sensor signaling pathways.

Maternal Zika virus (ZIKV) infection during pregnancy has been associated with severe intrauterine growth restriction (IUGR), placental damage, metabolism disturbances, and newborn neurological abnormalities. Here, we investigated the impact of maternal ZIKV infection on placental nutrient transporters and nutrient-sensitive pathways. Immunocompetent (C57BL/6) mice were injected with Low (103 PFU-ZIKVPE243) or High (5 × 107 PFU-ZIKVPE243) ZIKV titers at gestational day (GD) 12.5, and tissue was collected at GD18.5 (term). Fetal-placental growth was impaired in male fetuses, which exhibited higher placental expression of the ZIKV infective marker, eukaryotic translation initiation factor 2 (eIF2α), but lower levels of phospho-eIF2α. There were no differences in fetal-placental growth in female fetuses, which exhibited no significant alterations in placental ZIKV infective markers. Furthermore, ZIKV promoted increased expression of glucose transporter type 1 (Slc2a1/Glut1) and decreased levels of glucose-6-phosphate in female placentae, with no differences in amino acid transport potential. In contrast, ZIKV did not impact glucose transporters in male placentae but downregulated sodium-coupled neutral amino acid 2 (Snat2) transporter expression. We also observed sex-dependent differences in the hexosamine biosynthesis pathway (HBP) and O-GlcNAcylation in ZIKV-infected pregnancies, showing that ZIKV can disturb placental nutrient sensing. Our findings highlight molecular alterations in the placenta caused by maternal ZIKV infection, shedding light on nutrient transport, sensing, and availability. Our results also suggest that female and male placentae employ distinct coping mechanisms in response to ZIKV-induced metabolic changes, providing insights into therapeutic approaches for congenital Zika syndrome.

Rheumatoid arthritis and cardiovascular complications during delivery: a United States inpatient analysis.

BACKGROUND AND AIMS: Persons with rheumatoid arthritis (RA) have an increased risk of obstetric-associated complications, as well as long-term cardiovascular (CV) risk. Hence, the aim was to evaluate the association of RA with acute CV complications during delivery admissions. METHODS: Data from the National Inpatient Sample (2004-2019) were queried utilizing ICD-9 or ICD-10 codes to identify delivery hospitalizations and a diagnosis of RA. RESULTS: A total of 12 789 722 delivery hospitalizations were identified, of which 0.1% were among persons with RA (n = 11 979). Individuals with RA, vs. those without, were older (median 31 vs. 28 years, P < .01) and had a higher prevalence of chronic hypertension, chronic diabetes, gestational diabetes mellitus, obesity, and dyslipidaemia (P < .01). After adjustment for age, race/ethnicity, comorbidities, insurance, and income, RA remained an independent risk factor for peripartum CV complications including preeclampsia [adjusted odds ratio (aOR) 1.37 (95% confidence interval 1.27-1.47)], peripartum cardiomyopathy [aOR 2.10 (1.11-3.99)], and arrhythmias [aOR 2.00 (1.68-2.38)] compared with no RA. Likewise, the risk of acute kidney injury and venous thromboembolism was higher with RA. An overall increasing trend of obesity, gestational diabetes mellitus, and acute CV complications was also observed among individuals with RA from 2004-2019. For resource utilization, length of stay and cost of hospitalization were higher for deliveries among persons with RA. CONCLUSIONS: Pregnant persons with RA had higher risk of preeclampsia, peripartum cardiomyopathy, arrhythmias, acute kidney injury, and venous thromboembolism during delivery hospitalizations. Furthermore, cardiometabolic risk factors among pregnant individuals with RA rose over this 15-year period.

Gestational diabetes and future cardiovascular diseases: associations by sex-specific genetic data.

