Can IVF or fertility treatments affect CHD rates? 

Yes, children conceived through assisted reproductive technology (ART), such as In Vitro Fertilisation (IVF), have a statistically higher risk of Congenital Heart Disease (CHD). Recent large-scale clinical data from 2024 indicates that the risk of major heart defects is approximately 36% higher in babies conceived via ART compared to those conceived naturally. While the absolute risk remains low affecting fewer than 2% of these infants  the association is consistent across various types of fertility treatments. 

The use of assisted reproductive technology has increased significantly worldwide, with millions of children now born through these methods. As the technology evolves, researchers have closely monitored the health outcomes of these infants. Understanding the link between fertility treatments and heart defects is a priority for both parents and clinicians. This article examines the latest 2024-2025 findings on CHD rates in IVF-conceived babies, the role of multiple births, and the clinical theories explaining why these risks exist. 

What We will cover in this Article 

• Statistical differences in CHD rates between ART and natural conception. 

• The impact of multiple births (twins/triplets) on cardiac risk. 

• Comparison of risks between IVF, ICSI, and fresh vs. frozen embryo transfers. 

• Biological theories: Parental subfertility vs. the ART process itself. 

• The role of prenatal medication exposure in fertility treatments. 

• Clinical recommendations for fetal heart screening in IVF pregnancies. 

CHD Prevalence in Assisted Reproduction 

According to a major study published in the European Heart Journal in September 2024, which analyzed over 7 million births in Nordic countries, the prevalence of major CHD is significantly higher in the ART population. The research found that major heart defects occurred in 1.84% of babies born after assisted reproduction, compared to 1.15% in those conceived naturally. 

The following table presents a comparison of absolute and relative risks based on 2024-2025 clinical data: 

Conception Method	Absolute Risk of Major CHD	Adjusted Odds Ratio (AOR)
Spontaneous Conception	1.15%	1.0 (Baseline)
Assisted Reproduction (ART)	1.84%	1.36 (36% increase)
ART Singleton Births	1.62%	1.25 (25% increase)
ART Multiple Births (Twins)	2.47%	1.70 (70% increase)

This data confirms that while most babies born through IVF are healthy, there is a small but statistically significant increase in the occurrence of structural heart issues that may require specialist surgery or long-term monitoring. 

Causes: Why Does ART Increase Cardiac Risk? 

The exact cause of the increased CHD risk in IVF pregnancies is still a subject of active research. Currently, clinical experts propose three primary theories: 

1. Parental Subfertility: The underlying reasons why a couple has difficulty conceiving (such as genetic factors or advanced maternal age) may also increase the likelihood of developmental issues like heart defects. 

2. The ART Process: The manipulation of eggs and embryos in a laboratory setting, including the use of culture media and hormonal stimulation, might influence early cellular signaling during the ‘critical window’ of heart formation. 

3. Medication Exposure: New research from January 2025 suggests that ART pregnancies often involve higher exposure to ‘Category D’ medications during the first trimester, which could potentially interfere with organogenesis. 

‘The fact that the risk of heart defects remains similar regardless of whether IVF or ICSI is used suggests that a common factor likely the parents’ underlying fertility status may play as large a role as the technology itself.’  Dr. Stefan Petrov 

Triggers: The Role of Multiple Births 

One of the strongest triggers for CHD in the ART population is the higher rate of multiple births (twins and triplets). Multiple gestations are naturally at a higher risk for many complications, including heart defects. Because IVF historically involved transferring multiple embryos to increase success rates, this significantly boosted the overall CHD statistics for the ART group. 

• Twin-to-Twin Interaction: In identical twin pregnancies, shared circulation can trigger imbalances in blood flow that affect heart development. 

• Placental Stress: The increased demand on the placenta in multiple pregnancies can lead to localized hypoxia, which may disrupt the formation of heart valves. 

• Clinical Shift: Modern ‘Single Embryo Transfer’ (SET) policies in the UK are designed to reduce these risks by minimizing the occurrence of multiples. 

Differentiation: Fresh vs. Frozen Embryo Transfers 

Expectant parents often ask if the method of embryo storage affects the baby’s heart. Clinical data from 2024 indicates that the risk of CHD is virtually identical between fresh embryo transfers and frozen-thawed embryo transfers. 

• Fresh Cycles: Involved in higher initial hormonal stimulation for the mother, which some theories suggest could affect the ‘environment’ of the uterus. 

• Frozen Cycles: While the freezing process is a physical stressor for the embryo, it allows the mother’s hormonal levels to return to a more natural state before transfer. 

• Outcome: Despite these differences, the rate of major heart defects remains consistent across both methods, reinforcing the theory that the risk may be tied to parental factors. 

To Summarise 

Assisted reproductive technology is associated with a 36% increase in the risk of major Congenital Heart Disease. While the absolute risk remains very low (less than 2 in 100 babies), the link is well-established in modern clinical research. The risk is notably higher in multiple births, leading many clinicians to recommend specialized fetal heart scans for these pregnancies. Most importantly, many children born through IVF are healthy and do not have cardiac issues. 

If you are concerned about your baby’s heart during an IVF pregnancy, discuss the possibility of a fetal echocardiogram with your midwife or consultant. 

If your baby shows signs of a heart problem, such as blue-tinted skin (cyanosis), difficulty breathing, or extreme lethargy, call 999 immediately. 

You may find our free Pregnancy Due Date Calculator helpful for tracking your developmental milestones and scheduling recommended prenatal screenings. 

Authority Snapshot (E-E-A-T Block) 

This article was reviewed by Dr. Stefan Petrov, a UK-trained physician (MBBS) with postgraduate certifications in ACLS and BLS. Dr. Petrov has extensive experience in general medicine and emergency care within hospital wards and intensive care units. He has contributed to medical education by developing patient-focused content that adheres to the latest clinical data from the European Society of Cardiology (ESC) and the NHS, ensuring accurate and safe information for those undergoing fertility treatments.