Objective: Routine high-dose Fe supplementation in non-anaemic pregnant women may induce oxidative stress and eventually affect birth outcomes. The aim of the present study was to measure oxidative stress markers in pregnant women with low/normal and high Hb values in trimester 1 (Hb1) and to relate these to birth weight.
Design: A cross-sectional study where selected oxidative stress markers were analysed in both maternal (trimester 1; T1) and cord blood samples and correlated with birth weight.
Setting: A tertiary hospital in urban South India.
Subjects: One hundred women were chosen based on their Hb1 values (forty women with low/normal Hb1 (<110 g/l) and sixty women with high Hb1 (≥120 g/l)).
Results: In T1, women with high Hb1 values were found to have lower paraoxonase-1 (PON-1) activity (424·7 (sd 163·7) v. 532·9 (sd 144·7) pmol p-nitrophenol formed/min per ml plasma, P=0·002) and higher lipid peroxides compared with women with low/normal Hb1. Routine supplementation of Fe to these women resulted in persistent lower PON-1 activity in cord blood (P=0·02) and directionally lower (P=0·142) birth weights. Furthermore, women with high Hb1 who delivered low-birth-weight babies were observed to have lowest PON-1 activity in T1. No changes were observed in other markers (myeloperoxidase activity and total antioxidant levels).
Conclusions: Routine Fe supplementation in pregnant women with high Hb1 associated with increased oxidative stress, as reflected by low PON-1 activity in T1, could potentially lead to deleterious effects on birth weight.
Keywords: Birth outcomes; Hb; Low birth weight; Oxidative stress; Trimester 1.