Excess risk of preterm birth with periconceptional iron supplementation in a malaria endemic area: analysis of secondary data on birth outcomes in a double blind randomized controlled safety trial in Burkina Faso

Table 4 Placental pathology by preterm/term and AGA/SGA categories

Placental pathology n/N (%)^a	n	Term	Preterm	Relative risk (95% CI)	P	Adjusted relative risk (95% CI)	P ^b_adj
Acute malaria	181	10/150 (6.7)	2/31 (6.5)	0.97 (0.26; 3.62)	0.97	0.99 (0.27; 3.66)	0.99
Chronic malaria	181	35/150 (23.3)	13/31 (41.9)	2.00 (1.06; 3.78)	0.039	1.49 (0.75; 2.94)	0.26
Past malaria	181	81/150 (54.0)	15/31 (48.4)	0.83 (0.44; 1.58)	0.57	1.08 (0.56; 2.08)	0.82
Chorioamnionitis grade 3	179	11/148 (7.4)	2/31 (6.5)	0.88 (0.23; 3.32)	0.85	1.00 (0.25; 4.00)	0.99
Chorioamnionitis grades 2 and 3	179	67/148 (45.3)	13/31 (41.9)	0.89 (0.46; 1.72)	0.73	0.96 (0.49; 1.87)	0.90

Placental pathology n/N (%)^a	n	AGA	SGA	Relative risk (95% CI)	P	Adjusted relative risk (95% CI)	P ^b_adj
Acute malaria	179	7/115 (6.1)	5/64 (7.8)	1.18 (0.58; 2.39)	0.66	1.03 (0.53; 1.99)	0.94
Chronic malaria	179	30/115 (26.1)	17/64 (26.6)	1.02 (0.65; 1.59)	0.95	0.80 (0.50; 1.27)	0.32
Past malaria	179	63/115 (54.8)	32/64 (50.0)	0.88 (0.60; 1.31)	0.54	1.06 (0.71; 1.57)	0.80
Chorioamnionitis grade 3	177	9/114 (7.9)	4/63 (6.3)	0.86 (0.37; 1.99)	0.70	1.02 (0.45; 2.27)	0.97
Chorioamnionitis grades 2 and 3	177	54/114 (47.4)	26/63 (41.3)	0.85 (0.57; 1.28)	0.43	1.04 (0.70; 1.54)	0.86

AGA appropriate for gestational age, SGA small for gestational age
^aAcute: only parasites and minimal hemozoin deposition in the macrophages but not fibrin; Chronic: parasites and Hemozoin deposition; Past: hemozoin usually mixed with fibrin but no parasites. Severity of acute chorioamnionitis and funiculitis (acute histologic chorioamnionitis) was graded histologically as early (grade 1), intermediate (grade 2) and advanced (grade 3) following the Redline-classification [17, 18]
^bAdjusted for birth month

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