The effect of different forms of dysglycemia during pregnancy on maternal and fetal outcomes in treated women and comparison with large cohort studies

Causal relationship between citrate and gestational diabetes mellitus: a two-sample Mendelian randomization analysis

BACKGROUND

Diabetes Mellitus (GDM) is a common metabolic disease during pregnancy, mainly manifested as impaired glucose tolerance in the middle and late stages of pregnancy. As a key intermediate product in the tricarboxylic acid cycle, citrate has been widely recognized for its role in regulating blood glucose levels. However, the potential association between citrate and impaired glucose tolerance during pregnancy needs further research, The aim of this study is to investigate the relationship between citrate levels in the human body and the incidence of gestational diabetes mellitus.

METHOD

This study adopts a two-sample Mendelian randomization approach, using genetic variants of citrate as instrumental variables, to investigate the causal relationship between citrate and gestational diabetes mellitus (GDM). The research data is derived from the OpenGWAS and FinnGen databases, with single nucleotide polymorphisms (SNPs) related to citrate levels and the incidence of GDM selected as analytical tools. Citrate is designated as the exposure factor, and GDM as the outcome variable. Comprehensive assessments of the causal relationship between the instrumental variables and GDM are conducted using methods such as Inverse Variance Weighted (IVW), MR Egger, Simple Mode, Weighted Median, and Weighted Mode. Additionally, Cochran's Q and I^2 statistics are utilized to evaluate heterogeneity, with visualization provided through funnel plots. To test the robustness of the results, a leave-one-out sensitivity analysis method is employed. Furthermore, the potential pleiotropy in this study is detected using MR Egger.

RESULT

In this study, a total of 6 SNPs related to citrate were included. The MR causal analysis revealed that the relevant genes of citrate had a significant impact on gestational diabetes mellitus in both the Inverse Variance Weighted method (OR = 0.170, 95% CI: 0.032 to 0.896, p = 0.037) and the Weighted Median method (OR = 0.116, 95% CI: 0.016 to 0.844, p = 0.033). The tests for heterogeneity, pleiotropy, and sensitivity used in this experiment all indicated that there were no special interfering factors in this experiment.

CONCLUSION

This study found that there is a negative correlation between the level of citrate in pregnant women and gestational diabetes mellitus.

Pregestational Diabetes and Adverse Pregnancy Results: A Mendelian Randomization Study

BACKGROUND

Hyperglycemia in pregnancy is believed to be associated with negative pregnancy outcomes. However, establishing a causal connection between diabetes mellitus (DM) and adverse pregnancy results is challenging due to the limitations inherent in traditional observational studies.

METHODS

Our study used a two-sample Mendelian randomization (MR) technique to examine the possible influence of pregestational diabetes mellitus (PGDM) on adverse pregnancy outcomes. Summary-level data were obtained from genome-wide association studies (GWAS) of European ancestry and FinnGen biobank. The primary analysis employed the random-effects multiplicative inverse variance weighted (IVW) technique to appraise causal relationships between PGDM and adverse outcomes. Heterogeneity and pleiotropy were assessed using Cochran's Q statistic, Rucker's Q statistic, and the I² statistic. Sensitivity analyses were conducted using MR-Egger and weighted median methods. Additionally, outlier detection techniques, including MR-PRESSO and RadialMR, were applied.

RESULTS

The results from the IVW method indicated no significant causal association between PGDM and stillbirth (SB) (OR (SE)=0.99 (0.001); P value=0.992), miscarriage (MIS) (OR (SE)=0.97 (0.016); P value=0.125), and preterm birth (PTB) (OR (SE)=1.072 (0.028); P value=0.014). Pleiotropy and heterogeneity tests revealed no evidence of pleiotropy for SB, MIS, and PTB (MR-Egger intercept P value=0.296, 0.525, and 0.532, respectively), with no observed heterogeneity for SB, MIS, and PTB (Q- P values of IVW were 0.929, 0.999, and 0.069, and MR-Egger were 0.931, 0.999, and 0.065, respectively).

