Strengths and limitations
Limitations of our study need to be considered. First, inclusion of
participants from our Kingston cohort required retrospective analysis of
placentas that were originally submitted to Pathology for examination.
This aspect of the study design may have resulted in selection bias, as
although PE is an indication for pathology examination, not all
placentas are sent.50 We did observe a significant
difference in several important pregnancy parameters between our study
sites, including blood pressure at delivery, anti-hypertensive use at
delivery and gestational age at delivery. These differences may be due
to placenta pathology referral practices, as it is likely that placentas
from women with more severe PE disease are more frequently selected for
submission to pathology (and thus available for inclusion in our study).
As cardiovascular parameters were similar between our cohorts at the 6
month postpartum clinic visit, we do not feel these delivery parameters
influenced our findings. Due to our small sample size, we may be
underpowered to detect differences between low and high-risk groups for
less common pathology, such as chronic inflammation. Confirming our
results in an adequately powered prospective study may identify a
predictive combination of placental lesions that robustly identifies
high priority women for postpartum CVD screening at the time of
delivery. Our study is strengthened by the standardised placental
evaluations we conducted using our evidence-based synoptic data
collection.33 Variability in placenta pathology
examination is a known challenge and the use of this synoptic collection
form ensures each placenta was evaluated in a reproducible manner.