A large Nordic study found children conceived through assisted reproductive technology had a higher risk of congenital heart defects compared to those conceived spontaneously.
The study, published in the European Heart Journal, analyzed data from over 7.7 million children born in Denmark, Finland, Norway, and Sweden between 1984 and 2015. Major congenital heart defects (CHDs) were detected in 1.84% of assisted reproductive technology (ART)-conceived children vs. 1.15% of spontaneously conceived children, and Severe CHDs occurred in 0.35% of ART children vs. 0.26% of spontaneously conceived children.
The risk of CHD was highest in multiples, regardless of conception method, and no significant difference in CHD risk was found between intracytoplasmic sperm injection (ICSI) and in vitro fertilization (IVF), and no significant difference between frozen and fresh embryo transfer.
Among ART-conceived singletons, 1.62% had major CHDs compared to 1.11% of spontaneously conceived singletons. Severe CHDs occurred in 0.31% of ART singletons vs. 0.25% of spontaneously conceived singletons. Multiples born after ART had a 2.47% risk of major CHDs. Spontaneously conceived multiples had a 2.41% risk.
Analysis of specific CHD types revealed increased risks in ART singletons for isomerism of atrial appendages, atrioventricular septal defect, and tetralogy of Fallot (AOR 1.34; 95% CI, 1.03-1.73; P = .028)
Researchers used the Committee of Nordic ART and Safety (CoNARTaS) cohort, cross-linking data from national ART registries, medical birth registries, national patient registries, cause of death registries, and population registries. The study included 171,735 children conceived through ART and 7,575,902 spontaneously conceived children.
Major CHDs were defined according to the European Concerted Action on Congenital Anomalies and Twins (EUROCAT) classification. Severe CHDs were identified using a subgroup of 26 major CHDs classified as severe by EUROCAT. Researchers also analyzed CHDs according to the hierarchical classification system developed by Botto et al.
The study timeline varied by country: Denmark (1994-2014), Finland (1990-2014), Norway (1984-2015), and Sweden (1987-2015). Follow-up for CHDs was up to 1 year of age, except for Norway, where data were available only at birth. ICD-8, ICD-9, and ICD-10 codes were used to identify CHDs. Stillbirths were excluded due to low data quality on birth defects.
The study relied on registry data and ICD codes, which may have the potential for miscoding. Information on CHDs in miscarriages, terminations, and stillbirths was not available. The study also lacked data on the causes of infertility and specific ART techniques used in Finland.
The authors declared having no competing interests.