Table 2.

Subgroup analysis of primary/secondary infertility by year of studies

		Number of studies	Pooled proportion (95% CI)	Heterogeneity (I2, p-value)
Year of studies (PI)	Before 2000	3	36.75 (11.08–62.45)	96.7%, p < 0.001
	2000–2004	2	51.88 (26.4-77.36)	98.8%, p < 0.001
	2005–2009	5	50.08 (33.34–66.83)	98.4%, p < 0.001
	2010–2014	4	47.28 (24.2-70.36)	98.2%, p < 0.001
	2015–2019	6	57.26 (43.45–71.06)	98.7%, p < 0.001
Year of studies (SI)	Before 2000	3	63.25 (37.55–88.94)	96.7%, p < 0.001
	2000–2004	2	48.12 (22.64–73.6)	98.8%, p < 0.001
	2005–2009	5	49.92 (32.96–66.88)	98.5%, p < 0.001
	2010–2014	4	52.97 (30.58–75.36)	98.1%, p < 0.001
	2015–2019	6	41.55 (28.92–54.19)	98.4%, p < 0.001

PI primary infertility, SI secondary infertility, CI confidence interval