Oligospermia
Oligospermia (also oligozoospermia) is a suboptimal concentration of spermatozoa in the ejaculate. The diagnostic threshold has moved across three World Health Organization reference eras. Historically, oligospermia was defined as fewer than 20 million sperm per milliliter, the WHO's 1999 threshold. The WHO's 2010 fifth edition lowered the limit to fewer than 15 million per milliliter. The WHO's 2021 sixth edition raised the limit again, to fewer than 16 million per milliliter. That is the threshold in current use. Each of these limits reflects the fifth centile among men whose partners conceived naturally within 12 months. That is a more precise reference population than the general "fertile men" label sometimes used to describe it. Oligospermia is among the most common findings in male-factor infertility. It frequently coexists with reduced motility (asthenospermia) and abnormal morphology (teratospermia); the combined finding is oligoasthenoteratospermia (OAT).
Underlying causes include varicocele, hypogonadotropic and hypergonadotropic hypogonadism, cryptorchidism, infection, environmental toxin exposure, heat exposure, oxidative stress, and idiopathic factors. Restorative Reproductive Medicine treats oligospermia by identifying and correcting its root cause rather than bypassing it. NaProTechnology evaluates both partners and directs treatment at the specific cause identified, whether structural, endocrine, environmental, or oxidative. This treats the male partner's fertility as a diagnostic question in its own right, rather than something to route around with assisted reproduction.
This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.