When Egg & Sperm Don't Hook Up

It's pretty amazing what is still being learned about the most basic points along the conception trail. The big news recently is about a molecule that helps sperm cells bind to egg cells.

Researchers are calling it SLeX, short for sialyl-LewisX. Their study found SLeX on 70% of the 195 unfertilised eggs tested. If your egg cells don't have SLeX, sperm cells won't connect to it for the mating game. The best news: the authors of the study, who came from Britain, Taiwan, and the U.S., believe this discovery might lead to related infertility treatments in only about two years.

But what about in the meantime? While clinical diagnosis of this condition may be a couple of years away, the treatment for women with missing SLex is already available.

Intractytoplasmic sperm injection, or ICSI, is available for patients whose infertility is caused by lack of SLeX, as well as other causes. ICSI is one of assisted reproduction's most fascinating treatments -- a single sperm cell actually being injected into an egg cell. And while it may sound like science fiction, ICSI is no longer experimental. In fact, ICSI's been around for decades now and used with great success in conjunction with IVF. In 2008, staff of Houston Fertility Center had a related poster presentation accepted for that year's meeting of the American Society for Reproductive Medicine. Our study concluded that patients using ICSI had higher implantation rates.

One of the most incredible uses of ICSI is to treat even the most severe forms of male factor infertility. Since IVF with ICSI requires only one good sperm cell, the treatment has made biological dads out of men who previously had nearly no chance of having offspring.

Developments from our greater understanding of how SLeX can make or break conception attempts might lead to quicker, more direct diagnosis for couples with unexplained infertility. Every little detail makes a difference.

~Dr. Sonja Kristiansen, MD