Trends over time in congenital malformations in live-born children conceived after assisted reproductive technology

INTRODUCTION: Children born after assisted reproductive technology (ART), particularly singletons, have been shown to have an increased risk of congenital malformations compared with children born after spontaneous conception. We wished to study if there has been a change in the risk of major congenital malformations in children conceived after ART compared with children born after spontaneous conception during the latest decades?

MATERIAL AND METHODS: Population-based cohort study including 90 201 ART children and 482 552 spontaneous conception children born in Denmark, Finland, Norway and Sweden. Both singletons and twins born after in vitro fertilization, intracytoplasmatic sperm injection and frozen embryo transfer were included. The children were included from when the national Nordic ART registries were established until 2007. Multiple logistic regression analyses were used to estimate the risks and adjusted odds ratios for congenital malformations in four time periods: 1988-1992; 1993-1997; 1998-2002 and 2003-2007. Only major malformations were included.

RESULTS: The absolute risk for singletons of being born with a major malformation was 3.4% among ART versus 2.9% among spontaneous conception during the study period. The relative risk of being born with a major congenital malformation between all ART children and spontaneous conception children remained similar through all four time periods, p=0.39. However, we found that over time the number of children diagnosed with a major malformation increased in both groups across all four time periods.

CONCLUSION: When comparing children conceived after ART and spontaneous conception, the relative risk of being born with a major congenital malformation did not change during the study period. This article is protected by copyright. All rights reserved.