Sperm Need Help

1995/02/01 Elhuyar Zientzia Iturria: Elhuyar aldizkaria

• Biologia

Sperm are swimmers, but to reach the fallopian tube they need a muscle push by contraction, as happens in surfing. According to Canadian researchers, the absence of such a push can be the cause of unexplained sterility in some women.

The waves are a consequence of the soft contractions of the muscle called miometrium of the uterus. According to Edward Lyons of the University of Manitoba, in women without fertilization problems the waves are concentrated in 80% of the time.

“Sperm are not salmon, so they can’t swim without help along the way,” Lyons explains. “They need help from the waves to reach the eggs.”

Lyons and Clifford Levi used ultrasound to measure contractions of 68 women who were treated for fertilization. The data obtained were compared with those obtained from the same number of women without fertilization problems. Because every minute only three waves are generated, the researchers recorded the ultrasonic measurements and saw them at fast speed. It was observed that the frequency of waves was very variable in non-pregnant women or that waves did not propagate in the right direction.

Lyons states that “abnormalities in the direction, frequency or intensity of contractions can be one of the most important causes of unexplained nonfertilization.” It says that the maximum frequency of waves is in the middle of the monthly cycle, that is, when the woman is ovulating and therefore has the greatest fertility. Contractions are stimulated by substances called postglandines that carry sperm.

For sperm it is very important to run, since the upper part of the vagina is very acidic, so only a few of the sperm manage to live. Therefore, the influence of waves is almost essential if you want sperm to reach the eggs.