Table 2. The prevalence of vaginal microorganisms in each trimester.

Microorganisms		1st trimester (n=221)	2nd trimester (n=138)	3rd trimester (n=234)	P-valuea)	P-valueb)
Abnormal vaginal colonization		48 (21.7)	29 (21.0)	34 (14.5)	0.130	0.048
Gram-negative bacteria		18 (8.1)	7 (5.1)	6c) (2.6)	0.028	0.008
	Escherichia coli	14 (6.3)	5 (3.6)	4 (1.7)	0.038	0.011
	Enterobacteriae	1 (0.5)	0 (0.0)	0 (0.0)	0.605	0.243
	Klebsiella pneumonia	2 (0.9)	2 (1.4)	1 (0.4)	0.646	0.570
	Pseudomonas aeruginosa	1 (0.5)	0 (0.0)	0 (0.0)	0.605	0.243
Gram-positive cocci		26 (11.8)	13 (9.4)	12 (5.1)	0.038	0.012
	Staphylococcus aureus	4 (1.8)	2 (1.4)	2 (0.9)	0.665	0.377
	Streptococcus agalactiae	10 (4.5)	7 (5.1)	7 (3.0)	0.556	0.402
	Enterococcus faecalis	1 (0.5)	0 (0.0)	0 (0.0)	0.605	0.243
	Other gram-positive cocci	11 (5.0)	4 (2.9)	3 (1.3)	0.071	0.022
Candida		16 (7.2)	13 (9.4)	20 (8.5)	0.759	0.619

Values are presented as number (%).P-values less than 0.05 are shown in bold.

^a)Fisher's exact test was used to compare the prevalence of vaginal microorganisms in each trimester; ^b)Linear by linear association analysis was used to check trend according to each trimester; ^c)In one case, the identification of the specific microorganism was failed even with the presence of Gram-negative bacteria.