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Background— Maternal diabetes mellitus is associated with an increased risk of offspring congenital heart defects (CHD); however, the causal mechanism is poorly understood. We further investigated this association in a Danish nationwide cohort. Methods and Results— In a national cohort study, we identified 2 025 727 persons born from 1978 to 2011; among them were 7296 (0.36%) persons exposed to maternal pregestational diabetes mellitus. Pregestational diabetes mellitus was identified by using the National Patient Register and individual-level information on all prescriptions filled in Danish pharmacies. Persons with CHD (n=16 325) were assigned to embryologically related cardiac phenotypes. The CHD prevalence in the offspring of mothers with pregestational diabetes mellitus was 318 per 10 000 live births (n=232) in comparison with a baseline risk of 80 per 10 000; the adjusted relative risk for CHD was 4.00 (95% confidence interval, 3.51–4.53). The association was not modified by year of birth, maternal age at diabetes onset, or diabetes duration, and CHD risks associated with type 1 (insulin-dependent) and type 2 (insulin-independent) diabetes mellitus did not differ significantly. Persons born to women with previous acute diabetes complications had a higher CHD risk than those exposed to maternal diabetes mellitus without complications (relative risk, 7.62; 95% confidence interval, 5.23–10.6, and relative risk, 3.49; 95% confidence interval, 2.91–4.13, respectively; P =0.0004). All specific CHD phenotypes were associated with maternal pregestational diabetes mellitus (relative risk range, 2.74–13.8). Conclusions— The profoundly increased CHD risk conferred by maternal pregestational diabetes mellitus neither changed over time nor differed by diabetes subtype. The association with acute pregestational diabetes complications was particularly strong, suggesting a role for glucose in the causal pathway.

We thank Ziliang Ye and colleagues for their comments on our article, in which we reported associations between offspring congenital heart defects and maternal hypertensive disorders of pregnancy.1 They suggest 3 possible limitations that may have weakened our study. We contend that, although our study undoubtedly had limitations, those mentioned by Ye et al are not among them. First, Ye et al argue that our results may have been confounded by medication use, specifically the use of folic acid and vitamin B12 to prevent neural tube defects, and the use of medications to treat hypertensive …

Background— Pregnancy losses and atherosclerotic disease may be etiologically linked through underlying pathology. We examined whether miscarriage and stillbirth increase later risk of myocardial infarction, cerebral infarction, and renovascular hypertension. Methods and Results— Among women pregnant at least once between 1977 and 2008, we identified a cohort of women with miscarriages, stillbirths, or live singleton births. These women were followed from the end of pregnancy for incident myocardial infarction, cerebral infarction, and renovascular hypertension. Using Poisson regression, we estimated incidence rate ratios for each of the outcomes by history of miscarriage and stillbirth. Among 1 031 279 women followed for >15 928 900 person-years, we identified 27 98 myocardial infarctions, 40 53 cerebral infarctions, and 1269 instances of renovascular hypertension. Women with stillbirths had 2.69 (95% confidence interval, 2.06–3.50), 1.74 (1.32–2.28), and 2.42 (1.59–3.69) times the rates of myocardial infarction, cerebral infarction, and renovascular hypertension, respectively, as women with no stillbirths. Compared with women with no miscarriages, women with miscarriages had 1.13 (1.03–1.24), 1.16 (1.07–1.25), and 1.20 (1.05–1.38) times the rates of these same outcomes, respectively; these associations were dose dependent, with each additional miscarriage increasing the rates of myocardial and cerebral infarction and renovascular hypertension by 9% (3% to 16%), 13% (7% to 19%), and 19% (9% to 30%), respectively. Associations were strongest in younger women ( Conclusions— Pregnancy losses were associated with subsequent risks of myocardial infarction, cerebral infarction, and renovascular hypertension, consistent with either shared etiology or the initiation of pathological processes by a pregnancy loss leading to atherosclerosis.

