Table 2 Associations between proportion of pregnancy under the protection of IRS and outcomes measured at birth

Placental blood positive for malaria parasites by LAMP^a

 Risk

22/131 (16.8 %)

1/88 (1.1 %)

1/61 (1.6 %)

 aOR^b (95 % CI)

Reference group

0.03 (0–0.25)

0.05 (0.01–0.41)

 P value

0.001

0.006

Any evidence of placental malaria by histopathology^a

 Risk

63/132 (47.7 %)

25/88 (28.4 %)

17/62 (27.4 %)

 aOR^b (95 % CI)

Reference group

0.77 (0.35–1.69)

0.63 (0.27–1.48)

 P value

0.51

0.29

Moderate-high grade pigment deposition by histopathology^a

 Risk

37/132 (28.0 %)

11/88 (12.5 %)

9/62 (14.5 %)

 aOR^b (95 % CI)

Reference group

0.52 (0.20–1.36)

0.54 (0.20–1.47)

 P value

0.18

0.23

 Risk

28/134 (20.9 %)

9/90 (10.0 %)

2/65 (3.1 %)

LBW (<2500 g)

 aOR^b (95 % CI)

Reference group

0.29 (0.12–0.75)

0.08 (0.02–0.39)

 P value

0.01

0.002

 Risk

23/134 (17.2 %)

3/90 (3.3 %)

1/65 (1.5 %)

Pre-term delivery (<37 weeks)

 aOR^b (95 % CI)

Reference group

0.13 (0.03–0.53)

0.05 (0.01–0.43)

 P value

0.005

0.006

Fetal/neonatal deaths

 Risk

10/134 (7.5 %)

1/90 (1.1 %)

0/65 (0 %)

 aOR^b (95 % CI)

Reference group

0.10 (0–0.86)

0 (n/a)

 P value

0.03

0.03