Sperm do not swim, they spin

Sperm do not swim, they spin

Sperm obviously play a vital role in the fertilisation of almost every living organism on the planet. They have long tails called flagella that help to propel the little swimmers up through the reproductive tract to the egg, however recent research has shown that the way we originally thought the sperm swim, is in fact incorrect.

A single sperm needs to travel on average approximately 10cm to reach the egg, which is equivalent to a human walking from Sydney to Perth and back again. The scientist who discovered sperm did so after he developed his own microscope out of molten glass in the 17th century and described them as a “living animalcule” that had a “tail, which, when swimming, lashes with a snakelike movement, like eels in water”. To this day, scientists have believed sperm are propelled forward by whipping their tails back and forth, however what we believe we are witnessing is simply an optical illusion.

By using state-of-the-art 3D technology, researchers from the United Kingdom and Mexico were able to construct the tail of a sperm. The sperm’s tail or flagella is so fast, it is capable of beating over 20 swimming strokes in less than a second. Scientists needed a camera fast enough to capture this high-speed movement, and break it down frame by frame, and what they discovered was that the sperm’s tail in in fact skewed and will only wiggle on one side.

In order for the sperm to adapt and not simply swim around in circles, they roll as they swim, similar to the way otters will move in a corkscrew movement through the water. The way the sperm rolls gives off the optical illusion that its tail has a side-to-side movement, however this new development has revealed that in order to correct their lop-sidedness, the sperm will essentially “drill” their way through the fluid as they move towards the egg.

By understanding more about the structure of the sperm, scientists can use this information to help develop more advanced diagnostic tools for identifying unhealthy sperm and helping to improve fertility.

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FAQs about improving natural fertility

Will stress affect my ability to get pregnant?

Yes, chronic stress can impact fertility by disrupting hormonal balance and ovulation patterns. Managing stress through relaxation techniques, regular exercise, adequate sleep, and mindfulness practices may help optimise your chances of conception. Consider speaking with a counsellor if stress feels overwhelming.

How does my partner's health affect our fertility?

Sperm health accounts for about 40% of conception challenges. Your partner can improve sperm health by maintaining a healthy weight, avoiding excessive heat exposure (hot tubs, saunas, tight clothing), limiting alcohol, quitting smoking, managing stress, and taking a multivitamin with antioxidants. Sperm takes about 3 months to develop, so lifestyle changes need time to show results.

When during my cycle am I most fertile?

Your fertile window typically spans 5-6 days, ending on ovulation day. For a regular 28-day cycle, this usually falls between days 10-15, with peak fertility 1-2 days before ovulation. Track your cycle using ovulation predictor kits, basal body temperature, or cervical mucus changes to identify your unique pattern. Having intercourse every 1-2 days during this window optimises your chances.