Table 1.
WHO reference values for human semen characteristics and summary of studies investigating effects of aging on semen parameters
| Semen volume | Sperm count | Sperm concentration | Viability | Motility | Morphologically normal forms | Study population (age) | Reference |
|---|---|---|---|---|---|---|---|
| 1.5 ml (1.4–1.7) |
39 million (33–46 × 106) | 15 million/ml (12–16 × 106) | 58 % (55–63) |
32 % progressive motility (31–34) 40 % total (progressive + non-progressive) motility (38–42) |
4.0 % (3.0–4.0) | 4500 fertile men | WHO (2010) Cooper et al. [24] |
| ↓ | ↓ | ↓ | ↓ | Head: width ratio ↓ | 4822 men (16.5–72.3) |
Stone et al. [22] | |
| ↓ | ↑ | ↓ | 3729 men with normal sperm count (22–62) 498 men (21–66) |
Mukhopadhyay et al. [25] | |||
| Progressive motility ↓ | Elzanaty [26] | ||||||
| Youngest group (45–48): 2.8 ml Oldest group (56–80): 1.95 ml |
↓ | No significant change | ↓ 55 % ↓ in youngest group 50 % ↓ in oldest group |
↓ | 1174 men with no or mild erectile dysfunction (45–80) | Hellstrom et al. [23] | |
| 0.8 % ↓/year motility 0.9 % ↓/year progressive motility 0.4 % ↓/year rapid motility 0.2 % ↓/year linearity 0.2 % ↓/year straight line velocity 0.3 % ↓/year average path velocity |
97 healthy men (22–80) | Sloter et al. [27] | |||||
| 0.01 ml ↓/year | ↓ | 0.27 % ↓/year | %0.039 ↓/year | 889 fertile men (24–>45) | Pasqualotto et al. [28] | ||
| 0.03 ml ↓/year | 4.7 % ↓/year total progressivity motile sperm count | 0.7 % ↓ /year motility 3.1 %↓ /year progressive motility | 97 healthy men (20–80) | Eskenazi et al. [29] | |||
| 29 % ↓ Older group | No significant change | No significant change | 32 % ↓ progressive motility in older group | 40 % ↓ morphologically normal forms Tail defects 27 % ↑ in older group |
66 older men (≥50) and 134 young men (21–25), in both groups proven fertile and men in barren couples | Jung et al. [34] | |
| 2.6 × 106 ↓/year | 441 couples underwent IVF (male age 22–64) | Paulson et al. [30] | |||||
| ↓ | Total and motile sperm count ↓ | ↓ | 20,411 non-azoospermic infertile men (15–74) | Andolz et al. [31] | |||
| No significant change |
302 fertile men (20–45) | Bujan et al. [32] | |||||
| Microsephalic, macrosephalic, duplicate heads and coiled tails ↑ | 214 fertile men | Bujan et al. [33] |