CONCLUSION

Our findings indicate that there is no direct causal link between PGDM and the likelihood of MIS, SB, and PTB.

Differential effects of delayed cord clamping on bilirubin levels in normal and diabetic pregnancies

The purpose of the study is to investigate the effects of delayed cord clamping on bilirubin levels and phototherapy rates in neonates of diabetic mothers. This was a prospective study that enrolled pregnant women without pregnancy complications and those with diabetes. Their neonates were randomized in a 1:1 ratio to delayed cord clamping. The main outcomes were the neonatal transcutaneous bilirubin values on 2-4 days postpartum and the rate of requiring phototherapy in infants. A total of 261 pregnant women were included in the final analysis (132 women with diabetic pregnancies and 129 women with normal pregnancies). In diabetic pregnancies, neonatal bilirubin levels on the 2-4 days postpartum and phototherapy rates were significantly higher in the delayed cord clamping group than in the immediate cord clamping group (7.65 ± 1.83 vs 8.25 ± 1.96, P = 0.039; 10.35 ± 2.23 vs 11.54 ± 2.56, P = 0.002; 11.54 ± 2.94 vs 12.83 ± 3.07 P = 0.024, 18.2% vs 6.3%, P = 0.042), while in normal pregnancies, there was no statistical difference in bilirubin values and phototherapy rates between the delayed cord clamping group and the immediate cord clamping group (P > 0.05). After receiving delayed cord clamping, bilirubin levels on the third postnatal day and the rate of requiring phototherapy in infants were higher in the diabetic pregnancy group than in the normal pregnancy group (10.35 ± 2.23 vs 11.54 ± 2.56, P = 0.013).

CONCLUSION

Delayed cord clamping increased the risk of jaundice in newborns born to diabetic mothers, but had no effect in newborns from mothers with normal pregnancies. DCC may be a risk factor for increased bilirubin in infants of diabetic mothers.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT04369313; date of registration: April 27, 2020 (retrospectively registered).

WHAT IS KNOWN

• Delayed cord clamping had significant benefits for newborns by increasing neonatal hemoglobin levels and reducing the risk of neonatal anemia, etc. • Delayed cord clamping may lead to neonatal hyperemia, erythrocytosis, and hyperbilirubinemia, which increases the risk of neonatal jaundice.

WHAT IS NEW

• Our trial focused on the differential effects of delayed cord clamping on jaundice in full-term newborns between diabetic pregnancies and normal pregnancies. And newborns of diabetic mothers who received delayed cord clamping had a significantly increased risk of jaundice compared to newborns with normal pregnancy. • Delayed cord clamping may be a risk factor for increased bilirubin levels in neonates of diabetic mothers.

Gestational diabetes mellitus and adverse pregnancy outcomes: systematic review and meta-analysis

OBJECTIVE

To investigate the association between gestational diabetes mellitus and adverse outcomes of pregnancy after adjustment for at least minimal confounding factors.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

Web of Science, PubMed, Medline, and Cochrane Database of Systematic Reviews, from 1 January 1990 to 1 November 2021.

REVIEW METHODS

Cohort studies and control arms of trials reporting complications of pregnancy in women with gestational diabetes mellitus were eligible for inclusion. Based on the use of insulin, studies were divided into three subgroups: no insulin use (patients never used insulin during the course of the disease), insulin use (different proportions of patients were treated with insulin), and insulin use not reported. Subgroup analyses were performed based on the status of the country (developed or developing), quality of the study, diagnostic criteria, and screening method. Meta-regression models were applied based on the proportion of patients who had received insulin.

