Is diabetes mellitus a teratogen or a coteratogen?

Risk of congenital heart defects in offspring exposed to maternal diabetes mellitus: an updated systematic review and meta-analysis

PURPOSE

A systematic review and meta-analysis was performed to assess the risk of congenital heart defects (CHDs) and its specific phenotypes associated with maternal diabetes mellitus (DM) including pregestational diabetes mellitus (PGDM) and gestational diabetes mellitus (GDM).

METHODS

PubMed, Embase, Medline, Google Scholar, Cochrane Libraries, China National Knowledge Infrastructure, Wanfang Database, Chinese Scientific Journals Fulltext Database and China Biology Medicine disc were searched from the inception dates to 15 December 2018, to identify case-control or cohort studies assessing the association between maternal DM and risk of CHDs. The exposure of interest was maternal DM; the outcomes of interest were CHDs and its specific phenotypes. Either a fixed- or a random-effects model was used to calculate the overall combined risk estimates. Subgroup analyses were performed to explore potential heterogeneity moderators.

RESULTS

Total 52 studies, which involved 259,917 patients with CHDs among 16,929,835 participants, were included for analysis. Overall, mothers with DM compared with those without DM had a significantly higher risk of CHDs in offspring [odds ratios (OR) = 2.71, 95% confidence intervals (CI) 2.28-3.23]. When data were restricted to different types of DM, a significantly increased risk of CHDs was observed among mothers with PGDM (OR = 3.18, 95% CI 2.77-3.65) and GDM (OR = 1.98, 95% CI 1.66-2.36). Our study suggested the risk of CHDs was significantly higher among mothers with PGDM than those with GDM. Additionally, this study suggested maternal DM was significantly associated with most phenotypes of CHDs; of these, double outlet of the right ventricle (OR = 10.89; 95% CI 8.77-13.53), atrioventricular septal defect (OR = 5.74; 95% CI 3.20-10.27) and truncus arteriosus (OR = 5.06; 95% CI 2.65-9.65) were identified as the first three of the most common phenotypes of CHDs associated with maternal DM.

CONCLUSIONS

The maternal DM including PGDM and GDM are significantly associated with risk of CHDs and its most phenotypes. The PGDM seems to be more likely to cause CHDs in offspring than GDM. Further studies are needed to clarify the underlying mechanisms.

Risk of birth defects associated with maternal pregestational diabetes

Maternal diabetes preceding pregnancy may increase the risk of birth defects in the offspring, but not all studies confirm this association, which has shown considerable variation over time, and the effect of having type 1 versus type 2 diabetes is unclear. We conducted a population-based cohort study in the Northern Italy Emilia-Romagna region linking administrative databases with a Birth Defects Registry. From hospital discharge records we identified all diabetic pregnancies during 1997-2010, and a population of non-diabetic parturients matched for age, residence, year and delivery hospital. We collected available information on education, smoking and drug prescriptions, from which we inferred the type of diabetes. We found 62 malformed infants out of 2,269 births among diabetic women, and 162 out of 10,648 births among non-diabetic women. The age-standardized prevalence ratio (PR) of malformation associated with maternal pregestational diabetes was 1.79 (95 % confidence interval 1.34-2.39), a value that varied little by age. Type of diabetes strongly influenced the PR, with higher values related to type 2 diabetic women. Most major subgroups of anomalies had PRs above 1, including cardiovascular, genitourinary, musculoskeletal, and chromosomal abnormalities. There was an unusually high PR for the rare defect 'extra-ribs', but it was based on only two cases. This study indicates that maternal pregestational type 2 diabetes is associated with a higher prevalence of specific birth defects in offspring, whereas for type 1 diabetic mothers, particularly in recent years, the association was unremarkable.

Congenital heart disease in pregnancies complicated by maternal diabetes mellitus. An international clinical collaboration, literature review, and meta-analysis

PURPOSE

Investigation of the incidence and distribution of congenital structural cardiac malformations among the offspring of mothers with diabetes type 1 and of the influence of periconceptional glycemic control.

METHODS

Multicenter retrospective clinical study, literature review, and meta-analysis. The incidence and pattern of congenital heart disease in the own study population and in the literature on the offspring of type 1 diabetic mothers were compared with the incidence and spectrum of the various cardiovascular defects in the offspring of nondiabetic mothers as registered by EUROCAT Northern Netherlands. Medical records were, in addition, reviewed for HbA(1c) during the 1st trimester.

