Table 4. Cuzick's trend test analysis of placental changes across ordered groups by number of P. vivax infections during pregnancy^†.

	Trend across infection groups (z)	P value
	(0 →1 →2+)a
Syncytial knotting	2.35	0.019
Syncytial rupture	1.59	0.112
Placental barrier thickness	2.63	0.008
Necrosis area	0.53	0.597
Intervillous space area	0.22	0.826
Mononuclear cells	1.67	0.096
Polymorphonucleates	1.43	0.154

^†Women were divided according to the number of P. vivax infections that were diagnosed microscopically during pregnancy.

^aCuzick's trend test was performed across the ordered groups: no P. vivax infection (0), one P. vivax infection (1) and two or more P. vivax infections (2+). (z) Measure and direction of tendency.