Background: Both pregnant women carrying fetuses with heart defects and women with hypertensive disorders of pregnancy often exhibit angiogenic imbalances, suggesting that the same mechanisms are involved in the pathogenesis of the former and the pathophysiology of the latter. We conducted a register-based cohort study to determine whether offspring congenital heart defects are associated with an increased risk of hypertensive disorders of pregnancy and whether the mechanisms driving any association are primarily maternal or fetal. Methods: Among singleton pregnancies without chromosomal abnormalities lasting ≥20 weeks in Denmark from 1978 to 2011 (n= 1 972 857), we identified pregnancies complicated by offspring congenital heart defects or early preterm preeclampsia, late preterm preeclampsia, term preeclampsia, and gestational hypertension. We used polytomous logistic regression to estimate odds ratios (ORs) for associations between offspring congenital heart defects and maternal hypertensive disorders of pregnancy overall and for specific heart defects. Results: Offspring congenital heart defects were strongly associated with early preterm preeclampsia (OR, 7.00; 95% confidence interval [CI], 6.11–8.03) and late preterm preeclampsia (OR, 2.82; 95% CI, 2.38–3.34) in the same pregnancy and weakly associated with term preeclampsia (OR, 1.16; 95% CI, 1.06–1.27), but they were not associated with gestational hypertension (OR, 1.07; 95% CI, 0.92–1.25). Association strengths were consistent across heart defect types. Offspring congenital heart defects in a previous pregnancy were also strongly associated with preterm preeclampsia in subsequent pregnancies (early preterm preeclampsia: OR, 2.37; 95% CI, 1.68–3.34; late preterm preeclampsia: OR, 2.04; 95% CI, 1.52–2.75) but were only modestly associated with term preeclampsia and not associated with gestational hypertension. Similarly, preterm preeclampsia in a previous pregnancy, but not term preeclampsia or gestational hypertension, was associated with offspring congenital heart defects in later pregnancies (early preterm preeclampsia: OR, 7.91; 95% CI, 6.06–10.3; late preterm preeclampsia: OR, 2.83; 95% CI, 2.11–3.79; term preeclampsia: OR, 0.98; 95% CI, 0.88–1.10; gestational hypertension: OR, 1.13; 95% CI, 0.92–1.38). Conclusions: Linked pathophysiological mechanisms may be involved in some congenital heart defects and preterm preeclampsia. The strong associations across pregnancies support a predominantly maternal origin of effect.

Background— Knowledge of the familial contribution to congenital heart diseases (CHD) on an individual and population level is sparse. We estimated an individual’s risk of CHD given a family history of CHD, as well as the contribution of CHD family history to the total number of CHD cases in the population. Methods and Results— In a national cohort study, we linked all Danish residents to the National Patient Register, the Causes of Death Register, the Danish Central Cytogenetic Register, and the Danish Family Relations Database, yielding 1 763 591 persons born in Denmark between 1977 and 2005, of whom 18 708 had CHD. Individuals with CHD were classified by phenotype. We estimated recurrence risk ratios and population-attributable risk. Among first-degree relatives, the recurrence risk ratio was 79.1 (95% confidence interval [CI] 32.9 to 190) for heterotaxia, 11.7 (95% CI, 8.0 to 17.0) for conotruncal defects, 24.3 (95% CI,12.2 to 48.7) for atrioventricular septal defect, 12.9 (95% CI, 7.48 to 22.2) for left ventricular outflow tract obstruction, 48.6 (95% CI, 27.5 to 85.6) for right ventricular outflow tract obstruction, 7.1 (95% CI, 4.5 to 11.1) for isolated atrial septal defect, and 3.4 (95% CI, 2.2 to 5.3) for isolated ventricular septal defect. The overall recurrence risk ratio for the same defect was 8.15 (95% CI, 6.95 to 9.55), whereas it was 2.68 (95% CI, 2.43 to 2.97) for different heart defects. Only 2.2% of heart defect cases in the population (4.2% after the exclusion of chromosomal aberrations) were attributed to CHD family history in first-degree relatives. Conclusions— Specific CHDs showed highly variable but strong familial clustering in first-degree relatives, ranging from 3-fold to 80-fold compared with the population prevalence, whereas the crossover risks between dissimilar cases of CHD were weaker. Family history of any CHD among first-degree relatives accounted for a small proportion of CHD cases in the population.

Background— Recommendations for presymptomatic screening of relatives of cardiomyopathy patients are based on findings from tertiary centers. Cardiomyopathy inheritance patterns are fairly well understood, but how cardiomyopathy in younger persons ( Methods and Results— By linking Danish national register data, we constructed a cohort of 3.9 million persons born from 1950 to 2008. We ascertained family history of premature ( Conclusions— A family history of premature cardiomyopathy death was associated with an increase in risk of cardiomyopathy ranging from 6- to 400-fold, depending on age, kinship, gender and number of affected family members. Our general population-based results support recommendations for presymptomatic screening of relatives of cardiomyopathy patients.