RESULTS

The distribution of congenital heart anomalies in the own diabetic study population was in accordance with the distribution encountered in the literature. This distribution differed considerably from that in the nondiabetic population. Approximately half the cardiovascular defects were conotruncal anomalies. The authors' study demonstrated a remarkable increase in the likelihood of visceral heterotaxia and variants of single ventricle among these patients. As expected, elevated HbA(1c) values during the 1st trimester were associated with offspring fetal cardiovascular defects.

CONCLUSION

This study shows an increased likelihood of specific heart anomalies, namely transposition of the great arteries, persistent truncus arteriosus, visceral heterotaxia and single ventricle, among offspring of diabetic mothers. This suggests a profound teratogenic effect at a very early stage in cardiogenesis. The study emphasizes the frequency with which the offspring of diabetes-complicated pregnancies suffer from complex forms of congenital heart disease. Pregnancies with poor 1st-trimester glycemic control are more prone to the presence of fetal heart disease.

Effect of maternal diabetes and ethanol interactions on embryo development in the mouse

The aim of this study was to determine the possible fetal effects of interaction between maternal diabetes and acute doses of alcohol. Pregnant TO mice were made diabetic by a single injection of streptozotocin (STZ) on gestation day (GD) 2. Single dose of 0.003 or 0.03 ml/g body weight of fresh ethanol (25% v/v of absolute alcohol in normal saline) was injected into groups of diabetic and nondiabetic animals on GD 7 or 8. One group of diabetic animals had a daily dose of 6-8 IU of insulin subcutaneously. Fetuses were collected on GD 18. There was a significant increase in the incidence of implantation failure in the diabetes plus ethanol groups and insulin control group. Ethanol injection on GD 7 accentuated diabetes-related embryonic resorption and intrauterine growth retardation (IUGR). This effect was less marked in the diabetic group treated with ethanol on GD 8. Diabetes alone produced a greater incidence of IUGR than ethanol alone. Midfacial hypoplasia and minor anomalies were found more frequently in the combination treatment groups. Holoprosencephaly and thymus hypoplasia observed in diabetic groups were found to be reduced in frequency in the diabetes plus ethanol groups, suggesting an antagonistic type of ethanol-diabetes interaction, stage-dependently. Since severely malformed embryos are known to be resorbed/killed in utero in mice, this reduction might reflect the magnitude of early death of severely malformed embryos. These data suggest that the interaction effects are possibly related to alterations in fundamental developmental processes of early embryos.

Caudal dysplasia sequence: severe phenotype presenting in offspring of patients with gestational and pregestational diabetes

The association of maternal diabetes mellitus and congenital anomalies is well established. Children of insulin-dependent diabetic women have an increased risk of congenital malformations, especially major multiorgan defects. The cardiovascular, central nervous, gastrointestinal, genitourinary and musculoskeletal are the most affected body systems. Studies also show that offspring of women with gestational diabetes (specially those with fasting hyperglycaemia) tend to have higher rates of congenital anomalies. We report two cases of infants born to unrelated mothers: one with diabetes mellitus first detected during pregnancy (gestational diabetes) and the other with pregestational diabetes. Both infants had amelia of the lower limbs (suggestive of caudal dysplasia sequence), together with cardiovascular, skeletal, urinary and gastrointestinal defects. While pregestational diabetes seems to leave no doubt about its teratogenicity, the association of gestational diabetes and fetal/newborn malformations is still under discussion. Complete absence of the lower limbs has not been reported in association with gestational diabetes, but it may represent a spectrum of the caudal dysplasia sequence. The presentation of two cases with the same clinical phenotype of mothers with gestational and pregestational diabetes supports the evidence that gestational diabetes can be responsible for the development of the most severe form of the caudal dysplasia sequence.

Epidemiology of cardiovascular malformations: prevalence and risk factors

Epidemiological approaches to the study of cardiovascular malformations (CVMs) face challenges of disease definition, nomenclature, changing diagnostic methodologies, the rarity of the disease in the general population, and the incorporation of current knowledge on genetics and morphogenesis into designing studies to investigate risk factors and implement preventive strategies. Previous studies, especially the population-based Baltimore-Washington Infant Study, have documented variability in the prevalence of specific types of CVM by time, place, and personal characteristics and have highlighted the potential prevention of diabetes-associated heart malformations through timely medical management of pre-conception diabetes. Left-sided obstructive heart defects have been identified as targets for new studies of genetic risk factors. Potential environmental risk factors for CVMs also have been identified, such as organic solvents and pesticides, coincident with the emergence of new strategies to study genetic susceptibility and gene-environment interactions. Increased collaborative, multicenter research on these and other factors, such as nutritional factors in early pregnancy, offers new hope for potentially reducing the burden of CVM in the population.