RESULTS

156 studies with 7 506 061 pregnancies were included, and 50 (32.1%) showed a low or medium risk of bias. In studies with no insulin use, when adjusted for confounders, women with gestational diabetes mellitus had increased odds of caesarean section (odds ratio 1.16, 95% confidence interval 1.03 to 1.32), preterm delivery (1.51, 1.26 to 1.80), low one minute Apgar score (1.43, 1.01 to 2.03), macrosomia (1.70, 1.23 to 2.36), and infant born large for gestational age (1.57, 1.25 to 1.97). In studies with insulin use, when adjusted for confounders, the odds of having an infant large for gestational age (odds ratio 1.61, 1.09 to 2.37), or with respiratory distress syndrome (1.57, 1.19 to 2.08) or neonatal jaundice (1.28, 1.02 to 1.62), or requiring admission to the neonatal intensive care unit (2.29, 1.59 to 3.31), were higher in women with gestational diabetes mellitus than in those without diabetes. No clear evidence was found for differences in the odds of instrumental delivery, shoulder dystocia, postpartum haemorrhage, stillbirth, neonatal death, low five minute Apgar score, low birth weight, and small for gestational age between women with and without gestational diabetes mellitus after adjusting for confounders. Country status, adjustment for body mass index, and screening methods significantly contributed to heterogeneity between studies for several adverse outcomes of pregnancy.

CONCLUSIONS

When adjusted for confounders, gestational diabetes mellitus was significantly associated with pregnancy complications. The findings contribute to a more comprehensive understanding of the adverse outcomes of pregnancy related to gestational diabetes mellitus. Future primary studies should routinely consider adjusting for a more complete set of prognostic factors.

REVIEW REGISTRATION

PROSPERO CRD42021265837.

Characteristics of the gut microbiome in women with gestational diabetes mellitus: A systematic review

Background

The incidence of women developing gestational diabetes mellitus (GDM) is increasing, which is associated with an increased risk of type 2 diabetes mellitus (T2DM) for both mother and child. Gut microbiota dysbiosis may contribute to the pathogenesis of both GDM and the accompanying risk of T2DM. Thus, a better understanding of the microbial communities associated with GDM could offer a potential target for intervention and treatment in the future. Therefore, we performed a systematic review to investigate if the GDM women have a distinct gut microbiota composition compared to non-GDM women.

Methods

We identified 21 studies in a systematic literature search of Embase and PubMed up to February 24, 2021. Data on demographics, methodology and identified microbial metrics were extracted. The quality of each study was assessed according to the Newcastle-Ottawa Scale.

Results

Sixteen of the studies did find a GDM-associated gut microbiota, although no consistency could be seen. Only Collinsella and Blautia showed a tendency to be increased in GDM women, whereas the remaining genera were significantly different in opposing directions.

Conclusion

Although most of the studies found an association between GDM and gut microbiota dysbiosis, no overall GDM-specific gut microbiota could be identified. All studies in the second trimester found a difference between GDM and non-GDM women, indicating that dysbiosis is present at the time of diagnosis. Nevertheless, it is still unclear when the dysbiosis develops, as no consensus could be seen between the studies investigating the gut microbiota in the first trimester of pregnancy. However, studies varied widely concerning methodology and study design, which might explain the highly heterogeneous gut microbiota compositions between studies. Therefore, future studies need to include multiple time points and consider possible confounding factors such as ethnicity, pre-pregnancy body mass index, and GDM treatment.

Risks of specific congenital anomalies in offspring of women with diabetes: A systematic review and meta-analysis of population-based studies including over 80 million births

BACKGROUND

Pre-gestational diabetes mellitus (PGDM) has been known to be a risk factor for congenital heart defects (CHDs) for decades. However, the associations between maternal PGDM and gestational diabetes mellitus (GDM) and the risk of specific types of CHDs and congenital anomalies (CAs) in other systems remain under debate. We aimed to investigate type-specific CAs in offspring of women with diabetes and to examine the extent to which types of maternal diabetes are associated with increased risk of CAs in offspring.