BACKGROUND AND AIMS: Observational studies have highlighted that gestational diabetes mellitus is associated with a higher risk of cardiovascular diseases, but the causality remains unclear. Herein, the causality between genetic predisposition to gestational diabetes mellitus and the risk of cardiovascular diseases was investigated using sex-specific Mendelian randomization analysis. METHODS: Linkage disequilibrium score regression analysis and two-sample Mendelian randomization analysis were applied to infer the genetic correlation and causality, respectively. Mediation analysis was conducted using a two-step Mendelian randomization approach. Sensitivity analyses were performed to differentiate causality from pleiotropy. The genome-wide association study summary statistics for gestational diabetes mellitus were obtained from FinnGen consortium, while for cardiovascular diseases were generated based on individual-level genetic data from the UK Biobank. RESULTS: Linkage disequilibrium score regression analyses revealed that gestational diabetes mellitus had a significant genetic correlation with coronary artery disease and myocardial infarction after Benjamini-Hochberg correction in ever-pregnant women. In Mendelian randomization analyses, odds ratios (95% confidence interval) for coronary artery disease and myocardial infarction were 1.09 (1.01-1.17) and 1.12 (.96-1.31) per unit increase in the log-odds of genetic predisposition to gestational diabetes mellitus in ever-pregnant women, respectively. Further, Type 2 diabetes and hypertension were identified as mediators for the causality of genetic predisposition to gestational diabetes mellitus on coronary artery disease. In sensitivity analyses, the direction of odds ratio for the association between instrumental variables with gestational diabetes mellitus-predominant effects and the risk of coronary artery disease was consistent with the primary results in ever-pregnant women, although not statistically significant. CONCLUSIONS: This study demonstrated a suggestive causal relationship between genetic predisposition to gestational diabetes mellitus and the risk of coronary artery disease, which was mainly mediated by Type 2 diabetes and hypertension. These findings highlight targeting modifiable cardiometabolic risk factors may reduce the risk of coronary artery disease in women with a history of gestational diabetes mellitus.

The inflammatory and oxidative phenotype of gestational diabetes is epigenetically transmitted to the offspring: role of methyltransferase MLL1-induced H3K4me3.

BACKGROUND AND AIMS: Hyperglycaemia during gestational diabetes (GD) predisposes women and their offspring to later cardiometabolic disease. The hyperglycaemia-mediated epigenetic changes remain to be elucidated. Methyltransferase MLL1-induced trimethylation of histone 3 at lysine 4 (H3K4me3) activates inflammatory and oxidative phenotype. This epigenetic mark in GD women and its transmission to the offspring were investigated. METHODS: Peripheral blood mononuclear cells (PBMC) were collected from GD and control (C) women and also from adolescents born to women of both groups. Endothelial human umbilical vein endothelial cells (HUVEC) and cord blood mononuclear cells (CBMC) were from umbilical cords. The NF-κBp65 and NOX4 expressions were investigated by reverse transcription quantitative polymerase chain reaction and immunofluorescence (IF). MLL1 and H3K4me3 were investigated by immunoblotting and IF. H3K4me3 on NF-κBp65 and NOX4 promoters was studied by chromatin immunoprecipitation. Superoxide anion generation was measured by electron spin resonance spectroscopy. Plasma cytokines were measured by enzyme-linked immunosorbent assay. To investigate the role of MLL1, HUVEC were exposed to inhibitor MM102 or siRNA transfection. RESULTS: PBMC, CBMC, and HUVEC showed an increase of NF-κBp65, IL-6, ICAM-1, MCP-1, and VCAM-1 mRNAs. These findings were associated with H3K4me3 enrichment in the promoter of NF-κBp65. Elevated H3K4me3 and cytokine levels were observed in GD adolescents. MLL1 drives H3K4me3 not only on NF-kB p65, but also on NOX4 promoter. Inhibition of MLL1 blunted NF-κBp65 and NOX4 by modulating inflammatory and oxidative phenotype. CONCLUSIONS: Such proof-of-concept study shows persistence of MLL1-dependent H3K4me3 in offspring born to GD women, suggesting an epigenetic-driven transmission of maternal phenotype. These findings may pave the way for pharmacological reprogramming of adverse histone modifications to mitigate abnormal phenotypes underlying early ASCVD.

Glucose and oxygen in the early intrauterine environment and their role in developmental abnormalities.

