Study suggests parental fertility issues, not IVF, influence child neurodevelopmental traits

A major US study indicates that parental subfecundity, rather than IVF itself, may be associated with small increases in behavioural difficulties, autism-related traits, and ADHD in children, highlighting underlying fertility issues as a key factor.

A large US study is adding weight to the argument that the fertility problems some parents face, rather than IVF itself, may be behind small differences seen in some children’s neurodevelopment. Researchers reported that children born after parental subfecundity were somewhat more likely to show behavioural difficulties, autism-related traits and, in some cases, an autism spectrum disorder diagnosis, while IVF showed no clear independent link with those outcomes.

The paper, published online in JAMA Network Open on 8 June 2026, analysed 15,382 mother-child pairs in the National Institutes of Health’s Environmental Influences on Child Health Outcomes cohort. The children had been conceived between 1998 and 2022 and were assessed between the ages of two and 10. ECHO said the data came from 44 sites across the US, including Puerto Rico, and that the analysis excluded pregnancies involving donor eggs or sperm as well as adopted children; where there had been twins or other multiples, only one child per pregnancy was included.

Rather than treating infertility treatment as a single exposure, the researchers separated families into several groups: natural conception without subfecundity, natural conception after subfecundity, conception after non-IVF treatment and conception after IVF. Subfecundity was defined broadly, including an infertility diagnosis or treatment history, repeated miscarriage, or trying to conceive for 12 months without success. Non-IVF treatment covered approaches such as ovulation-inducing medication and intrauterine insemination. To assess children, the team used established caregiver questionnaires for externalising and internalising problems and for autism-like social traits, alongside reports of clinician diagnoses of autism spectrum disorder and attention-deficit/hyperactivity disorder.

The strongest pattern centred on the parents’ fertility history rather than the procedure used to achieve pregnancy. In the full cohort, parental subfecundity was linked to higher externalising behaviour scores and higher social responsiveness scores, a measure of autism-like traits. The estimated increase in externalising problems was 0.47 points, while the increase in social responsiveness score was 1.08 points. Children of parents with subfecundity also had higher odds of an autism diagnosis overall, with an odds ratio of 1.27, and the association remained when the researchers looked only at children conceived naturally, with an odds ratio of 1.31. The authors said the score differences were “small and likely not clinically relevant”.

A separate signal emerged for non-IVF treatment. Children conceived that way had higher odds of ADHD than children conceived naturally, whether the comparison group involved families with a history of subfecundity or those without it. The odds ratio was 1.77 against the former group and 1.54 against the latter. The paper’s abstract, as indexed by PubMed, underlined that this comparison held against both natural-conception groups, strengthening the argument that the ADHD finding cannot be explained simply by lumping all fertility difficulties together. By contrast, the researchers found no statistically significant association between IVF and autism, ADHD or the questionnaire-based behavioural measures.

That distinction matters because fertility treatment use has grown, while earlier studies often struggled to tease apart treatment effects from the health conditions that led couples to seek help in the first place. ECHO said previous work had frequently been too small, had not followed children for long enough, or had failed to distinguish clearly between infertility and treatment. Linda Kahn of NYU Langone Health said in follow-on reports that “infertility treatment itself is not independently associated with child neurodevelopment outcomes”, arguing that underlying fertility problems were the more plausible driver.

The authors were careful not to overstate the findings. The full sample contained autism-enriched cohorts, which pushed the autism diagnosis rate to 7.6%, higher than in the general population. In the smaller subset of cohorts with detailed treatment-type data, the autism rate was 3.5% and the ADHD rate 6.3%. Some of the most eye-catching associations also weakened in sensitivity checks: in complete-case analyses, the links between subfecundity and both autism diagnosis and autism-like trait scores were no longer seen. The study also pointed to possible selection bias, noting that access to infertility diagnosis and treatment is uneven in the US and may track with access to developmental assessment.

There were also clues that pregnancy factors may be part of the pathway. Gestational age appeared to mediate the associations between subfecundity and both externalising behaviour and autism-like traits, though not the autism diagnosis itself. IVF pregnancies in the cohort had the shortest average gestation, at 36.9 weeks, and the highest rate of multiple birth, at 18.6%, compared with 38.4 weeks and 1.5% respectively among children conceived naturally without subfecundity. Even so, the paper did not find a clear IVF-specific neurodevelopmental effect after adjustment.

One possible explanation for the non-IVF and ADHD finding is the reason those treatments were prescribed. The researchers said the result may reflect confounding by indication, singling out polycystic ovary syndrome. In their data, PCOS was recorded in 49% of mothers in the non-IVF treatment group and 31% in the IVF group, compared with 11% among those who conceived naturally after subfecundity and 3% among those without subfecundity. The next step, the authors said, is to identify which underlying fertility problems, and which reasons for treatment, are most closely tied to later developmental differences in children.