Cardiorespiratory fitness and muscle strength in offspring conceived through assisted reproductive technologies: results from the Munich heARTerY-study

TL;DR

This study finds that children conceived through assisted reproductive technologies may have lower cardiorespiratory fitness compared to naturally conceived children.

Contribution

This is the first study to compare cardiorespiratory fitness and muscle strength in children conceived via assisted reproductive technologies versus naturally conceived children.

Findings

ART participants had significantly lower estimated VO2max and pulse rate recovery compared to controls.

No significant differences in muscle strength were observed between the two groups.

Adjustments for age, birthweight, and gestational age confirmed the differences in cardiorespiratory fitness.

Abstract

Children conceived through assisted reproductive technologies (ART) potentially display an increased cardiovascular morbidity. Despite cardiorespiratory fitness (CRF) and muscle strength being key indicators of cardiovascular outcomes, they have not been investigated in ART offspring yet. This observational pilot cohort study aimed to evaluate CRF and muscle strength in ART participants and spontaneously conceived controls. Anthropometric variables, diet quality, level of physical activity, and sedentary behavior were evaluated. Participants performed a 6-min walking test (6MWT) and a 20-m shuttle run test (20mSRT). 6MWT distance and the number of archived laps were assessed, the maximal oxygen uptake (V̇O2max) was estimated, and pulse rate recovery was calculated. Maximal hand grip strength (HGS) was determined as a marker of muscle strength. Generalized linear models were used to adjust data for age, birthweight, and gestational age. Sixty-seven ART participants and 86 spontaneously conceived peers were included. Both groups did not differ significantly in age (11.3 (IQR 8.1–18.2) vs. 11.9 (IQR 8.7–18.3) years), gender ratio, anthropometric variables, diet quality, level of physical activity and sedentary behavior. The amount of 20mSRT laps (Padj=0.02), estimated VO2max (45.0 (IQR 37.9–47.1) vs. 45.8 (IQR 43.1–48.0) ml·kg⁻1·min⁻1, Padj=0.04), and pulse rate recovery (Padj=0.03) were significantly lower in ART participants after adjustment. HGS did not differ between groups.

Conclusion: This study indicates a significantly lower CRF in ART participants. Significant differences in muscle strength were not demonstrated between groups. Future studies should validate these results by using cardiopulmonary exercise testing for VO2max assessment.

What is Known:

• Children conceived through assisted reproductive technologies (ART) potentially display an increased cardiovascular morbidity. Cardiorespiratory fitness (CRF) and muscle strength, despite being major cardiovascular determinants, have not been assessed within the ART population yet.

What is New:

• This observational pilot cohort study describes and compares CRF and muscle strength in ART participants and spontaneously conceived controls.

The online version contains supplementary material available at 10.1007/s00431-025-06261-y.