Rationale: It has been suggested that in pregnant women weekly iron supplements are as effective as daily supplements in preventing iron deficiency anaemia (IDA).
Objective: To compare the effectiveness of prophylactic antenatal oral iron supplements given weekly, thrice weekly and daily in preventing IDA in pregnancy.
Design: A randomised control trial.
Setting: University antenatal clinic, (UANC) Galle.
Subjects and method: An oral iron supplement containing 100 mg of elemental iron was randomly given weekly (n = 26) thrice weekly (n = 35) and daily (n = 31) to 92 women who were 14 to 24 weeks pregnant. Haemoglobin (Hb), serum ferritin (SF) and haematocrit (Hct) were assessed before and after 12 to 20 weeks of supplementation and a logistic regression analysis carried out.
Results: The risk of developing anaemia was significantly higher in the weekly (odds ratio 15, 95% CI 1.4-165.6, p < 0.03) and possibly higher in the thrice weekly (odds ratio 3, 95% CI 0.3-30.3, p = 0.3) groups. The risk of developing iron deficiency (SF < 12 micrograms/l) was also significantly higher in the weekly (odds ratio 18, 95% CI 2.8-115.5, p < 0.003) and thrice weekly (odds ratio 10, 95% CI 1.6-64.8, p < 0.02) groups.
Conclusion: Prophylactic oral iron supplements when given intermittently were not effective in preventing iron deficiency anaemia in pregnancy.