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.