An analysis of 35 studies includes 604,641 fetuses and children conceived through IVF or ICSI: congenital heart defects were found in 2.62%, compared with 1.44% after natural conception.
Adjusted odds were 1.53 times higher. Researchers emphasize that the absolute risk remains low and that evidence is insufficient to recommend additional fetal echocardiography solely because a pregnancy was conceived through ART.
After a hard-won pregnancy through in vitro fertilization (IVF), another worry can begin: could a baby conceived through IVF be more likely to have a congenital anomaly than a naturally conceived baby? As parents prepare for a detailed prenatal ultrasound, their baby’s heart is one particular source of concern.
How different is the risk in practice?
A large study has compared more than 600,000 children conceived through assisted reproductive technology (ART), including IVF and intracytoplasmic sperm injection (ICSI), with more than 42 million naturally conceived children.
The systematic review and meta-analysis was published in the international journal Human Reproduction Update on September 17. The researchers combined 35 previously published studies to examine congenital heart defects (CHDs) in 604,641 fetuses and children conceived through ART and 42,021,027 conceived naturally. It is the largest meta-analysis of this question to date.
Before “1.53 Times,” Look at 2.62% and 1.44%
The results showed that congenital heart defects were observed more often in ART pregnancies. Across 29 cohort studies, the pooled prevalence of congenital heart defects was 2.62% among children conceived through ART and 1.44% among those conceived naturally. Put simply, the pooled estimates were about 2.6 in every 100 children after ART and about 1.4 in every 100 after natural conception.
However, this should not be immediately interpreted as “IVF treatment increases heart defects by 1.18 percentage points.” These figures were obtained by separately pooling prevalence estimates from observational studies conducted in different countries, periods, and populations. The difference between the two figures does not, by itself, represent the additional risk caused by ART.
The researchers therefore went beyond a simple comparison of occurrence rates and repeated the analysis while accounting for factors that could affect the risk of heart defects, such as maternal age. Combining data from 15 studies involving 33,019,895 individuals, they found that, even after accounting for these factors, the odds of a congenital heart defect being detected were approximately 1.5 times higher among children conceived through ART, including IVF, than among those conceived naturally.
The difference was somewhat greater for major congenital heart defects, which may require surgery or other active treatment.
Even after accounting for potentially influential factors such as maternal age, the odds of a major heart defect being detected were approximately 1.8 times higher among children conceived through ART than among those conceived naturally.
For relatively minor heart defects, there was a trend toward increased risk, but considerable uncertainty remained. Only two studies were available for this analysis, leaving insufficient evidence to conclude that minor heart defects also truly increase.
There is an important point for patients to keep in mind. The relative figure of “1.53 times” can make the risk appear substantially higher, but the actual frequency—the absolute risk—remains low. The researchers explicitly emphasized this in their findings.
Is ICSI Riskier? No Clear Difference Was Found
Could the method of fertilization make a difference? Patients who undergo ICSI, in which a single sperm is selected and injected directly into an egg, may be particularly concerned that it could be riskier for their child than conventional IVF.
The researchers examined this question separately. They found no statistical evidence that the association with congenital heart defects differed between IVF and ICSI. The same was true for fresh and frozen embryo transfer. Analyses separating singleton pregnancies from multiple pregnancies, including twins, also found no evidence that the association between ART and heart defects was significantly stronger in either group.
This study therefore does not support statements that “ICSI causes more heart defects than IVF” or that “frozen embryo transfer is safer than fresh embryo transfer in terms of heart defects.”
Is IVF Treatment Itself Really the Cause?
This is where the study’s most important question begins. Observing more congenital heart defects among children conceived through ART is not the same as showing that ART treatment itself caused those defects.
Couples who undergo IVF and couples who conceive naturally may differ from the outset. Women using ART may be older on average, and pregnancy risk factors such as obesity and underlying medical conditions may be distributed differently. Above all, the possibility that the male or female infertility factors that made conception difficult are themselves associated with a child’s health cannot be ruled out.
All adjusted analyses in this study accounted for maternal age. However, the extent of adjustment for other factors—such as congenital heart disease in the parents, maternal body mass index (BMI), smoking, and infertility-related diagnoses—varied across studies.
The researchers also noted that most previous studies had not adequately assessed the causes of infertility. As a result, they could not fully separate the effects of treatment from the effects of the parents’ underlying infertility and associated factors.
The 35 studies were not uniform in quality, either. They differed in how they defined congenital heart defects, selected participants, and adjusted for confounding variables, and there was considerable heterogeneity between their results. These findings therefore provide strong evidence of an association, but do not establish that IVF or ICSI directly causes heart defects.
Does an IVF Pregnancy Always Require Fetal Echocardiography?
“If I became pregnant through IVF, do I need more heart testing than other pregnant women?”
The researchers’ conclusion is more cautious than might be expected.
Although an increased risk of congenital heart defects was observed in ART pregnancies, the absolute prevalence remained low. The researchers explained that, in healthcare settings where standard fetal anomaly screening is performed in the second trimester, current evidence is insufficient to support additional fetal echocardiography for every pregnant woman solely because conception occurred through IVF.
This does not mean that fetal echocardiography is unnecessary. Separate risk factors, such as a family history, certain maternal medical conditions, or abnormal fetal findings, may warrant a detailed assessment of the fetal heart based on clinical judgment. The question addressed by this study is more specifically whether an ART pregnancy, on its own, warrants additional testing.
Reducing this study to the statement “babies conceived through IVF have a 1.53-fold higher risk of heart disease” would leave out a crucial part of the picture. Across 35 studies, a statistical association was clearly observed between ART pregnancies and congenital heart defects, including major heart defects. However, the absolute frequency remained low, and no clear differences were identified between IVF and ICSI or between fresh and frozen embryo transfer.
Above all, an unresolved question remains: current research cannot readily distinguish how much of the observed increase is attributable to ART itself and how much arises from the parents’ infertility, age, genetic factors, and health.
For parents with an IVF pregnancy, “1.53 times” is therefore not the only figure to remember. The absolute frequencies—2.62% after ART and 1.44% after natural conception—need to be considered alongside the fact that the reasons for the difference are not yet fully understood. That is the most accurate message this large study offers to people experiencing infertility.
This article is based on the systematic review and meta-analysis “Congenital Heart Defects in Children Conceived by Assisted Reproductive Technology: A Systematic Review and Meta-analysis,” published online in Human Reproduction Update on September 17, 2026, by researchers from Rigshospitalet, Copenhagen University Hospital, Denmark, and the University of Sydney, Australia. The review included 35 studies, comparing 604,641 fetuses and children conceived through ART with 42,021,027 conceived naturally. Article number: dmag028. DOI: 10.1093/humupd/dmag028. PMID: 42754249. PROSPERO registration number: CRD42025626281.
This article presents recent research findings. It is not a substitute for medical diagnosis or treatment, an assessment of an individual’s pregnancy or childbirth risks, or a recommendation for a particular test.
The image used in this article was created using generative artificial intelligence (ChatGPT, OpenAI). Any people depicted are fictional and do not represent real individuals.
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