Saturday, August 12, 2017 1:00 am
Sperm count falls sharply
Ariana Eunjung Cha | Washington Post
The quality of sperm from men in North America, Europe and Australia has declined dramatically over the past 40 years with a 52.4 percent drop in sperm concentration, according to a new study.
The research – the largest and most comprehensive look at the topic, involving data from 185 studies and 42,000 men around the world between 1973 and 2011 – appears to confirm fears that male reproductive health may be declining.
The state of male fertility has been one of the most hotly debated subjects in medical science in recent years. While a number of previous studies found that sperm counts and quality have been declining, some have dismissed or criticized the studies.
Shanna H. Swan, one of the authors of the new study published July 25 in the Human Reproduction Update, said she hoped this broad meta-analysis of all the published literature out there would put some of the uncertainty to rest.
“It shows the decline is strong and that the decline is continuing,” Swan said in an interview.
The analysis found drops only for men in Europe, North America and Australia and not for those in South America, Asia and Africa. Swan explained that this could mean that there's something specific to certain cultures or countries that affects sperm, but that it's also possible that there just isn't enough data yet to draw firm conclusions about the rest of the world. There have been far fewer sperm studies conducted in non-Western countries.
The most important data points in the study involved sperm concentrations for what are known as “unselected” men who haven't yet proven they are fertile. These are men in the studies who are on the younger side and are not yet fathers or do not have partners who are pregnant. Researchers estimated that these men had an average sperm concentration of 99 million per milliliter in 1973 but that that had dropped to an average 47 million per milliliter in 2011.
That is a disturbing number given that, according to World Health Organization criteria, men with a sperm concentration of less than 40 million are considered to have an impaired chance of conceiving and those with a sperm concentration of less than 15 million per milliliter are considered infertile.