November 5, 2010 (Denver, Colorado) — Exposure to laptop computers might adversely affect male fertility by inducing DNA fragmentation and decreasing progressive motility, according to research presented here at the American Society for Reproductive Medicine 66th Annual Meeting.
In the first study of its kind to evaluate the effect of laptop computers receiving wireless Internet signals on human spermatozoa, researchers evaluated semen samples from 15 men. The samples were separated into 2 incubation groups: one that was exposed to a laptop computer receiving a WiFi signal for 4 hours, and another that was not.
Despite the fact that the 2 groups were kept at a controlled temperature (25 °C) to rule out thermal effects, the results showed significant DNA damage and decreased sperm motility in the laptop-exposed group.
"We controlled and fixed the temperature to avoid thermal effects," said Conrado Avendano, PhD, lead author of the study and director of research at the Nascentis Reproductive Medical Center in Cordoba, Argentina.
Prior to incubation, the sperm was assessed for parameters such as concentration, motility, morphology, and vitality. Evaluation after incubation showed decreased sperm motility in the laptop-exposed group (73.5 ± 8.2 vs 63.6 ± 7.3; P < .05), increased sperm immotility (18.8 ± 6.9 vs 28.3 ± 7.3; P < .05), and an increase in sperm DNA fragmentation (6.3 ± 8.1 vs 13.1 ± 9.2; P < .05), compared with the nonexposed group.
"After 4 hours of incubation, the sperm motility had decreased significantly in the exposed group, compared with the unexposed group," Dr. Avendano told Medscape Medical News.
"In addition, we evaluated sperm DNA fragmentation and saw that after incubation under the laptop, the percentage of spermatozoa with DNA damage was increased more than in the unexposed group," he said.
No significant differences were seen in levels of nonprogressive sperm motility and vitality.
The findings regarding sperm motility and DNA fragmentation raise concerns about the effect of laptops on male fertility, Dr. Avendano said.
"It has been shown that sperm motility and DNA fragmentation quality are necessary for normal fertilization," he said. "Therefore, we speculate that the use of [WiFi-connected] portable computers . . . near the testis may decrease sperm quality by a nonthermal effect, and likewise may reduce the chance of pregnancy."
Previous studies looking at the effects of cell phones have shown that the devices can reduce semen quality, and laptop studies have looked at the thermal effects of laptop computers; however, this is the first study to show the effect of exposure to a laptop computer and to radio frequency electromagnetic waves from its WiFi signal on sperm quality in an in vitro model, Dr. Avendano said.
"Previous work by another research group has shown that the use of laptop computers on the lap may increase scrotal temperature. This point is very important, because it has been shown that increased temperature is detrimental to normal sperm generation (spermatogenesis)," he explained.
To the best of our knowledge, this is the first study to evaluate the impact of laptops on human spermatozoa and to demonstrate a detrimental effect from a nonthermal mechanism, he continued.
The study's limitations include its small size and the fact that it was an in vitro study. Dr. Avendano said that future research will probe the possible mechanisms behind the effect.
"We want to know the molecular mechanism that produces the detrimental effect on the sperm," he said. "We believe that if we know the mechanism, we may know how to counteract adverse effects. [Therefore], we want to do a similar evaluation in an in vivo group."
In the meantime, he said, the preliminary findings represent a red flag in regard to laptop use.
"This is the beginning of a new line of research," and new data will be needed to confirm this finding, Dr. Avendano said. "However, we recommend that our patients do not use the computer on the lap, especially if they are of reproductive age."
Keith Jarvi, MD, professor in the Department of Surgery at the University of Toronto, Ontario, agreed that much more research will be necessary before any conclusions can be drawn, but the study nevertheless sheds light on a potentially important issue.
"This is a very interesting but very preliminary study. The effect of laptops on real people's testis is still unknown, and this study does not shed light on this," he said.
"However, the study does provide hints as to what might be happening, and [points us toward] the kinds of studies in humans that would answer the question about the effect of laptops on male fertility," Dr. Jarvi said.
Dr. Avendano and Dr. Jarvi have disclosed no relevant financial relationships.
American Society for Reproductive Medicine (ASRM) 66th Annual Meeting: Abstract O-249. Presented October 27, 2010.