The early life environment can have profound impacts on the developing conceptus in terms of both growth and morphogenesis. These impacts can manifest in a variety of ways, including congenital fetal anomalies, placental dysfunction with subsequent effects on fetal growth, and adverse perinatal outcomes, or via effects on long-term health outcomes that may not be detected until later childhood or adulthood. Two key examples of environmental influences on early development are explored: maternal hyperglycaemia and gestational hypoxia. These are increasingly common pregnancy exposures worldwide, with potentially profound impacts on population health. We explore what is known regarding the mechanisms by which these environmental exposures can impact early intrauterine development and thus result in adverse outcomes in the immediate, short, and long term.

Implications of pregnancy on cardiometabolic disease risk: preeclampsia and gestational diabetes.

Cardiometabolic disorders, such as obesity, insulin resistance, and hypertension, prior to and within pregnancy are increasing in prevalence worldwide. Pregnancy-associated cardiometabolic disease poses a great risk to the short- and long-term well-being of the mother and offspring. Hypertensive pregnancy, notably preeclampsia, as well as gestational diabetes are the major diseases of pregnancy growing in prevalence as a result of growing cardiometabolic disease prevalence. The mechanisms whereby obesity, diabetes, and other comorbidities lead to preeclampsia and gestational diabetes are incompletely understood and continually evolving in the literature. In addition, novel therapeutic avenues are currently being explored in these patients to offset cardiometabolic-induced adverse pregnancy outcomes in preeclamptic and gestational diabetes pregnancies. In this review, we discuss the emerging pathophysiological mechanisms of preeclampsia and gestational diabetes in the context of cardiometabolic risk as well as the most recent preclinical and clinical updates in the pathogenesis and treatment of these conditions.

Sex-Specific Alterations in Placental Proteomics Induced by Intrauterine Hyperglycemia.

Gestational diabetes mellitus (GDM) with intrauterine hyperglycemia induces a series of changes in the placenta, which have adverse effects on both the mother and the fetus. The aim of this study was to investigate the changes in the placenta in GDM and its gender differences. In this study, we established an intrauterine hyperglycemia model using ICR mice. We collected placental specimens from mice before birth for histological observation, along with tandem mass tag (TMT)-labeled proteomic analysis, which was stratified by sex. When the analysis was not segregated by sex, the GDM group showed 208 upregulated and 225 downregulated proteins in the placenta, primarily within the extracellular matrix and mitochondria. Altered biological processes included cholesterol metabolism and oxidative stress responses. After stratification by sex, the male subgroup showed a heightened tendency for immune-related pathway alterations, whereas the female subgroup manifested changes in branched-chain amino acid metabolism. Our study suggests that the observed sex differences in placental protein expression may explain the differential impact of GDM on offspring.

ChIP-seq and RNA-seq Reveal the Involvement of Histone Lactylation Modification in Gestational Diabetes Mellitus.

Lactylation is a novel post-translational modification of proteins. Although the histone lactylation modification has been reported to be involved in glucose metabolism, its role and molecular pathways in gestational diabetes mellitus (GDM) are still unclear. This study aims to elucidate the histone lactylation modification landscapes of GDM patients and explore lactylation-modification-related genes involved in GDM. We employed a combination of RNA-seq analysis and chromatin immunoprecipitation sequencing (ChIP-seq) analysis to identify upregulated differentially expressed genes (DEGs) with hyperhistone lactylation modification in GDM. We demonstrated that the levels of lactate and histone lactylation were significantly elevated in GDM patients. DEGs were involved in diabetes-related pathways, such as the PI3K-Akt signaling pathway, Jak-STAT signaling pathway, and mTOR signaling pathway. ChIP-seq analysis indicated that histone lactylation modification in the promoter regions of the GDM group was significantly changed. By integrating the results of RNA-seq and ChIP-seq analysis, we found that CACNA2D1 is a key gene for histone lactylation modification and is involved in the progression of GDM by promoting cell vitality and proliferation. In conclusion, we identified the key gene CACNA2D1, which upregulated and exhibited hypermodification of histone lactylation in GDM. These findings establish a theoretical groundwork for the targeted therapy of GDM.

Metformin and small for gestational age babies: findings of a randomised placebo-controlled clinical trial of metformin in gestational diabetes (EMERGE).

