Table 1

Characteristics of women at recruitment by availability of delivery data and group allocation, proportions % (numbers)

Delivery data (n=2258)No delivery data (n=2068)
CharacteristicsSelective iron (1149) % (n)Routine iron (1109) % (n)Selective iron (993) % (n)Routine iron (1075) % (n)
Maternal age, mean (SD) years24.6 (5.4)24.7 (5.3)25.0 (5.6)24.6 (5.6)
Maternal age (years) (categorised)
 <2017.5 (201)16.5 (183)15.7 (156)19.3 (207)
 20–2441.1 (472)39.9 (443)39.0 (387)37.1 (399)
 25–2923.1 (265)23.3 (258)23.9 (237)23.4 (252)
 30–3411.3 (130)13.8 (153)12.9 (128)13.3 (143)
 ≥356.3 (72)5.6 (62)7.4 (74)6.5 (70)
 Missing0.8 (9)0.9 (10)1.1 (11)0.4 (4)
Haemoglobin by HemoCue (g/dl), mean (SD)9.6 (1.7)9.6 (1.7)
Haemoglobin by HemoCue (g/dl), n (%)
 <7.06.9 (79)6.2 (62)
 7.0–8.9024.6 (283)25.4 (252)
 9.0–9.9023.5 (270)24.4 (242)
 10.0–10.9021.9 (252)21.1 (210)
 11.0–11.9014.1 (162)13.7 (136)
 ≥ 12.07.9 (91)8.4 (83)
 Not measured1.0 (12)0.8 (8)
Previous abortions
 No87.6 (1007)86.8 (963)86.0 (854)85.4 (918)
 Yes12.1 (139)12.8 (142)13.6 (135)14.5 (156)
 Missing0.3 (3)0.4 (4)0.4 (4)0.1 (1)
Gestational age, mean (SD) weeks21.6 (5.9)21.7 (5.6)21.0 (5.9)21.3 (5.8)
Gestational age (categorised)
 <1619.2 (221)16.4 (182)21.5 (213)20.1 (216)
 17–2021.8 (250)24.2 (268)22.5 (223)21.7 (233)
 21–2634.3 (394)32.6 (361)31.3 (311)33.7 (362)
 >2719.7 (226)19.7 (219)17.5 (174)18.2 (196)
 No information58 (5.0)7.1 (79)7.3 (72)6.3 (68)
Previous stillbirths
 No91.5 (1052)92.3 (1024)91.6 (910)91.0 (978)
 Yes8.2 (94)7.2 (80)7.9 (78)8.9 (96)
 Missing0.3 (3)0.5 (5)0.5 (5)0.1 (1)
Previous deliveries
 None29.7 (341)30.3 (336)29.2 (290)33.8 (363)
 One31.9 (367)31.7 (352)30.6 (304)28.5 (306)
 Two19.2 (221)17.8 (197)17.9 (178)18.6 (200)
 Three or more18.8 (216)19.8 (220)22.0 (218)19.0 (205)
 Missing0.4 (4)0.4 (4)0.3 (3)0.1 (1)
HIV status
 Negative81.2 (934)81.8 (907)76.7 (762)79.0 (849)
 Positive18.8 (215)18.2 (202)23.3 (231)21.0 (226)
Twin pregnancy
 No98.7 (1134)98.6 (1093)99.2 (985)99.2 (1066)
 Yes1.3 (15)1.4 (16)0.8 (8)0.8 (9)
Symptoms during current pregnancy before first prenatal visit
Fever
 Yes22.9 (264)24.4 (271)28.8 (286)23.8 (256)
Headache
 Yes41.5 (477)43.5 (482)44.3 (440)43.0 (462)
Cold/chills
 Yes18.0 (207)18.4 (204)20.6 (205)18.8 (202)
Vomit/nausea
 Yes27.5 (316)26.9 (298)29.8 (296)28.6 (307)
Body aches
 Yes21.8 (251)21.3 (237)23.8 (236)23.3 (251)
Self-reported malaria
 Yes5.7 (66)6.0 (67)5.9 (59)6.3 (68)
Had malaria test
 Yes7.0 (80)7.1 (79)8.0 (79)7.9 (85)