Incidence of gestational diabetes and birth complications in Switzerland: screening in 1042 pregnancies

Evolution of Gestational Diabetes Mellitus across Continents in 21st Century

Over the last few decades, several definitions of gestational diabetes mellitus (GDM) have been described. There is currently not enough research to show which way is the best to diagnose GDM. Opinions differ in terms of the optimal screening and diagnostic measures, in part due to the differences in the population risks, the cost-effectiveness considerations, and the lack of an evidence base to support large national screening programs. The basic method for identifying the disease is the measurement of glucose plasma levels which may be determined when fasting, two hours after a meal, or simply at any random time. The currently increasing incidence of diabetes in the whole population, the altering demographics and the presence of lifestyle changes still require better methods of screening for hyperglycemia, especially during pregnancy. The main aim of this review is to focus on the prevalence and modifications to the screening criteria for GDM across all continents in the 21st century. We would like to show the differences in the above issues and correlate them with the geographical situation. Looking at the history of diabetes, we are sure that more than one evolution in GDM diagnosis will occur, due to the development of medicine, appearance of modern technologies, and the dynamic continuation of research.

Recording of Chronic Diseases and Adverse Obstetric Outcomes during Hospitalizations for a Delivery in the National Swiss Hospital Medical Statistics Dataset between 2012 and 2018: An Observational Cross-Sectional Study

The prevalence of chronic diseases during pregnancy and adverse maternal obstetric outcomes in Switzerland has been insufficiently studied. Data sources, which reliably capture these events, are scarce. We conducted a nationwide observational cross-sectional study (2012−2018) using data from the Swiss Hospital Medical Statistics (MS) dataset. To quantify the recording of chronic diseases and adverse maternal obstetric outcomes during delivery in hospitals or birthing centers (delivery hospitalization), we identified women who delivered a singleton live-born infant. We quantified the prevalence of 23 maternal chronic diseases (ICD-10-GM) and compared results to a nationwide Danish registry study. We further quantified the prevalence of adverse maternal obstetric outcomes (ICD-10-GM/CHOP) during the delivery hospitalization and compared the results to existing literature from Western Europe. We identified 577,220 delivery hospitalizations, of which 4.99% had a record for ≥1 diagnosis of a chronic disease (versus 15.49% in Denmark). Moreover, 13 of 23 chronic diseases seemed to be substantially under-recorded (8 of those were >10-fold more frequent in the Danish study). The prevalence of three of the chronic diseases was similar in the two studies. The prevalence of adverse maternal obstetric outcomes was comparable to other European countries. Our results suggest that chronic diseases are under-recorded during delivery hospitalizations in the MS dataset, which may be due to specific coding guidelines and aspects regarding whether a disease generates billable effort for a hospital. Adverse maternal obstetric outcomes seemed to be more completely captured.

Materno-fetal iron transfer and the emerging role of ferroptosis pathways

A successful pregnancy and the birth of a healthy baby depend to a great extent on the controlled supply of essential nutrients via the placenta. Iron is essential for mitochondrial energy supply and oxygen distribution via the blood. However, its high reactivity requires tightly regulated transport processes. Disturbances of maternal-fetal iron transfer during pregnancy can aggravate or lead to severe pathological consequences for the mother and the fetus with lifelong effects. Furthermore, high intracellular iron levels due to disturbed gestational iron homeostasis have recently been associated with the non-apoptotic cell death pathway called ferroptosis. Therefore, the investigation of transplacental iron transport mechanisms, their physiological regulation and potential risks are of high clinical importance. The present review summarizes the current knowledge on principles and regulatory mechanisms underlying materno-fetal iron transport and gives insight into common pregnancy conditions in which iron homeostasis is disturbed. Moreover, the significance of the newly emerging ferroptosis pathway and its impact on the regulation of placental iron homeostasis, oxidative stress and gestational diseases will be discussed.

Gestational diabetes mellitus affects placental iron homeostasis: Mechanism and clinical implications

Clinical studies suggest that pregnant women with elevated iron levels are more vulnerable to develop gestational diabetes mellitus (GDM), but the causes and underlying mechanisms are unknown. We hypothesized that hyperglycemia induces cellular stress responses leading to dysregulated placental iron homeostasis. Hence, we compared the expression of genes/proteins involved in iron homeostasis in placentae from GDM and healthy pregnancies (n = 11 each). RT-qPCR and LC-MS/MS analyses revealed differential regulation of iron transporters/receptors (DMT1/FPN1/ZIP8/TfR1), iron sensors (IRP1), iron regulators (HEPC), and iron oxidoreductases (HEPH/Zp). To identify the underlying mechanisms, we adapted BeWo trophoblast cells to normoglycemic (N), hyperglycemic (H), and hyperglycemic-hyperlipidemic (HL) conditions and assessed Fe³⁺ -uptake, expression patterns, and cellular pathways involving oxidative stress (OS), ER-stress, and autophagy. H and HL induced alterations in cellular morphology, differential iron transporter expression, and reduced Fe³⁺ -uptake confirming the impact of hyperglycemia on iron transport observed in GDM patients. Pathway analysis and rescue experiments indicated that dysregulated OS and disturbed autophagy processes contribute to the reduced placental iron transport under hyperglycemic conditions. These adaptations could represent a protective mechanism preventing the oxidative damage for both fetus and placenta caused by highly oxidative iron. In pregnancies with risk for GDM, antioxidant treatment, and controlled iron supplementation could help to balance placental OS levels protecting mother and fetus from impaired iron homeostasis.

