Table 2.

Primary outcomes of the enrolled studies.

Study	Sample size		Semen volume (mL)		Sperm concentration (106/mL)		Total count (106)
	High	Low	High	Low	High	Low	High	Low
Selevan, 2000	47	162	2.2 ± 1.3	2.0 ± 1.1	60.1 ± 46.7	59.9 ± 64.3	129.1 ± 103.1	113.5 ± 130.7
De Rosa, 2003	85	85	2.5 ± 0.9	2.7 ± 0.9	32.4 ± 22.1	33.7 ± 14.7	NM	NM
Rubes, 2005	36	36	3.0 ± 1.7	3.3 ± 1.5	81.6 ± 42.09	92.1 ± 79.0	234.2 ± 141.1	278.1 ± 245.4
Guven, 2008	38	35	3.2 ± 1.3	3.4 ± 1.4	44.6 ± 36.3	70.9 ± 50.0	NM	NM
Boggia, 2009	100	64	NM	NM	34.3 ± 20.3	37.3 ± 11.7	NM	NM
Rubes, 2010	47	47	3.2 ± 1.3	3.2 ± 1.3	134.2 ± 84.1	150.8 ± 84.6	NM	NM
Calogero, 2011	36	32	NM	NM	24.1 ± 15.4	99.2 ± 56.7	64.9 ± 43.3	240.6 ± 111.4
Zhou, 2014	429	917	2.3 ± 1.1	2.5 ± 1.4	79.4 ± 46.2	77.4 ± 44.6	NM	NM
Wu, 2016	367	349	NM	NM	39.4 ± 29.1	42.0 ± 30.3	104.4 ± 82.9	102.6 ± 96.4
Liu, 2017	370	327	NM	NM	39.4 ± 27.3	43.1 ± 31.1	108.4 ± 82.0	114.7 ± 96.0
Lao, 2018	535	501	NM	NM	40.6 ± 2.5	41.9 ± 2.3	NM	NM
Study	Progressive motility (PR, %)		Total motility (PR + NP, %)		Normal morphology (%)		SCSA-DFI (%)
	High	Low	High	Low	High	Low	High	Low
Selevan, 2000	32.5 ± 13.2	36.2 ± 17.1	41.6 ± 40.4	50.6 ± 79.6	13.2 ± 6.5	19.8 ± 8.5	28.8 ± 20.4	19.2 ± 12.2
De Rosa, 2003	12.3 ± 11.0	28.7 ± 4.6	34.7 ± 20.2	56.8 ± 7.4	NM	NM	NM	NM
Rubes, 2005	NM	NM	68.3 ± 12.1	62.7 ± 21.6	8.4 ± 2.6	11.3 ± 6.1	15.4 ± 12.6	13.5 ± 9.8
Guven, 2008	54.7 ± 23.6	70.3 ± 15.6	NM	NM	NM	NM	NM	NM
Boggia, 2009	15.0 ± 7.4	31.0 ± 5.3	37.0 ± 11.2	60.4 ± 6.3	NM	NM	NM	NM
Rubes, 2010	58.0 ± 9.9	58.1 ± 9.4	70.5 ± 8.2	74.4 ± 8.3	21.3 ± 9.8	18.8 ± 7.2	12.4 ± 5.8	10.1 ± 4.8
Calogero, 2011	12.4 ± 8.7	27.7 ± 6.9	29.6 ± 12.8	51.8 ± 10.2	17.2 ± 0.8	20.1 ± 0.6	9.3 ± 0.9	4.5 ± 0.4
Zhou, 2014	51.7 ± 17.5	52.3 ± 17.5	69.8 ± 20.9	71.0 ± 20.4	23.5 ± 11.5	30.2 ± 12.3	NM	NM
Wu, 2016	38.8 ± 17.7	37.0 ± 22.1	45.8 ± 20.6	44.6 ± 25.4	NM	NM	NM	NM
Liu, 2017	38.9 ± 19.6	38.6 ± 19.9	45.9 ± 22.5	46.3 ± 22.8	NM	NM	NM	NM
Lao, 2018	48.4 ± 15.4	46.9 ± 15.3	65.3 ± 14.0	66.4 ± 13.7	67.9 ± 15.2	71.8 ± 13.7	NM	NM

NM: not mentioned.