AIMS/HYPOTHESIS: Gestational diabetes mellitus (GDM) is associated with adverse perinatal outcomes because of suboptimal glucose management and glucose control and excessive weight gain. Metformin can offset these factors but is associated with small for gestational age (SGA) infants. We sought to identify risk factors for SGA infants, including the effect of metformin exposure on SGA status. METHODS: In this prespecified secondary analysis of the EMERGE trial, which evaluated the effectiveness of metformin vs placebo in treating GDM and found reduced gestational weight gain and longer time to insulin initiation with metformin use, we included women with a live-born infant and known infant birthweight and gestational age at delivery. We compared the numbers of SGA infants in both groups and explored baseline predictive factors to help identify those at highest risk of delivering an SGA infant. RESULTS: Baseline maternal characteristics were similar between SGA and non-SGA pregnancies. On multivariable-adjusted regression, no baseline maternal variables were associated with SGA status. Mothers of SGA infants were more likely to develop pre-eclampsia or gestational hypertension (18.2% vs 2.0%, p=0.001; 22.7% vs 5.4%, p=0.005, respectively); after multivariable adjustment, pre-eclampsia was positively associated with SGA status). Among SGA pregnancies, important perinatal outcomes including preterm birth, Caesarean delivery and neonatal care unit admission did not differ between the metformin and placebo groups (20.0% vs 14.3%, p=1.00; 50.0% vs 28.6%, p=0.25; 13.3% vs 42.9%, p=0.27, respectively). CONCLUSIONS/INTERPRETATION: Pre-eclampsia was strongly associated with SGA infants. Metformin-exposed SGA infants did not display a more severe SGA phenotype than infants treated with placebo. TRIAL REGISTRATION: Clinical Trials.gov NCT02980276; EudraCT number: 2016-001644-19.

Habitual carbohydrate intake is not correlated with circulating ß-hydroxybutyrate levels in pregnant women with overweight and obesity at 28 weeks' gestation.

AIMS/HYPOTHESIS: Pregnant women are advised to consume a minimum of 175 g per day of carbohydrate to meet maternal and fetal brain glucose requirements. This recommendation comes from a theoretical calculation of carbohydrate requirements in pregnancy, rather than from clinical data. This study aimed to determine whether fasting maternal ketone levels are associated with habitual carbohydrate intake in a subset of participants of the Study of PRobiotics IN Gestational diabetes (SPRING) randomised controlled trial. METHODS: Food frequency questionnaires on dietary intake during pregnancy were completed by pregnant women with overweight or obesity at 28 weeks' gestation (considering their intake from the beginning of pregnancy). Dietary intake from early pregnancy through to 28 weeks was analysed for macronutrient intake. At the same time, overnight fasting serum samples were obtained and analysed for metabolic parameters including serum ß-hydroxybutyrate, OGTTs, insulin and C-peptide. RESULTS: Fasting serum ß-hydroxybutyrate levels amongst 108 women (mean BMI 34.7 ± 6.3 kg/m2) ranged from 22.2 to 296.5 µmol/l. Median fasting ß-hydroxybutyrate levels were not different between women with high (median [IQR] 68.4 [49.1-109.2 µmol/l]) and low (65.4 [43.6-138.0 µmol/l]) carbohydrate intake in pregnancy. Fasting ß-hydroxybutyrate levels were not correlated with habitual carbohydrate intake (median 155 [126-189] g/day). The only metabolic parameter with which fasting ß-hydroxybutyrate levels were correlated was 1 h venous plasma glucose (ρ=0.23, p=0.03) during a 75 g OGTT. CONCLUSIONS/INTERPRETATION: Fasting serum ß-hydroxybutyrate levels are not associated with habitual carbohydrate intake at 28 weeks' gestation in pregnant women with overweight and obesity.

Metabolomic and genetic architecture of gestational diabetes subtypes.

