Similar asthma outcomes, but higher allergy rates, in ART-conceived children

Children conceived through assisted reproductive technology (ART) showed similar asthma outcomes but had a higher risk of allergies and slightly altered lung function compared with those who were born after spontaneous conception, according to a study presented at ESHRE 2022.

“Over 8 million children have been born after conception with ART worldwide. [However,] emerging evidence shows an increased risk of atopic disorders, such as asthma and allergies, in such children, potentially due to epigenetic alterations or underlying parental subfertility and perinatal risk factors ... [Therefore,] it is important to further investigate the risk of atopy in such offspring,” said Dr Laura Wijs from the University of Western Australia in Perth, Australia.

A total of 152 children from the GUHS* cohort who were born after ART (eg, in vitro fertilization [IVF] or intracytoplasmic sperm injection [ICSI]) comprised the ART group. They were compared with 1,845 spontaneously conceived offspring (non-ART group) from the RAINE** Generation 2 cohort to assess the percentage risk of asthma and allergies at 14 years of age by using ISAAC*** questionnaire, spirometry, Methacholine Challenge (MCh) test, and skin prick testing. [ESHRE 2022, abstract O-087]

After adjusting for sex, multiplicity, gestational age, and birthweight z-score, there was no difference in the rate of current asthma between the ART and non-ART groups (7.7 percent vs 10.8 percent, adjusted odds ratio [adjOR], 0.82; p=0.530). Wijs noted that these findings are “reassuring”.

With regard to allergy outcomes, there were significantly higher percentages of children in the ART group who had current hay fever (32.4 percent vs 25.2 percent; adjOR, 1.52; p=0.036), food allergy (20.7 percent vs 10.9 percent; adjOR, 1.89; p=0.010), and positive skin prick test (68.0 percent vs 45.4 percent; adjOR, 3.034; p<0.001) than the non-ART group.

“The higher prevalence of allergies [in ART-conceived children] could be based on the hygiene hypothesis with ART families as often being smaller, living in urban areas, and less microbial exposure,” Wijs explained. “[This] is of importance to families and healthcare providers and opens possibilities for targeted screening and treatment.”

In terms of lung function, the results were somewhat divergent, as reflected by the significantly higher FEV₁⁺ (mean 3.10 vs 2.96 L; p=0.011) and FVC⁺⁺ (mean 3.72 vs 3.29 L; p<0.001), with lower rates of FEV₁/FVC ratio (85.5 percent vs 91.8 percent; p<0.001) and MCh test positivity (8.8 percent vs 18.6 percent; p=0.006) in the ART vs the non-ART group.

Nonetheless, Wijs pointed out that the effect on lung function parameters may have been driven by differences in lung development in children.

“[Taken together, our findings suggest that] it is very important to keep investigating the long-term health of ART offspring, both for evidence-based advice for couples considering ART,” Wijs noted.

“[Our findings] require replication in larger studies, … potentially applying the siblingship design to further explore those underlying mechanisms [between ART and non-ART siblings],” she added.

*GUHS: Growing Up Healthy Study

**RAINE: Western Australian pregnancy cohort

***ISAAC: International Study of Asthma and Allergies in Childhood

⁺FEV₁: Forced expiratory volume in 1 second

⁺⁺FVC: Forced vital capacity