Maternal diabetes: an independent risk factor for major cardiovascular malformations with increased mortality of affected infants

BACKGROUND

Intensive medical care of women with diabetes has reduced their risks of bearing infants with congenital anomalies. To assess the preventive potential of preconceptional care, the data of a population-based study of cardiovascular malformations (CVM) were analyzed to determine the morphogenetic specificity of maternal diabetes risks, the morbidity and mortality of the infants, and maternal characteristics that might affect these risks.

METHODS

The Baltimore-Washington Infant Study was a case-control study (1981-1989) that included all live born infants with confirmed CVM; control infants were a representative sample of the birth cohort. A questionnaire administered in home visits recorded parental information on social, medical, occupational, and environmental factors. For these analyses of preconceptional diabetes risks, the case group excluded chromosomal and mendelian disorders and was divided into 3 developmental categories and 12 diagnostic groups.

RESULTS

Preconceptional maternal diabetes was strongly associated with CVM of early embryonic origin (odds ratio [OR] = 4.7, 95% confidence interval [CI] 2.8-7.9) and with cardiomyopathy (OR = 15.1, 95% CI 5.5-41.3), but not with obstructive and shunting defects (OR = 1.4, 95% CI 0.7-3.0). There was heterogeneity within these developmental categories: among laterality defects, diabetes was associated only with cardiovisceral and atrioventricular discordance (OR = 10.0, 95% CI 3.7-27.0); among outflow tract anomalies, the risk was strongly associated with normally related great arteries (OR = 6.6, 95% CI 3.2-13.3) but not with simple transpositions; and among atrioventricular septal defects, diabetes was associated with the complete but not with the partial forms (OR = 22.8, 95% CI 7.4-70.5). The association in early CVM was strongest among infants with multisystem, predominantly VACTERL, anomalies. All-cause mortality of infants with CVM was 39% among those with diabetic mothers and 17.8% in those with nondiabetic mothers. Deceased infants of diabetic mothers were also more likely to have extracardiac anomalies (P = 0.041), to be born prematurely (P = 0.007), and to have low birth weight (P = 0.011). Multivariate analyses of maternal factors revealed no significant confounders of the diabetes associations.

CONCLUSIONS

The evidence of diabetes-induced major cardiac defects is of urgent clinical significance. The effectiveness of early preconceptional care in the prevention of congenital anomalies has been demonstrated repeatedly.

A prospective study of the risk of congenital defects associated with maternal obesity and diabetes mellitus

This study was designed to evaluate the effects of maternal obesity and diabetes mellitus on the risk of nonchromosomal congenital defects. We used data from 22,951 pregnant women enrolled in a prospective cohort study of early prenatal exposures and pregnancy outcome. The relative risks [prevalence ratios (PRs)] of major nonchromosomal congenital defects associated with obesity and diabetes, alone or in combination, were calculated using multiple logistic regression analysis. In this study, in the absence of diabetes, obese women (body mass index > or =28) had no higher risk, overall, of having an offspring with a major defect [PR = 0.95; 95% confidence interval (CI) = 0.62-1.5]. Their offspring, however, did have a higher prevalence of certain types of defects, including orofacial clefts; club foot; cardiac septal defects; and, to a lesser extent, hydrocephaly and abdominal wall defects. Women with pre-existing or gestational diabetes who were not obese also had no excess risk overall of having offspring affected by a major defect (PR = 0.98; 95% CI = 0.43-2.2), although they did have a higher prevalence of musculoskeletal defects. The pregnancies of women who were both obese and diabetic were 3.1 times as likely (95% CI = 1.2-7.6) to result in an offspring with a defect than were those of nonobese, nondiabetic women, which suggests that obesity and diabetes mellitus may act synergistically in the pathogenesis of congenital anomalies. The defects were largely craniofacial or musculoskeletal.

