How much higher is the risk of birth defects with IVF?
The best evidence shows that babies conceived through IVF have a modestly increased risk of birth defects compared to babies conceived naturally. A large U.S. study of over 11 million births found that the rate of birth defects was 77 per 10,000 in IVF pregnancies versus 25 per 10,000 in spontaneous pregnancies — about three times higher [8]. A major Chinese cohort of over 130,000 pregnancies reported a 48% higher relative risk (adjusted relative risk 1.48) [1], and a population-based study in Beijing found a 43% higher risk after adjusting for other factors [5]. These numbers sound large, but the absolute risk is still low: most IVF babies are born healthy.
The increased risk appears to apply to specific types of defects. Several studies found higher rates of heart defects (especially cyanotic heart defects) [8], musculoskeletal problems [2][8], and genital/urinary defects like hypospadias [2][8]. One study also found a higher risk of cleft lip/palate [8]. Importantly, the risk of neural tube defects (like spina bifida) was not increased in the studies that looked at it [8][3].
Why is the risk higher? It's not just the technology.
The higher risk isn't solely due to the IVF procedure itself — it's partly driven by two other factors: the higher rate of twin and triplet pregnancies with IVF, and the underlying infertility of the parents. A large Chinese study found that having a multiple pregnancy (twins or triplets) accounted for about 25% of the extra birth defect risk associated with IVF [1]. Another Chinese cohort put that figure at 31% [4]. This is why many clinics now recommend single embryo transfer: the same study calculated that if every IVF pregnancy were a singleton, one birth defect could be avoided for every 52 IVF pregnancies [1].
The parents' infertility also plays a role. A study from Japan found that when the father had low sperm count (male subfertility), the risk of certain defects like hypospadias and heart defects was higher, even after accounting for whether IVF or ICSI was used [6]. A South Australian study showed that the usual pattern of birth defects increasing with maternal age was actually reversed in IVF/ICSI pregnancies — younger women having IVF had a higher risk than older women, suggesting that the reason for infertility (not just age) matters [7]. This means some of the risk is carried by the couple's biology, not the lab dish.
Does the type of treatment matter? (ICSI, IUI, frozen embryos, medications)
Yes, different treatments carry slightly different risks. Intracytoplasmic sperm injection (ICSI), where a single sperm is injected into the egg, has been linked to a higher risk of certain defects compared to standard IVF — especially hypospadias and heart defects — but this may be due to the underlying male infertility rather than the injection itself [6]. Interestingly, intrauterine insemination (IUI), a simpler and less invasive fertility treatment, also carries a similar increased risk of birth defects as IVF (about double the risk of natural conception), suggesting that infertility itself is a key factor [9][10].
The use of certain medications during IVF may also matter. One study found that using corticosteroids (like prednisolone) in the first trimester was linked to a higher risk of talipes (clubfoot), hypospadias, and undescended testicles [3]. Another study found that a specific ovulation induction regimen (GnRH antagonist) was associated with a 47% higher risk of birth defects [4]. However, these are smaller or single-study findings and need more research. Using frozen versus fresh embryos did not consistently change the risk across studies [2][10].
About These Sources
This answer is built on 10 peer-reviewed studies — published from 2006 to 2024, 1 from 2024 or later, 4 in Q1 journals, collectively cited 112 times — selected as the most relevant from 15 studies that passed quality screening, drawn from 91 papers retrieved from a database of over 500 million.
Sources used in this answer
Assisted reproductive technology and the risk of birth defects mediated by multifetal pregnancy: evidence from the China Birth Cohort Study
In a large Chinese cohort (132,386 pregnancies), IVF had a 48% higher risk of birth defects (adjusted RR 1.48), and 25% of that risk was mediated by multiple pregnancy; single embryo transfer could prevent one defect per 52 pregnancies.
The risks of birth defects and childhood cancer with conception by assisted reproductive technology
In a large U.S. population-based study (over 1.5 million children), IVF with autologous eggs increased the risk of several nonchromosomal birth defects (AORs 1.22–1.85), and children with birth defects had a higher risk of childhood cancer.
Exposure to corticosteroids in the first trimester is associated with an increased risk of urogenital congenital anomalies
In a retrospective Australian cohort (12,426 live births), first-trimester corticosteroid use during IVF/ICSI was associated with increased risk of talipes (IRR 4.30), hypospadias (IRR 5.90), and cryptorchidism (IRR 5.53).
Assisted reproductive technology and birth defects in a Chinese birth cohort study
In a Chinese prospective cohort (1,825 ART vs 3,483 spontaneous pregnancies), ART had a higher risk of birth defects at all follow-ups (13.9% vs 7.0% at 1 year); twinning mediated 31.1% of the risk.
Birth defects surveillance after assisted reproductive technology in Beijing: a whole of population-based cohort study
In a Beijing population-based cohort (2,699 ART vs 191,368 non-ART births), ART had a 43% higher adjusted risk of birth defects (aRR 1.43), especially chromosomal abnormalities in singletons to mothers under 35.
Male subfertility and the risk of major birth defects in children born after in vitro fertilization and intracytoplasmic sperm injection: a retrospective cohort study.
In a Japanese registry study of 59,971 singleton IVF/ICSI births, male subfertility (low sperm count) was associated with higher risks of hypospadias and heart defects, suggesting underlying infertility contributes to risk.
Maternal factors and the risk of birth defects after IVF and ICSI: a whole of population cohort study.
In a South Australian cohort (2,211 IVF, 1,399 ICSI, 301,060 natural births), the usual age-birth defect relationship was reversed in IVF/ICSI; younger women had higher risk, and maternal factors like nulliparity and anemia increased risk in ICSI.
The effect of assisted reproductive technology on the incidence of birth defects among livebirths.
In a U.S. cohort of 11.8 million live births (2011–2013), ART had a higher risk of birth defects (77 vs 25 per 10,000; OR 2.14), especially cyanotic heart defects (OR 2.74), cleft lip/palate (OR 1.47), and hypospadias (OR 1.77).
Similarly increased congenital anomaly rates after intrauterine insemination and IVF technologies: a retrospective cohort study.
In a French retrospective cohort, singletons conceived by IUI had a similar increased risk of major birth defects as those conceived by IVF (AOR 2.0 for both), compared to natural conception.
In vitro fertilization is associated with an increase in major birth defects.
In a U.S. academic center study (1,462 IVF, 343 IUI, 8,422 natural births), IVF had a 30% higher adjusted odds of major birth defects (AOR 1.30), while IUI showed a non-significant increase (AOR 1.11).