Table 3. Relationship between perinatal and prenatal risk factors and maternal susceptibility to submicroscopic P. falciparum infection at enrolment.

Variable	Sub-class	Submicroscopic P. falciparum infection			Adjusted P value
		% (n)	Unadjusted	OR [95%CI]
Age group (years)	≤ 20	28.1 (18)	X2 = 0.427; p = 0.808	0.48 [0.18–1.29]	0.146
	21–25	23.6 (17)		0.69 [0.30–1.56]	0.366
	> 25	24.4 (33)		Ref
Gravidity	Primigravidae	30.1 (25)	X2 = 2.103; p = 0.349	2.92 [1.19–7.18]	0.019
	Secundigravidae	26.6 (17)		2.07 [0.90–4.76]	0.070
	Multigravidae	21.3 (26)		Ref
Trimester of gestation	First	37.5 (3)	X2 = 1.738; p = 0.419	0.38 [0.04–4.01]	0.421
	Second	27.5 (36)		0.83 [0.39–1.79]	0.620
	Third	22.0 (29)		Ref
Ethnicity	Semi-bantu	23.0 (47)	X2 = 1.737; p = 0.187	0.59 [0.28–1.24]	0.162
	Bantu	31.6 (18)		Ref
History of fever	Yes	24.1 (63)	X2 = 2.558; p = 0.110	2.86 [0.74–11.11]	0.129
	No	45.5 (5)		Ref
IPTp-SP Use	Yes	16.9 (12)	X2 = 3.437; p = 0.064	0.12 [0.01–0.98]	0.048
	No	28.1 (52)		Ref
IPTp-SP Dosage	0	28.1 (52)	X2 = 4.743; p = 0.093	0.18 [0.02–1.73]	0.138
	1–2	11.1 (4)		0.68 [0.15–3.05]	0.611
	≥ 3	22.9 (8)		Ref
Bednet Use	Yes	22.7 (22)	X2 = 0.468; p = 0.494	1.51 [0.77–2.97]	0.232
	No	26.4 (46)		Ref
Maternal anaemia status	Anaemic	25.5 (40)	X2 = 0.094; p = 0.759	0.85 [0.44–1.63]	0.622
	Non anaemic	23.8 (25)		Ref

Values in parentheses denote total participants with valid values for this variable; Bold text indicate significant P values.