METHODS AND FINDINGS

We searched PubMed and Embase from database inception to 15 October 2021 for population-based studies reporting on type-specific CAs in offspring born to women with PGDM (combined type 1 and 2) or GDM, with no limitation on language. Reviewers extracted data for relevant outcomes and performed random effects meta-analyses, subgroup analyses, and multivariable meta-regression. Risk of bias appraisal was performed using the Cochrane Risk of Bias Tool. This study was registered in PROSPERO (CRD42021229217). Primary outcomes were overall CAs and CHDs. Secondary outcomes were type-specific CAs. Overall, 59 population-based studies published from 1990 to 2021 with 80,437,056 participants met the inclusion criteria. Of the participants, 2,407,862 (3.0%) women had PGDM and 2,353,205 (2.9%) women had GDM. The meta-analyses showed increased risks of overall CAs/CHDs in offspring born to women with PGDM (for overall CAs, relative risk [RR] = 1.99, 95% CI 1.82 to 2.17, P < 0.001; for CHDs, RR = 3.46, 95% CI 2.77 to 4.32, P < 0.001) or GDM (for overall CAs, RR = 1.18, 95% CI 1.13 to 1.23, P < 0.001; for CHDs, RR = 1.50, 95% CI 1.38 to 1.64, P < 0.001). The results of the meta-regression analyses showed significant differences in RRs of CAs/CHDs in PGDM versus GDM (all P < 0.001). Of the 23 CA categories, excluding CHD-related categories, in offspring, maternal PGDM was associated with a significantly increased risk of CAs in 21 categories; the corresponding RRs ranged from 1.57 (for hypospadias, 95% CI 1.22 to 2.02) to 18.18 (for holoprosencephaly, 95% CI 4.03 to 82.06). Maternal GDM was associated with a small but significant increase in the risk of CAs in 9 categories; the corresponding RRs ranged from 1.14 (for limb reduction, 95% CI 1.06 to 1.23) to 5.70 (for heterotaxia, 95% CI 1.09 to 29.92). The main limitation of our analysis is that some high significant heterogeneity still persisted in both subgroup and sensitivity analyses.

CONCLUSIONS

In this study, we observed an increased rate of CAs in offspring of women with diabetes and noted the differences for PGDM versus GDM. The RRs of overall CAs and CHDs in offspring of women with PGDM were higher than those in offspring of women with GDM. Screening for diabetes in pregnant women may enable better glycemic control, and may enable identification of offspring at risk for CAs.

The association between gestational diabetes and stillbirth: a systematic review and meta-analysis

AIMS/HYPOTHESIS

Controversy exists over whether gestational diabetes increases the risk of stillbirth. The aim of this review was to examine the association between gestational diabetes and stillbirth.

METHODS

We performed searches of the published literature to May 2021. Study selection and data extraction were performed in duplicate by independent reviewers. Meta-analyses of summary measures were conducted using random-effect models for cohort and case-control studies separately. The study protocol was registered in PROSPERO (registration ID CRD42020166939).

RESULTS

From 9981 citations, 419 were identified for full-text review and 73 met inclusion criteria (n = 70,292,090). There was no significant association between gestational diabetes and stillbirth in cohort studies (pooled OR 1.04 [95% CI 0.90, 1.21]; I2 86.1%) or in case-control studies (pooled OR 1.57 [95% CI 0.83, 2.98]; I2 94.8%). Gestational diabetes was associated with lower odds of stillbirth among cohort studies presenting with an adjusted OR (pooled OR 0.78 [95% CI 0.68, 0.88]; I2 42.7%). Stratified analyses by stillbirth ≥28 weeks' gestation, studies published prior to 2013 and studies identified as low quality demonstrated a significantly higher odds of stillbirth in meta-regression (p = 0.016, 0.023 and 0.005, respectively). Egger's test for all included cohort studies (p = 0.018) suggests publication bias for the main meta-analysis.

CONCLUSIONS/INTERPRETATION

Given the substantial heterogeneity across studies, there are insufficient data to define the relationship between stillbirth and gestational diabetes adequately. In the main analyes, gestational diabetes was not associated with an increased risk of stillbirth. However, heterogeneity across studies means this finding should be interpreted cautiously.

