TABLE 1.

Participants' characteristics

	RIF n = 145	Control n = 21	P‐value
Age (years), mean ± SD	38.3 ± 4.2	32.0 ± 4.0	.68 × 10−9
Body mass index (kg/m2), mean ± SD	21.1 ± 2.8	21.2 ± 2.7	.92
Smoking, n (%)	2 (1.4)	1 (4.8)	.28
Pregnancy history, mean ± SD
Gravidity	0.8 ± 1.3	0.1 ± 0.3	.01
Parity	0.1 ± 0.3	0	.14
Causes of infertility, n (%)
Male factor	11 (7.6)	21 (100)	.22 × 10−17
Polycystic ovarian syndrome	5 (3.4)	0	.39
Endometriosis	19 (13.1)	0	.08
Tubal factor	13 (9.0)	0	.15
Unexplained infertility	100 (69.0)	0	.41 × 10−11
Previous history of ET, mean ± SD
No of ET cycles	6.0 ± 4.6	0.3 ± 0.6	.46 × 10−7
No of transferred embryos	8.1 ± 7.2	0.4 ± 0.7	.29 × 10−5
No of ET cycles using morphologically good embryos	3.4 ± 2.1	0.1 ± 0.5	.34 × 10−10
No of transferred morphologically good embryos	4.0 ± 2.7	0.1 ± 0.5	.73 × 10−9
Nugent score, mean ± SD	1.9 ± 2.7	0.9 ± 1.6	.09
≥7 (Bacterial vaginosis), n (%)	16 (11.9)	0 (0)	.13

Nugent score is often used for the diagnosis of bacterial vaginosis. Bacterial vaginosis is diagnosed as the score 7‐10.

Abbreviations: ET, embryo transfer; RIF, repeated implantation failure; SD, standard deviation.