Strengths and limitations
The strengths of this study are the novel approach and the use of
high-quality prospective clinical and biobank data incorporating a large
number of early pregnancy biomarkers. To our knowledge, this is the
first study to investigate a range of metabolic and inflammatory-related
biomarkers in a multi-centre cohort of low-risk nulliparous women, by
ethnicity. The main limitation of this study was the relatively small
number of Indian participants in SCOPE. Stratification by ethnicity did
therefore not allow us to investigate the association between early
pregnancy biomarkers and adverse pregnancy outcome. We did, however,
observe remarkable differences in metabolic profile by ethnicity and
further research is therefore needed to investigate this relationship.
It should be noted that the reported mean values for some biomarkers may
be different than expected, as we did not exclude outliers from this
study; however, data was transformed prior to analysis and checked for
normality. Secondly, as Indian women are more likely to have various
types of anaemia and are more likely to be
vegetarian,42 it would have been helpful to
investigate the association between ferritin and biomarker profile.
Unfortunately ferritin testing was not routinely performed in the SCOPE
study, and only 37% of Indian women were tested. Similarly, over a
quarter of women were not routinely screened for GDM. Finally, while
biomarkers were significantly different between ethnicities, many were
correlated. This is to be expected as an inflammatory response
encompasses multiple pathways that lead to an overall adverse milieu,
which can consequently result in poor outcomes. Each biomarker,
therefore, is unlikely to exert influence on outcomes independently of
other biomarkers. The presented biomarker profiles rather show an
overall picture of inflammation and/or adverse metabolic health.