Strengths and limitations
Though socio-demographic factors could influence iron deficiency status,
the reduced gap between pregnancies was the only significant risk factor
identified. The finding of this study was compatible with other studies
such as the one by Lazović and Pocekovac(18).
Haemoglobin on its own is a poor indicator of iron deficiency, and
previous studies have emphasised its poor sensitivity for identifying
iron deficiency(19,20). Since the number of women with
LID was high, reflecting an overall high incidence in the population, it
is important to have easily assessable and affordable tests to screen
for iron deficiency. Due to the high cost and low availability of the
serum ferritin estimation method, the red cell indices, RDW, and blood
film were considered as substitute screening tests. However, the
correlation of red cell indices with LID did not show any statistical
significance. This may be due to the counter effects of pregnancy
induced changes, especially the MCV, as it increases by 4 fl with
progression of pregnancy(21). A study by Tiwari et al.
among 100 pregnant women in India supported these
findings(21).
It is known that few microcytes can be seen in the blood film in
LID(22). This could contribute to the increase in
RDW(16,23). Though the study by Tiwari et al.(21) had shown no significant indicators to detect
LID, our data showed a significant increase of RDW in the LID group.
Blood film morphology observed by three haematologists revealed that
hypochromic microcytic red cells and pencil cells were present in a
significant number of participants with LID. These two tests (blood film
and RDW) can be used independently or in combination as routine tests to
screen for LID. The use of ROC cut off values for red cell indices to
detect LID has been shown by Rabindrakumar et al.(4),
with a smaller number (70) of participants. However, such results were
not reflected in the analysis of the present study, even with a larger
sample size of 194.
Due to logistical constraints, the study has one limitation: subjects
could not be followed-up with to monitor their pregnancy outcome.