Discussion
In present study, we showed that diastolic dysfunction statistically
increases as the number of pregnancies increases. Additionally, cut of
value of parity for diastolic dysfunction was 6.5 which is higher than
other studies
[6,
12].
Previous studies showed that cardiovascular mortality increases along
with increased parity [7]. Changes in
the renin-angiotensin-aldosterone system explain this mechanism
[14]. Estrogen secreted by placenta
increases the release of angiotensinogen. Angiotensinogen produces
angiotensin-2 that activates the RAS system. RAS system induces sodium
and water retention. As a result, increased afterload is observed along
with pregnancy. Also decreased relaxin levels affect cardiovascular
mortality during pregnancy [15].
However, these changes continue only with pregnancy and their effects
after pregnancy are still not clear.
We also found that diastolic function deteriorates as the parity
increases. Aggarwal et al, performed the first known study on this issue
and they found the same results[16].
Other studies similarly showed that diastolic dysfunction increases with
the parity
[6,
12]. However; they performed these
studies up to 7 pregnancies (grand multiparity). In our study, women
that have a history of 9 and more pregnancies (great grand multiparity)
were also included. The present study has the highest number of parity
in the literature.
There is lack of evidence about relationship between the parity and the
severity of diastolic dysfunction. Kim et al. found that 2.5 and above
parity number significantly increases the diastolic
dysfunction[6]. Other study performed
by Keskin et al. showed that pregnancies of 4 and above significantly
increase the diastolic dysfunction
[12]. In our study, the cut-off value
for diastolic dysfunction severity according to the ROC curve analysis
was 6.5 pregnancies. This difference attributed to the number of
pregnancies included in this study is higher than other studies before.
Aortic stiffness is a prognostic risk factor for cardiovascular
mortality. In the present study, binary logistic regression analysis
showed that presence of hypertension and diabetes mellitus did not make
a significant difference in terms of diastolic dysfunction; however
number of pregnancies and age did make a significant difference. This
can be attributed to increasing of aortic stiffness. In our study, we
showed the same results as the previous studies in the
literature
[17-20].
In the present study, significant decrease in ejection fraction was
observed as the number of pregnancies increases. However, this decrease
did not reach the systolic dysfunction range (greater than %50).
Although Kim et al. found same results as ours; other studies did not
show this
correlation
[6, 12,
16]. This
result attributed to be exposed of long time diastolic dysfunction as
our study population has higher pregnancy numbers.