Studies that have recently come out of Sweden have revealed that a woman’s eggs may play a crucial role in selecting sperm.
Researchers from Stockholm University analysed samples of sperm and follicular fluid and found that some of the samples of follicular fluid attracted more sperm than others.
Eggs release chemicals called chemoattractants, which are small soluble proteins that create an attraction between the egg and the sperm. The eggs will use these chemical signals to help guide the sperm which will increase the likelihood of fertilisation. The signal produced by the egg will encourage the selected sperm to swim faster and straighter to help them reach the correct place whereas it will also signal for the undesirable sperm to “slow down”.
This study has revealed that it is possible that eggs could be attracted more to sperm that are genetically compatible, which will increase the likelihood of fertilisation. This also shows that in couples who are having trouble conceiving naturally with no clear cause, it is possible that the chemical signalling between the egg and the sperm be the reason.
Although there is a need for future research in this area, this has given us some incredible insight into how the egg will potentially “choose” sperm and more importantly, this information could help advance fertility treatments worldwide, especially in cases where with many frustrated couples, their inability to conceive is simply “unexplained”.