Progressive motility measures the percentage of sperm that swim forward in a straight line or large circles (grades A and B motility). It is distinct from total motility, which includes sperm moving in any direction including in place. Progressive motility directly reflects the sperm's ability to navigate the female reproductive tract and reach the egg for fertilisation.
The WHO 2021 lower reference limit for progressive motility is 30% (5th percentile of fertile men). Low progressive motility (asthenozoospermia) is associated with reduced natural conception rates and lower success rates in IUI (intrauterine insemination). Progressive motility is considered the most functionally relevant motility measure for natural fertility.
FAQs
What is the difference between progressive and total motility?
Total motility includes all moving sperm (forward, sideways, circular). Progressive motility only counts sperm swimming forward purposefully. Progressive motility is more functionally relevant as only forward-swimming sperm can navigate to the egg.
What is asthenozoospermia?
Asthenozoospermia is the medical term for below-normal sperm motility (progressive motility below 30%). It is one of the most common semen analysis findings in men with fertility problems.
Can motility improve with supplements?
Yes. CoQ10 (200-600 mg/day) and L-carnitine (2-3 g/day) have the strongest evidence for improving sperm motility. Improvements take at least 3 months to appear in semen analysis results.
Does abstinence period affect motility?
Yes. Very short abstinence (below 2 days) reduces sperm concentration. Very long abstinence (above 7 days) causes sperm ageing and reduced motility. The recommended abstinence period for standardised semen analysis is 2-7 days.