Epidemiological analysis of outcomes of pregnancy in gestational diabetic mothers

The association between maternal diabetes mellitus and congenital defects has been well documented. However, few data exist on the potential teratogenic effect of gestational diabetes (GD). We analyzed 19,577 consecutive infants with malformations of unknown cause and compared the offspring of mothers with GD with those of nondiabetic mothers. The children with each of 20 types of selected anomalies among the two groups were used to calculate the odds ratio (OR). Because we used as a reference group for each congenital defect the rest of malformed infants, the value of the OR gives us the specificity between the association of GD and each congenital defect. Our analysis strongly supports the suggestion that GD is a significant risk for holoprosencephaly, upper/lower spine/rib, and renal and urinary system anomalies. GD is a heterogeneous disorder, which includes previously unrecognized and newly diagnosed nongestational diabetes mellitus (DM). Thus, it is possible that the teratogenic effect is related to latent DM. However, because it is not possible at this time to differentiate between these situations, pregnancies complicated by GD should be considered at risk for congenital anomalies. Prenatal ultrasound examination should be aimed particularly at the detection of abnormalities of the central nervous system, the renal and urinary system, and the spine/rib developmental field.

Maternal diabetes: the risk for specific birth defects

We studied the risk for specific birth defects among infants of mothers with gestational and chronic diabetes using data collected by the Spanish Collaborative Study of Congenital Malformations (ECEMC). For the years 1976 to 1985, we identified 10,087 infants with malformations and 9,994 control infants; 155 of the case infants and 89 of the controls were born to diabetic mothers. The crude odds ratio for any minor or major defect and insulin-treated diabetes was 5.5 (95% CI = 1.2, 24.8), and for major malformations it was 8.7 (95% CI = 1.8, 34.7). The risk for defects involving the central nervous system (CNS), skeletal system and cardiovascular system were significantly increased. Infants of non-insulin-treated diabetic mothers were 2.9 times more likely to have a major congenital birth defect (95% CI = 1.2, 7.2). The crude odds ratio for any major or minor defect and mothers with gestational diabetes requiring insulin was 1.9 (95% CI = 1.1, 3.4). Similar risk was observed for major defects (OR = 1.9, 95% CI = 1.0, 3.7). These results suggest that infants of insulin-treated diabetic mothers have an increased risk of developing malformations of the CNS, cardiovascular system and skeletal system. We also found an increased risk for specific defect categories among infants of mothers with gestational diabetes treated with insulin.

Birth defects in the infants of aboriginal and non-aboriginal mothers with diabetes in Western Australia

OBJECTIVE

Because of the high prevalence of non-insulin-dependent diabetes in Australian Aborigines, and a suggestion that the prevalence of birth defects was high in the infants of Aboriginal mothers with gestational diabetes, this study was undertaken to determine the prevalence of birth defects in infants of Aboriginal and non-Aboriginal mothers with insulin-dependent, non-insulin-dependent, and gestational diabetes mellitus.

DESIGN

A retrospective cohort study of all births to diabetic and non-diabetic mothers in Western Australia, 1980-1984.

MAIN OUTCOME MEASURE

Birth defects diagnosed at any time up to the age of six years.

RESULTS

Compared with infants of non-diabetic, non-Aboriginal mothers, the prevalence ratio for birth defects in infants of non-Aboriginal insulin-dependent mothers was 2.08 (95% confidence interval, 1.2-3.7), and for infants of mothers with non-insulin-dependent diabetes the ratio was 3.64 (95% CI, 1.5-8.6). The corresponding ratios for infants of Aboriginal mothers were 4.85 (95% CI, 0.8-28.2) and 3.64 (95% CI, 1.3-10.4). For birth defects in infants of gestational diabetic mothers, the prevalence ratio was 1.07 (95% CI, 0.6-1.9) for the non-Aboriginal group and 3.65 (95% CI, 2.3-6.0) for the Aboriginal group. Diabetes could have accounted for 0.14% of birth defects in infants of non-Aboriginal mothers and for 4.62% in infants of Aboriginal mothers.

CONCLUSIONS

The excess of birth defects in infants of Aboriginal women with gestational diabetes may be due to non-insulin-dependent diabetes that predates the pregnancy but is only diagnosed during pregnancy. For Aboriginal infants, maternal diabetes may be the single most common known cause of birth defects that is amenable to change.

New multiple congenital anomalies syndrome in a stillborn infant of consanguinous parents and a prediabetic pregnancy

We report on a term stillborn female infant with multiple congenital anomalies (MCA) which have not previously been reported as occurring together. The malformations include a first and second branchial arch sequence, ectopia cordis with congenital heart defect, caudal "regression" sequence with absent sacrum and hypoplastic right femur, ectrodactyly, left radial abnormality, islet cell hyperplasia, and skin lesions. The pregnancy was complicated by abdominal cramping with exercise, heavy vaginal bleeding, maternal obesity, and a normal screening glucose tolerance test at 6 months gestation. The infant was born to 20-year-old G3P1SAB2 Mexican-American parents who are first cousins. There was strong maternal family history of adult-onset diabetes. The malformations have some findings in common with those seen in infants of diabetic mothers. Structural defects similar to, but not inclusive of, those in our infant have been reported in 2 sibs born to a prediabetic mother with a first cousin marriage as well as in focal dermal hypoplasia. Parental consanguinity is suggestive of an autosomal recessive disorder. Alternatively, it may represent a combined multifactorial effect making the conceptus more sensitive to metabolic teratogens and thus placing it at increased risk for disruption of normal development.

