RMANJ Fellow Wins Award for Research into Declining Total Motile Sperm Count
Reproductive Medicine Associates of New Jersey (RMANJ) second year fellow Dr. Ashley Tiegs received the Traveling Scholar Award from the Society for Male Reproduction and Urology, typically awarded to training urologists, at this year’s annual American Society of Reproductive Medicine (ASRM) meeting for research that found declining total motile sperm count in men presenting for fertility treatment.
Research: Total Motile Sperm Count
Dr. Tiegs, who conducted the retrospective study with RMANJ’s Dr. Jim Hotaling and several other investigators, looked at the total motile sperm count (TMSC) of 119,972 men presenting for testing at either RMANJ or IVI clinics, located in New Jersey and Spain, between 2002 and 2017. The study was the largest evaluation of semen analyses to date, and aimed to shed more light on declining sperm counts worldwide. Studying sperm counts is vital because male factor infertility accounts for about half of all infertility cases.
Although there are two other ways to measure sperm health – total sperm count and sperm morphology – the most important parameter which predicts likelihood of achieving pregnancy is TMSC.
By studying TMSC in men presenting for fertility treatment, something that had never been done before, Dr. Tiegs could determine if declining sperm counts were clinically relevant. In other words, did the decline drop below a threshold at which treatment is potentially required?
The research showed it did.
Results: Total Motile Sperm Count
Dr. Tiegs separated the data into three groups: men with TMSC greater than 15 million sperm, numbers which would not necessitate fertility treatment in and of itself; men with TMSC between five and 15 million, who would be at risk of requiring a minor fertility treatment such as intrauterine insemination (IUI); and men with TMSC between zero and five million, who would be at risk of requiring in vitro fertilization (IVF), possibly with intracytoplasmic sperm injection (ICSI), to achieve a pregnancy.
Because the study consisted of one sample for each man and participants were not retested over time, Dr. Tiegs and colleagues used a regression analysis to study changes in membership within these treatment-associated TMSC groups over time. Her research found that there was a shift in the proportion of men within these groups over time: the percentage of patients in the group with normal TMSC declined over time (i.e., patients requiring no insemination treatment, barring other female factors), while the proportion of men in the group with severely low TMSC (and therefore, at high risk of requiring insemination treatment) increased over time.
Specifically, Dr. Tiegs found that the proportion of men with normal TMSC declined by nine percent (87.6 to 78.7%) over the course of the study (2002-2017). Conversely, the proportion of men at risk of requiring fertility treatment grew over time: the percentage of men with abnormal total motile sperm count presenting for treatment grew from 12.4% in 2004 to 21.3% in 2017.
With such findings indicating that men are increasingly at risk of requiring fertility treatment over the past one and a half decades, we have to wonder: why?
Decreasing TMSC over time due to an increasing age of male patients presenting for care over the years was ruled out, as the average age of men presenting to the clinics remained the same throughout the study period. Although the study did evaluate causes of the declining total motile sperm count trend, Dr. Tiegs says that perhaps the TMSC differences seen in this study were simply due to differing referral patterns over time. Alternatively, much research exists regarding the adverse effects of toxic lifestyle and environmental influences on sperm quality, but how big a role each contributing factor plays is not completely understood. Environmental factors that have been investigated include endocrine disrupting chemicals, such as plasticizers like bisphenol and phthalates, polychlorinated biphenyls (PCBs), which are used to make electrical equipment, and pesticides. As the etiology of this declining TMSC trend remains only speculation, continued investigations into factors that may adversely affect sperm quality are warranted.