Muscle Strength and Cardiorespiratory Fitness in Minors Conceived through Assisted Reproductive Technologies: Insights from the Munich heARTerY Study

Background: More than 200,000 children are conceived through assisted reproductive technologies (ART) every year in Europe. In the literature, an altered vascular function in the ART offspring is discussed. Within the general population, elevated vascular morbidity is associated with lower cardiorespiratory fitness. This study aimed to evaluate whether minors conceived through ART show reduced muscle strength and cardiorespiratory fitness compared to spontaneously conceived peers.

Method: For the current analysis, study participants between 8 and 17 years were included. Subjects conceived through ART and naturally conceived peers were invited for an overall fitness assessment. The KIDMED questionnaire was used to assess diet quality. Physical activity was evaluated in accordance with WHO recommendations. Percentiles of body mass index were acquired in all study participants. Hand-grip strength was measured as a surrogate of muscle strength. The Progressive Aerobic Cardiovascular Endurance Run Test was applied to assess cardiorespiratory fitness. VO₂ max was calculated according to Matsuzaka et al. Data are presented as median (range) if non-normally distributed. To test for significance, the unpaired t-test or the Mann–Whitney U-test was used. The Pearson correlation coefficient was utilized for normally distributed variables and the Spearman correlation coefficient for non-normally distributed variables. A p-value <0.05 was defined as significant.

Results: For this study, 32 ART subjects (16 females) and 44 spontaneously conceived peers (21 females) were included. Both groups did not differ significantly in age (11.13 [8.10–17.93] years vs. 11.56 [8.06–17.83] years, p = 0.507), diet quality or physical activity. Solely within the ART-group, VO₂ max tended to correlate negatively with age (r = −0.314, p = 0.080). No significant differences were assessed in hand grip strength (17.75 [6.00−44.00] kg vs. 20.00 [12.00–45.00] kg, p = 0.219) and VO₂ max (45.42 [35.97–48.42] mL/kg/min vs. 45.73 [35.15–57.29] mL/kg/min, p = 0.521) between ART subjects and spontaneously conceived peers.

Conclusion: The results of this study indicate that minors conceived through ART display similar muscle strength and cardiorespiratory fitness compared to spontaneously conceived peers. However, VO₂ max tended to correlate negatively with age in the ART-group. Interestingly, preliminary results of our department revealed a significantly lower cardiorespiratory fitness in ART-adults. Hence, ART subjects might face increased cardiovascular risk in later life.

Publication History

Article published online:
28 January 2023