Pregestational diabetes is associated with adverse outcomes in twin pregnancies: a regional register-based study

Clinical Factors for Predicting Pharmacotherapy in Twin Pregnancies Complicated by Gestational Diabetes Mellitus

Controlling blood glucose levels is the main target in pregnant women with gestational diabetes mellitus (GDM). Twin pregnancies are offered the same screening selection and have the same diagnostic criteria as well as treatment of gestational diabetes as singleton pregnancies, even though the risks for pregnancy complications are increased. The aim of this study was to assess the association between predicting factors, OGTT glucose levels and pharmacotherapy requirements in twin pregnancies with GDM. This retrospective cohort study included 446 GDM patients with twin pregnancies (246 managed with lifestyle modifications and 200 requiring pharmacotherapy) over a time period of 18 years. An evaluation of maternal characteristics and a standardized 75 g oral glucose test (OGGT) for glucose concentrations at fasting, 1 h and 2 h were conduced. OGTT glucose levels at fasting (=0 min, p < 0.01) and 1 h (p < 0.01) were significantly associated with the later requirement of pharmacotherapy. Also, clinical risk factors (pre-pregnancy BMI p < 0.01, multiparity p < 0.05, GDM in previous pregnancy p < 0.01, assisted reproduction p < 0.05) showed a predictive accuracy for insulin therapy in twin pregnancies complicated by GDM, whereas age and chorionicity had no effect. OGTT glucose measures in addition to clinical risk factors are promising variables for risk stratification in mothers with GDM and twin pregnancy.

Glycemic and nonglycemic mechanisms of congenital malformations in hyperglycemic pregnancies: a narrative review

Congenital malformations are more frequently found among children born to mothers with diabetes than in the background population. There are several complex mechanisms involved in the development of congenital malformations in the offspring of mothers with hyperglycemia, such as the overexpression of glucose transporters (GLUTs) 1 and 2, the increased activity of the hexosamine biosynthetic pathway and the reduced expression of the PAX3 gene with a consequent increase in p53 protein expression. These alterations can lead to increased glucose and free radical concentrations in the embryo, thus promoting the process of apoptosis and causing malformation. The most frequent malformations found in the offspring of mothers with diabetes are heart and neural tube defects, urinary tract and kidney malformations, and cleft lip with or without cleft palate. Strict glycemic control should be obtained before and during pregnancy, aiming to avoid or minimize the risk of congenital malformations in the offspring. Beyond hyperglycemia, several factors may also be associated with increased risks of malformations in the offspring of these women, such as obesity, multiple pregnancies, advanced maternal age, folic acid deficiency, use of angiotensin converting enzyme inhibitors and angiotensin receptor blockers, assisted reproduction techniques, and exposure to different types of environmental pollutants.

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.

Trends in Prevalence of Diabetes among Twin Pregnancies and Perinatal Outcomes in Catalonia between 2006 and 2015: The DIAGESTCAT Study

The aims of our study were to evaluate the trends in the prevalence of diabetes among twin pregnancies in Catalonia, Spain between 2006 and 2015, to assess the influence of diabetes on perinatal outcomes of twin gestations and to ascertain the interaction between twin pregnancies and glycaemic status. A population-based study was conducted using the Spanish Minimum Basic Data Set. Cases of gestational diabetes mellitus (GDM) and pre-existing diabetes were identified using ICD-9-CM codes. Data from 743,762 singleton and 15,956 twin deliveries between 2006 and 2015 in Catalonia was analysed. Among twin pregnancies, 1088 (6.82%) were diagnosed with GDM and 83 (0.52%) had pre-existing diabetes. The prevalence of GDM among twin pregnancies increased from 6.01% in 2006 to 8.48% in 2015 (p < 0.001) and the prevalence of pre-existing diabetes remained stable (from 0.46% to 0.27%, p = 0.416). The risk of pre-eclampsia was higher in pre-existing diabetes (15.66%, p = 0.015) and GDM (11.39%, p < 0.001) than in normoglycaemic twin pregnancies (7.55%). Pre-existing diabetes increased the risk of prematurity (69.62% vs. 51.84%, p = 0.002) and large-for-gestational-age (LGA) infants (20.9% vs. 11.6%, p = 0.001) in twin gestations. An attenuating effect on several adverse perinatal outcomes was found between twin pregnancies and the presence of GDM and pre-existing diabetes. As a result, unlike in singleton pregnancies, diabetes did not increase the risk of all perinatal outcomes in twins and the effect of pre-existing diabetes on pre-eclampsia and LGA appeared to be attenuated. In conclusion, prevalence of GDM among twin pregnancies increased over the study period. Diabetes was associated with a higher risk of pre-eclampsia, prematurity and LGA in twin gestations. However, the impact of both, pre-existing diabetes and GDM, on twin pregnancy outcomes was attenuated when compared with its impact on singleton gestations.