Diabetes during Pregnancy: A Maternal Disease Complicating the Course of Pregnancy with Long-Term Deleterious Effects on the Offspring. A Clinical Review

In spite of the huge progress in the treatment of diabetes mellitus, we are still in the situation that both pregestational (PGDM) and gestational diabetes (GDM) impose an additional risk to the embryo, fetus, and course of pregnancy. PGDM may increase the rate of congenital malformations, especially cardiac, nervous system, musculoskeletal system, and limbs. PGDM may interfere with fetal growth, often causing macrosomia, but in the presence of severe maternal complications, especially nephropathy, it may inhibit fetal growth. PGDM may also induce a variety of perinatal complications such as stillbirth and perinatal death, cardiomyopathy, respiratory morbidity, and perinatal asphyxia. GDM that generally develops in the second half of pregnancy induces similar but generally less severe complications. Their severity is higher with earlier onset of GDM and inversely correlated with the degree of glycemic control. Early initiation of GDM might even cause some increase in the rate of congenital malformations. Both PGDM and GDM may cause various motor and behavioral neurodevelopmental problems, including an increased incidence of attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). Most complications are reduced in incidence and severity with the improvement in diabetic control. Mechanisms of diabetic-induced damage in pregnancy are related to maternal and fetal hyperglycemia, enhanced oxidative stress, epigenetic changes, and other, less defined, pathogenic mechanisms.

Could Subtle Obstetrical Brachial Plexus Palsy Be Related to Unilateral B Glenoid Osteoarthritis?

Background: Several factors associated with B glenoid are also linked with obstetrical brachial plexus palsy (OBPP). The purpose of this observational study was to determine the incidence of OBPP risk factors in type B patients. Methods: A cohort of 154 patients (68% men, 187 shoulders) aged 63 ± 17 years with type B glenoids completed a questionnaire comprising history of perinatal characteristics related to OBPP. A literature review was performed following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) to estimate the incidence of OBPP risk factors in the general population. Results: Twenty-seven patients (18%) reported one or more perinatal OBPP risk factors, including shoulder dystocia (n = 4, 2.6%), macrosomia >4 kg (n = 5, 3.2%), breech delivery (n = 6, 3.9%), fetal distress (n = 8, 5.2%), maternal diabetes (n = 2, 1.3%), clavicular fracture (n = 2, 1.3%), and forceps delivery (n = 4, 2.6%). The comparison with the recent literature suggested that most perinatal OBPP risk factors were within the normal range, although the incidence of shoulder dystocia, forceps and vaginal breech deliveries exceeded the average rates. Conclusion: Perinatal factors related to OBPP did not occur in a higher frequency in patients with Walch type B OA compared to the general population, although some of them were in the high normal range.

The Impact of Diagnostic Criteria for Gestational Diabetes Mellitus on Adverse Maternal Outcomes: A Systematic Review and Meta-Analysis

This systematic review and meta-analysis aimed to examine the impact of different gestational-diabetes (GDM) diagnostic-criteria on the risk of adverse-maternal-outcomes. The search process encompassed PubMed (Medline), Scopus, and Web of Science databases to retrieve original, population-based studies with the universal GDM screening approach, published in English language and with a focus on adverse-maternal-outcomes up to January 2020. According to GDM diagnostic criteria, the studies were classified into seven groups. A total of 49 population-based studies consisting of 1409018 pregnant women with GDM and 7,667,546 non-GDM counterparts were selected for data analysis and knowledge synthesis. Accordingly, the risk of adverse-maternal-outcomes including primary-cesarean, induction of labor, maternal-hemorrhage, and pregnancy-related-hypertension, overall, regardless of GDM diagnostic-criteria and in all diagnostic-criteria subgroups were significantly higher than non-GDM counterparts. However, in meta-regression, the increased risk was not influenced by the GDM diagnostic-classification and the magnitude of the risks among patients, using the IADPSG criteria-classification as the most strict-criteria, was similar to other criteria. In conclusion, a reduction in the diagnostic-threshold increased the prevalence of GDM, but the risk of adverse-maternal-outcome was not different among those women who were diagnosed through more or less intensive strategies. Our review findings can empower health-care-providers to select the most cost-effective approach for the screening of GDM among pregnant women.

