Can women’s bodies “filter out” unwanted sperm?

Can women’s bodies “filter out” unwanted sperm?

Research has previously shown that it isn’t simply a matter of the strongest sperm making it to the “finishing line” that ultimately results in a healthy baby. However it’s a lot more complicated than most people believe.

When you factor in sperm quality, egg quality, embryo quality, age, endometrial receptiveness, multiple signalling pathways and hormone responses to name a few, the process becomes a very daunting experience for patients embarking on their own fertility journey. As scientists, we dedicate our lives and our careers to research that will help patients achieve their dream of starting a family.

New research has helped us learn that various chemicals that occur naturally in the female reproductive tract may actually improve or impair the sperm’s chance for reaching the egg.

Scientists from the University of Eastern Finland have discovered that the female reproductive tract has the ability to mediate a “post-mating sexual selection” towards some sperm.

The scientists studied the cervical mucous of females and found that there was a stronger effect on sperm from some males, and that the sperm that was more dissimilar genetically from the egg had an increased chance of fertilisation. Dr Jukka Kekäläinen, an Associate Professor in the Department of Environmental and Biological Sciences found that the results indicated that there is an immunogenetic capability when it comes to reproductive partners, the combination of both sperm and egg may be a highly selective process.0

“It is likely that gamete-level incompatibility can reduce the chance of conception but may not often completely prevent it,” Kekäläinen said. “Furthermore, gamete-level compatibility does not mean that partners are otherwise incompatible, with respect to their personalities.”

What does this mean for patients undergoing fertility?

This new research will help to improve our current understanding we have of undiagnosed infertility in many couples. Approximately 30% of patients experiencing infertility will struggle to find a diagnosis, which can be frustrating and discouraging. By improving our understanding of this area of infertility, it may help researchers and clinics to develop more personalised and accurate diagnoses.

Share

Fertility Testing News & Information

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.