A Sperm's Journey
The way that the sperm finds its way to the fallopian tubes is a miracle by itself. This is when sperm motility comes into play. A good healthy sperm has what is called progressive motility. This is to say it swims in a fairly straight line and has the ability to get where it is supposed to go. Sperm with non-progressive motility tend to swim in circles, getting nowhere.
"Sperm have been shown to appear in the fallopian tubes as early as 10 minutes after deposition into the vagina," says Dr. Lipshultz. "A steady state of sperm is seen in the fallopian tubes after 45 minutes."
According to Dr. Lipshultz, the sperm and egg send molecular signals to each other that are referred to as "chemotactic" factors. "This is the same way that many cells in the body communicate with one another," says Dr. Lipshultz. "This signaling mechanism is complex, and researchers are not certain which are the exact messengers in this process."
Dr. Abe Halfen, an infertility specialist in Miami with South Florida Institute for Reproductive Medicine, says that once the sperm is ejaculated into the woman's vagina, it will pass through the cervix and enter the uterus aided by its tail movement. "It progresses forwardly and enters the fallopian tubes and, also aided by the cilia from the fallopian tubes, reaches the ampullar region of the tube," he says. "If ovulation was successful and the egg has entered the fimbriated portion of the tube, the sperm will penetrate it."
Dr. Halfen says that the sperm will survive for three to five days or perhaps longer in a woman's cervix in the presence of good mucus. The sperm left in the vagina are destroyed by acidity of vaginal secretions within hours.
The final step in the sperm's long journey is when it encounters the egg and fertilizes it. The sperm first has to penetrate the tough outer layer of the egg. Enzymes help the sperm get through this outer layer, and its whip-like tail motion helps the sperm with the final breakthrough. However, the tail of the sperm breaks off before the sperm head completely enters the egg.
"The best general guidelines for any couple wanting to conceive is that anything that is good for their general health is good for their sperm," says Dr. Lipshultz. "Conversely, anything harmful to their general health is bad for sperm. It is important to know that sperm represent some of the most sensitive cells in the body with respect to their ability to tolerate extreme conditions (heat, toxins, drugs, smoking, excessive alcohol). A healthy diet, replete with antioxidants with avoidance of situations which place the testicles in extreme heat (hot baths) is considered good general advice."
Basically, the healthier your partner is, the healthier his sperm will be. And good health will only leave you both better prepared to deal with the demands of a newborn once your baby arrives.