Oligospermia / Asthenospermia / Teratospermia

OAT syndrome is the combination of low sperm count, poor sperm motility, and abnormal sperm shape in the same man. OAT is the abbreviation for oligoasthenoteratospermia. Each component has its own term: low count is oligospermia, poor motility is asthenospermia, and abnormal shape is teratospermia. A semen analysis measures all three. The results are compared against the lower reference limits in the WHO 2021 semen manual (6th edition). Those limits come from men who fathered a child, so they serve as guides. One low value on its own is not a diagnosis. The limits are a count below 16 million per milliliter, forward motility below 30%, and normal shape below 4%.¹ When all three values fall below the limit together, the pattern fits OAT syndrome.

OAT syndrome is a sign of a cause that has not yet been identified. Low values indicate that some factor is impairing sperm production. Common causes include varicocele, oxidative stress, low hormone levels, infection in the genital tract, and genetic factors. Identifying the cause shows whether sperm health can be restored. When no one searches for the cause, treatable problems remain hidden, and couples receive no real path forward.

A restorative approach to male factor infertility treats these results as a reason to evaluate both partners and search for the cause. ICSI bypasses poor sperm quality and leaves that cause in place. Treatment of the cause can improve sperm quality enough for natural conception. and restorative andrology.