Sperm counts and concentrations are falling globally and in Iowa, according to recent updates made to a 2017 study. 

The study suggests that the average sperm count globally has dropped from 104 million per milliliter to 49 million per milliliter in the past 50 years. The threshold below which low sperm counts affect reproduction is under 40 million per milliliter.

Since the numbers are still averaging around 50 million per milliliter, Amy Sparks, University of Iowa Hospitals and Clinics director of the andrology and vitro fertilization labs and clinical assistant professor, said it is hard to know if people should be concerned for the future and the cause of the declining counts. 

“While it’s not approaching the infertility levels, it does bring up some concern that men’s health has been impacted,” Sparks said. “We can talk about diet, about what our food and water have touched, environmental impacts, and hormone endocrine disruptors that are possibly in our environment, but until we do a serious look at what they’re being exposed to, and possibly what they were exposed to even back to in utero, it is hard to know.”

The Human Reproduction Update, published in the Oxford Journal, reported new data concerning sperm counts from 2011 to 2018. It also added data from South America, Asia, and Africa, which previously had incomplete data sets.

Sparks said studies like this require manual counts for accuracy. 

“There are computer-aided semen analysis systems out there, but the challenge with those systems is their level of detection,” she said. “They are not built for that low of a sperm concentration, so we don’t use it in our lab.”

Sparks said, it is hard to track average sperm counts because the people seeking treatment are often those who struggle with fertility at the UIHC labs. She said without additional funding, the UI clinics are not able to do more in-depth analysis.

Iowa has low sperm counts and fertility rates compared to other U.S. states, said Trenton Place, Mid-Iowa Fertility Clinic physician. 

In Iowa, 60.4 of 1,000 women ages 14 to 44 are fertile. In the neighboring state of Illinois, 53.8 of 1,000 women of the same age are fertile, according to the Centers for Disease Control and Prevention. 

Place said alcohol, marijuana, and nicotine consumption can play a role in sperm counts. But with modern technology, current global sperm rates should not be a concern.

“While it is concerning as a whole, it doesn’t mean that everybody needs to go out and freeze sperm,” Place said. “We have really great technology, like IVF, where we really only need one sperm or egg and even if there are only a million sperm, we have plenty of sperm to choose the best quality one to fertilize an egg with.”

However, this treatment is not financially accessible to everyone. At the Mid-Iowa Fertility Clinic, located at 1371 NW 121st St.,  Clive, Iowa, freezing and storing semen costs around $300 a year. Procedures like in vitro fertilization can cost over $10,000.

Place said while the trend in male sperm counts can give an interesting insight into male health and fertility, there should be more concern for female fertility rates. 

“Female fertility is a lot more sensitive to changes,” he said. “At least 70 percent of my practice is women who have issues with obesity and polycystic ovarian syndrome, so I am a lot more concerned on that front.”

According to the U.S. Census Bureau, female fertility rates have declined by around 43 percent in women ages 20 to 24 and around 67 percent in women ages 35 to 39 since 1990.

Claire Pavlik, UI department of geographical and sustainability sciences lecturer, said in the U.S. and other developed countries, the decline in fertility and sperm counts may not be a pressing issue because people are choosing to have fewer children.

“There are things like the legalization of the birth control pill and more equality in the workplace,” Pavlik said. “There’s also been a lengthening of the number of years of education, and that has contributed to people marrying later and choosing to have fewer children.”

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In the developing world, the number of infants and children living to adulthood is increasing, Pavlik said. Because of this, people in developing countries are not having as many children to make up for the ones who do not survive. 

Pavlik said the decline in sperm counts and fertility, however, may not be an entirely bad thing. On a global level, it could help manage overpopulation.

“I think one of the key things is, globally, birth rates have been falling, and for women, total fertility rates,” Pavlik said. “In many respects, that’s viewed as positive in terms of some of the environmental crises like climate change.”