Strengths and Limitations
This study suffers from a number of limitations. First, its
cross-sectional design precludes any confirmation of causality. However,
it is implausible that cord blood gas status should have an influence on
abdominal musculature. Second, reductions in the sample size for some
variables could have prevented significance being reached for some
associations. The study also has some strengths that should be
highlighted. First, the measurement of gases in the arterial CB is the
gold standard for examining the acid-base status of the foetus. Second,
venous and arterial CB samples were taken to allow for better
interpretation of the results. Third, muscle thicknesses and the IRD
were measured by ultrasonography - a reliable and risk-free method for
pregnant women24. Finally, to the best of our
knowledge, this is the first study providing a comprehensive examination
of the associations shown by objectively measured abdominal muscle
thickness and the IRD, with cord blood gases at birth.