IVF & Treatment Basics
Sperm washing concentrates the best-swimming sperm and removes unwanted fluid. This guide explains the methods used in reproductive clinics, what happens during the process, and why it matters.
Everything that comes out in ejaculated semen is not useful. . A typical ejaculate contains sperm cells, seminal plasma (fluid produced by the prostate and seminal vesicles), white blood cells, bacteria, dead cells, and other debris. Sperm washing removes this seminal fluid and debris, leaving concentrated, motile sperm ready for fertilisation.
Seminal plasma contains compounds that:
Promote sperm survival in the vagina (irrelevant in IVF/IUI)
Can trigger immune reactions in the uterus (potentially reducing IUI success)
Contains bacteria and white blood cells that may reduce embryo quality if present during fertilisation
The presence of seminal fluid is less important in IVF since sperm are placed in culture media rather than directly with eggs. Sperm are inserted directly into the uterus during IUI, where seminal plasma may cause inflammation; elimination increases the likelihood of conception.
Different clinics use different methods:
Simple wash: centrifugation and resuspension in clean medium (basic, effective)
Swim-up: allowing sperm to swim into fresh medium, leaving debris behind (widely used, very effective)
Density gradient: layering semen and separating by density; concentrates the most motile sperm
All methods produce clean, concentrated sperm. The choice depends on clinic resources and semen parameters. Poor semen samples (very low count, poor motility) may need specialised techniques like swim-up or gradient centrifugation. These couples should also consider ICSI if the ongoing treatment does not work.
Normal semen: standard washing is fine; no special technique needed
Low count (<5 million/mL): may need density gradient to concentrate remaining sperm
Very poor motility: swim-up may be preferred to select the most active sperm
Very low count and poor motility - may benefit only from ICSI. Microfluidics may help in sperm selection.
Samples with high WBC (white blood cells): standard wash; antibiotics may be given beforehand
Here’s an example - A sample with 20 million sperm might yield 8 to 10 million motile sperms after washing. It may appear that the count has reduced, but what the post-wash count shows is the actually useful sperms. This is why semen analysis is done before IVF/IUI, to ensure adequate post-wash numbers.
Slightly different donor samples are frozen, so they're thawed first, then washed using the same techniques as fresh samples.
Freshly collected semen is washed immediately, typically within 1 hour of collection. If semen is frozen (previously frozen sample or donor sample), it's thawed, washed, and used within 1–2 hours. The goal is minimal delay from collection/thaw to fertilisation or insemination.
Q: Does washing reduce sperm count further?
A: Here’s an example - A sample with 20 million sperm might yield 8 to 10 million motile sperms after washing. It may appear that the count has reduced, but what the post-wash count shows is the actually useful sperms. This is why semen analysis is done before IVF/IUI, to ensure adequate post-wash numbers.
Q: Is sperm washing different for donor samples?
A: Slightly different—donor samples are frozen, so they're thawed first, then washed using the same techniques as fresh samples.