Prevalence of Gestational Diabetes Mellitus in the Middle East and North Africa, 2000-2019: A Systematic Review, Meta-Analysis, and Meta-Regression

Women in the Middle East and North Africa (MENA) region are burdened with several risk factors related to gestational diabetes mellitus (GDM) including overweight and high parity. We systematically reviewed the literature and quantified the weighted prevalence of GDM in MENA at the regional, subregional, and national levels. Studies published from 2000 to 2019 reporting the prevalence of GDM in the MENA region were retrieved and were assessed for their eligibility. Overall and subgroup pooled prevalence of GDM was quantified by random-effects meta-analysis. Sources of heterogeneity were investigated by meta-regression. The risk of bias (RoB) was assessed by the National Heart, Lung, and Blood Institute's tool. One hundred and two research articles with 279,202 tested pregnant women for GDM from 16 MENA countries were included. Most of the research reports sourced from Iran (36.3%) and Saudi Arabia (21.6%), with an overall low RoB. In the 16 countries, the pooled prevalence of GDM was 13.0% (95% confidence interval [CI], 11.5-14.6%, I² , 99.3%). Nationally, GDM was highest in Qatar (20.7%, 95% CI, 15.2-26.7% I² , 99.0%), whereas subregionally, GDM was highest in Gulf Cooperation Council (GCC) countries (14.7%, 95% CI, 13.0-16.5%, I² , 99.0%). The prevalence of GDM was high in pregnant women aged ≥30 years (21.9%, 95% CI, 18.5-25.5%, I² , 97.1%), in their third trimester (20.0%, 95% CI, 13.1-27.9%, I² , 98.8%), and who were obese (17.2%, 95% CI, 12.8-22.0%, I² , 93.8%). The prevalence of GDM was 10.6% (95% CI, 8.1-13.4%, I² , 98.9%) in studies conducted before 2009, whereas it was 14.0% (95% CI, 12.1-16.0%, I² , 99.3%) in studies conducted in or after 2010. Pregnant women in the MENA region are burdened with a substantial prevalence of GDM, particularly in GCC and North African countries. Findings have implications for maternal health in the MENA region and call for advocacy to unify GDM diagnostic criteria.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018100629.

Comparative risks and predictors of preeclamptic pregnancy in the Eastern, Western and developing world

Preeclampsia (PE) is a complication of pregnancy characterized by hypertension (HTN-Preg), and often proteinuria. If not managed promptly, PE could lead to eclampsia and seizures. PE could also lead to intrauterine growth restriction (IUGR) and prematurity at birth. Although PE is a major cause of maternal and fetal morbidity and mortality, the underlying mechanisms are unclear. Also, there is a wide variability in the incidence of PE, ranging between 2 and 8% of pregnancies in the Eastern, Western and Developing world, suggesting regional differences in the risk factors and predictors of the pregnancy-related disorder. Several demographic, genetic, dietary and environmental factors, as well as maternal circulating biomarkers have been associated with PE. Demographic factors such as maternal race and ethnicity could play a role in PE. Specific genetic polymorphisms have been identified in PE. Maternal age, parity, education and socioeconomic status could be involved in PE. Dietary fat, protein, calcium and vitamins, body weight, and environmental factors including climate changes and air pollutants could also play a role in PE. Several circulating cytoactive factors including anti-angiogenic factors and cytokines have also been associated with PE. Traditional midwifery care is a common practice in local maternity care units, while advanced perinatal care and new diagnostic tools such as uterine artery Doppler velocimetry have been useful in predicting early PE in major medical centers. These PE risk factors, early predictors and diagnostic tools vary vastly in different regions of the Eastern, Western and Developing world. Further understanding of the differences in the demographic, genetic, dietary and environmental factors among pregnant women in different world regions should help in designing a region-specific cluster of risk factors and predictors of PE, and in turn provide better guidance for region-specific tools for early detection and management of PE.