Maternal diabetes and cardiovascular malformations: predominance of double outlet right ventricle and truncus arteriosus

Most studies on the relationship of maternal diabetes to cardiovascular malformations (CVM) have been prospective investigations of pregnancy outcome and therefore could not identify associations with rare cardiac lesions. The results of a retrospective study shed new light on the risks of specific cardiac defects in diabetic pregnancies. The Baltimore-Washington Infant Study, a population-based case-control investigation of CVM, provides information on maternal diabetes reported in personal interviews. Among 2259 mothers of cases, 35 (1.5%) reported diabetes present before pregnancy (called "overt") and 95 (4.2%) reported diabetes only during pregnancy (called "gestational"). Among 2,801 mothers of controls, 14 (0.5%) had overt diabetes and 83 (3.0%) had gestational diabetes. Malformation-specific risks were expressed as odds ratios (OR) with 99.5% confidence intervals (CI). The strongest associations with overt maternal diabetes were found with double outlet right ventricle (OR 21.33; 99.5% CI 3.34, 136.26), and truncus arteriosus (OR 12.81; 99.5% CI 1.43, 114.64). No significant diagnosis-specific associations were found with gestational diabetes. Non-cardiac malformations were present in 23% of infants with CVM whose mothers had overt diabetes and in 26% of infants with CVM whose mother had gestational diabetes, in 32% of infants with CVM whose mothers did not have diabetes, and in 4% of controls. Double outlet right ventricle and truncus arteriosus are malformations dependent upon neural-crest-cell-derived ectomesenchymal tissues; these are precisely the conotruncal abnormalities that result from experimental ablation of the neural crest in chick embryos. The association with diabetes suggests a further etiologic link between these two lesions.

First-trimester hemoglobin A1 and risk for major malformation and spontaneous abortion in diabetic pregnancy

The relationship between the level of hemoglobin A1 (Hb A1) in the first trimester and major malformations and spontaneous abortions was examined in 303 insulin-requiring diabetic gravidas. During the study period, all patients with insulin-requiring diabetes mellitus antedating pregnancy who registered for prenatal care prior to 12 weeks' gestation and who had a known outcome were included. Thirty-five percent of the patients entered with a first-trimester Hb A1 of greater than 11.0% of total hemoglobin (9 standard deviations above the mean for a nondiabetic population). A broad spectrum of glycemic control was therefore represented. The risk of spontaneous abortion was 12.4% with first-trimester Hb A1 less than or equal to 9.3% and 37.5% with Hb A1 greater than 14.4% (risk ratio 3.0; 95% confidence interval 1.3-7.0). The risk for major malformation was 3.0% with Hb A1 less than or equal to 9.3% and 40% with Hb A1 greater than 14.4% (risk ratio 13.2; 95% confidence interval 4.3-40.4). Although the risks for both adverse outcomes were markedly elevated following a first trimester in very poor metabolic control, there was a broad range of control over which the risks were not substantially elevated. To keep malformations and spontaneous abortions to a minimum among diabetic women does not require "excellent" control; there seems to be a fairly broad range of "acceptable" control.

Does the severity of diabetic retinopathy predict pregnancy outcome?

The authors sought to determine whether the severity of diabetic retinopathy is a predictor of subsequent pregnancy outcome. One hundred and seventy-nine pregnant diabetic women were evaluated in their first trimester of pregnancy. Stereoscopic color photographs of the ocular fundus were taken and graded by the Fundus Photography Reading Center. Thirty-nine women had no retinopathy, while 28 had proliferative retinopathy in the worse eye. The women's history and hospital delivery room charts were reviewed with regard to pregnancy outcome. Thirty-three pregnancies terminated with an adverse outcome. A logistic regression analysis was used to evaluate significant predictors of pregnancy outcome. Of maternal age, duration of diabetes, glycosylated hemoglobin, proteinuria, cigarette smoking status, and severity of diabetic retinopathy, only the last variable significantly predicted an adverse outcome. These data suggest that the severity of retinopathy should be considered when counseling a pregnant diabetic woman.