AIMS/HYPOTHESIS: Physiological gestational diabetes mellitus (GDM) subtypes that may confer different risks for adverse pregnancy outcomes have been defined. The aim of this study was to characterise the metabolome and genetic architecture of GDM subtypes to address the hypothesis that they differ between GDM subtypes. METHODS: This was a cross-sectional study of participants in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study who underwent an OGTT at approximately 28 weeks' gestation. GDM was defined retrospectively using International Association of Diabetes and Pregnancy Study Groups/WHO criteria, and classified as insulin-deficient GDM (insulin secretion <25th percentile with preserved insulin sensitivity) or insulin-resistant GDM (insulin sensitivity <25th percentile with preserved insulin secretion). Metabolomic analyses were performed on fasting and 1 h serum samples in 3463 individuals (576 with GDM). Genome-wide genotype data were obtained for 8067 individuals (1323 with GDM). RESULTS: Regression analyses demonstrated striking differences between the metabolomes for insulin-deficient or insulin-resistant GDM compared to those with normal glucose tolerance. After adjustment for covariates, 33 fasting metabolites, including 22 medium- and long-chain acylcarnitines, were uniquely associated with insulin-deficient GDM; 23 metabolites, including the branched-chain amino acids and their metabolites, were uniquely associated with insulin-resistant GDM; two metabolites (glycerol and 2-hydroxybutyrate) were associated with the same direction of association with both subtypes. Subtype differences were also observed 1 h after a glucose load. In genome-wide association studies, variants within MTNR1B (rs10830963, p=3.43×10-18, OR 1.55) and GCKR (rs1260326, p=5.17×10-13, OR 1.43) were associated with GDM. Variants in GCKR (rs1260326, p=1.36×10-13, OR 1.60) and MTNR1B (rs10830963, p=1.22×10-9, OR 1.49) demonstrated genome-wide significant association with insulin-resistant GDM; there were no significant associations with insulin-deficient GDM. The lead SNP in GCKR, rs1260326, was associated with the levels of eight of the 25 fasting metabolites that were associated with insulin-resistant GDM and ten of 41 1 h metabolites that were associated with insulin-resistant GDM. CONCLUSIONS/INTERPRETATION: This study demonstrates that physiological GDM subtypes differ in their metabolome and genetic architecture. These findings require replication in additional cohorts, but suggest that these differences may contribute to subtype-related adverse pregnancy outcomes.

Lifetime history of gestational diabetes and cognitive function in parous women in midlife.

AIMS/HYPOTHESIS: We aimed to determine whether a history of gestational diabetes mellitus (GDM) is associated with cognitive function in midlife. METHODS: We conducted a secondary data analysis of the prospective Nurses' Health Study II. From 1989 to 2001, and then in 2009, participants reported their history of GDM. A subset participated in a cognition sub-study in 2014-2019 (wave 1) or 2018-2022 (wave 2). We included 15,906 parous participants (≥1 birth at ≥18 years) who completed a cognitive assessment and were free of CVD, cancer and diabetes before their first birth. The primary exposure was a history of GDM. Additionally, we studied exposure to GDM and subsequent type 2 diabetes mellitus (neither GDM nor type 2 diabetes, GDM only, type 2 diabetes only or GDM followed by type 2 diabetes) and conducted mediation analysis by type 2 diabetes. The outcomes were composite z scores measuring psychomotor speed/attention, learning/working memory and global cognition obtained with the Cogstate brief battery. Mean differences (ß and 95% CI) in cognitive function by GDM were estimated using linear regression. RESULTS: The 15,906 participants were a mean of 62.0 years (SD 4.9) at cognitive assessment, and 4.7% (n=749) had a history of GDM. In models adjusted for age at cognitive assessment, race and ethnicity, education, wave of enrolment in the cognition sub-study, socioeconomic status and pre-pregnancy characteristics, women with a history of GDM had lower performance in psychomotor speed/attention (ß -0.08; 95% CI -0.14, -0.01) and global cognition (ß -0.06; 95% CI -0.11, -0.01) than those without a history of GDM. The lower cognitive performance in women with GDM was only partially explained by the development of type 2 diabetes. CONCLUSIONS/INTERPRETATION: Women with a history of GDM had poorer cognition than those without GDM. If replicated, our findings support future research on early risk modification strategies for women with a history of GDM as a potential avenue to decrease their risk of cognitive impairment.