There’s an Obstacle Course for My Sperm?
Talk about competition, the sperm that actually fertilizes the egg has to beat over 249 million others to win the prize!
On average 250 million sperm are released each time a man ejaculates. When the starter’s pistol goes off, sperm begin a frenzied journey through the vagina, the cervical mucus and uterus in order to reach the egg waiting in the fallopian tube.
Along the way, sperm go in the wrong direction, run out of energy or are eaten by white blood cells guarding the egg.
Ultimately, only a few hundred sperm reach the egg. Among these finalists is the champion! This is natural sperm selection.
Although it sounds like a random and frenzied dash to the finish line, Nature has a plan – the vagina and uterus have grooves that direct the healthiest sperm toward the egg.
The most robust sperm navigate the course best and reach the egg first, which is Nature’s way of ensuring the healthiest DNA is passed from father to child.
In assisted reproductive technologies, however, semen is prepared for fertility treatments by spinning it in a high-speed centrifuge for 20 minutes – the equivalent of being spun over 30,000 times with forces up to 500 times the Earth’s gravity.
Such traumatic preparatory steps can cause the delicate DNA in the head of the sperm to break apart (fragmentation) affecting that sperm’s ability to fertilize the egg.
After the centrifugation, the pellet at the bottom of the centrifuge tube is then covered with fluid to let the “best” sperm swim to the top of the tube where they can be retrieved for use in intrauterine insemination (IUI) or IVF. While this has been the historical method to prepare sperm, no one really knows if the sperm selected for IUI or IVF is the healthiest sperm or the one that Nature would have chosen.
All this is changing thanks to a new device that mimics natural sperm selection. Developed at Harvard University, the Natural Sperm Selection microchip mimics the natural grooves and anatomy of the female reproductive tract.
As in nature, only the healthiest and most robust sperm can transverse the length of the obstacle course on this chip.
Initial studies have revealed that the sperm selected by the microchip have a near-zero rate of DNA fragmentation. Preliminary clinical data have demonstrated increased pregnancy rates following use of sperm prepared using the microchip versus older clinical methods like centrifugation.