Prevalence of gestational diabetes mellitus in Europe: A meta-analysis

AIMS

Estimates of the prevalence of gestational diabetes vary widely. It is important to have a clear understanding of the prevalence of this condition to be able to plan interventions and health care provision. This paper describes a meta-analysis of primary research data reporting the prevalence of gestational diabetes mellitus in the general pregnant population of developed countries in Europe.

METHODS

Four electronic databases were systematically searched in May 2016. English language articles reporting gestational diabetes mellitus prevalence using universal screening in general pregnant population samples from developed countries in Europe were included. All papers identified by the search were screened by one author, and then half screened independently by a second author and half by a third author. Data were extracted by one author. Values for the measures of interest were combined using a random effects model and analysis of the effects of moderator variables was carried out.

RESULTS

A total of 3258 abstracts were screened, with 40 studies included in the review. Overall prevalence of gestational diabetes mellitus was 5.4% (3.8-7.8). Maternal age, year of data collection, country, area of Europe, week of gestation at testing, and diagnostic criteria were found to have a significant univariate effect on GDM prevalence, and area, week of gestation at testing and year of data collection remained statistically significant in multivariate analysis. Quality category was significant in multivariate but not univariate analysis.

CONCLUSIONS

This meta-analysis shows prevalence of GDM that is at the upper end of previous estimates in Europe.

Single abnormal value on 3-hour oral glucose tolerance test during pregnancy is associated with adverse maternal and neonatal outcomes: a systematic review and metaanalysis

OBJECTIVE DATA

The purpose of this study was to determine whether women with 1 abnormal value on 3-hour 100-g oral glucose tolerance test are at an increased risk for adverse pregnancy outcomes.

STUDY

Gestational diabetes mellitus is diagnosed by a 2-step method, with a 3-hour, 100-g oral glucose tolerance test that is reserved for women with an abnormal 1-hour, 50-g glucose challenge test. Although the increased maternal-fetal morbidity with gestational diabetes mellitus is well established, controversy remains about the risk that is associated with an isolated abnormal value during a 3-hour, 100-g oral glucose tolerance test.

STUDY APPRAISAL AND SYNTHESIS METHODS

Prospective and retrospective studies that evaluated the maternal and perinatal impact of 1 abnormal glucose value during a 3-hour, 100-g oral glucose tolerance test were identified with the use of computerized databases. Data were extracted and quantitative analyses were performed.

RESULTS

Twenty-five studies (7 prospective and 18 retrospective) that met criteria for metaanalysis included 4466 women with 1 abnormal glucose value on oral glucose tolerance test. Patients with 1 abnormal glucose value had significantly worse pregnancy outcomes compared with women with zero abnormal values with the following pooled odds ratios: macrosomia, 1.59 (95% confidence interval, 1.16-2.19); large for gestational age, 1.38 (95% confidence interval, 1.09-1.76); increased mean birthweight, 44.5 g (95% confidence interval, 8.10-80.80 g); neonatal hypoglycemia, 1.88 (95% confidence interval, 1.05-3.38); total cesarean delivery, 1.69 (95% confidence interval, 1.40-2.05); pregnancy-induced hypertension, 1.55 (95% confidence interval, 1.31-1.83), and Apgar score of <7 at 5 minutes, 6.10 (95% confidence interval, 2.65-14.02). There was also an increase in neonatal intensive care unit admission and respiratory distress syndrome. Similar results were seen that compared 1 abnormal glucose value to a population with a normal 1-hour 50-g glucose challenge test (normal glucose screen). With the exception of birthweight, outcomes of patients with 1 abnormal glucose value were similar to outcomes of patients with gestational diabetes mellitus.

CONCLUSION

Women with 1 abnormal value on 3-hour, 100-g oral glucose tolerance test have a significantly increased risk for poor outcomes comparable with women who have gestational diabetes mellitus.

Prevalence of gestational diabetes and risk of complications before and after initiation of a general systematic two-step screening strategy in Germany (2012-2014)

AIMS

Information on the prevalence of gestational diabetes mellitus is scarce on national and international level. On July 1st, 2013, a general two-step screening was implemented in Germany harmonizing gestational diabetes diagnoses. We aim to provide prevalence estimates for gestational diabetes and pregnancy-related complications for the large region of North Rhine for the 12 months before and after introduction of the general screening.

METHODS

Routine care data covering all outpatient diagnoses of more than 150,000 pregnancies per 12-month period in women aged 15-55 years was used to determine cases of gestational diabetes. Gestational diabetes diagnosis and pregnancy-related complications were assessed according to the International Statistical Classification of Diseases and Related Health Problems (ICD-10). Relative Risks for pregnancy-related complications were calculated in pregnancies with and without gestational diabetes.

RESULTS

Before the screening, diagnosis of gestational diabetes was made in 6.02% of pregnancies and in 6.81% after this date (other types of diabetes mellitus: 1.67% and 1.76% respectively). The prevalence of GDM increased with age and was highest at age 36-40 years (8.45%). The relative increase in prevalence after introduction of the screening was highest in the age group≤25 years (24.9%). The frequency of pregnancy-related complications such as hypertension, pre-eclampsia, cesarean section was increased in pregnancies with gestational diabetes in comparison to those without independent of observation period.

CONCLUSIONS

We found a high prevalence of gestational diabetes, which has relatively increased by 13.12% after the introduction of the general screening.