Shorter ejaculation abstinence times linked to better reproductive outcomes during fertility treatments

In a recent systematic review published in the Journal of Clinical Medicine, researchers evaluate the association between ejaculatory abstinence time, rates of pregnancies and live births, and deoxyribonucleic acid (DNA) fragmentation.

Study:  The Influence of Male Ejaculatory Abstinence Time on Pregnancy Rate, Live Birth Rate, and DNA Fragmentation: A Systematic Review. Image Credit: IU liquid and water photo / Shutterstock.com

Background

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Male infertility, which can be diagnosed through semen analysis, contributes to over half of infertility cases among couples. Overall health and other factors such as age, body mass index (BMI), medications, metabolic syndrome, lifestyle, and behaviors such as alcohol intake, smoking, diet, and caffeine consumption, can affect semen quality. Semen quality can also vary within an individual based on the ejaculatory abstinence time.

In the epididymal tract, spermatozoa undergo physiological and biochemical changes that allow for their maturation in preparation for fertilization. However, spermatozoa are also exposed to reactive oxygen species (ROS) that cause DNA fragmentation, which has been linked to lower rates of pregnancy and live birth.

Comparisons with testicular sperm have revealed that storage and transition through the epididymal duct increase the risk of DNA fragmentation. Furthermore, previous studies have reported that shorter ejaculation abstinence times are linked to better sperm health. However, the association between ejaculation abstinence times and improved reproductive outcomes such as pregnancy and live birth rates remains unclear.

About the study

In the present study, researchers reviewed studies including men of reproductive age and evaluated short and long ejaculation abstinence times as the intervention and comparison, respectively. The investigated outcomes of these studies included the rates of pregnancy and live birth and DNA fragmentation.

Studies that were in English, Spanish, or any Scandinavian language were included. Data such as demographic factors, year of publication, country of origin of the study, population size, study design, abstinence times, cause of infertility, and observed outcomes were extracted from the studies for analysis. Additional data on the rates of pregnancy and live birth, type of assisted reproductive technology used for fertility treatments, and assay methods used to analyze DNA fragmentation were also included in the analyses.

The risk of bias was assessed for factors such as study selection, confounding, assessment, and statistical analyses using the Scottish Intercollegiate Guidelines Network. A quantitative analysis was conducted to determine the number of studies that reported pregnancy or live birth rates or DNA fragmentation results in association with ejaculation abstinence times.

Results

A shorter ejaculation abstinence time was found to improve pregnancy and live birth rates after the use of assisted reproductive technology. Semen analysis studies indicated that DNA fragmentation was also lower in semen collected after short ejaculation abstinence times as compared to semen samples collected after longer abstinence times.

The risk of bias analysis indicated that there were only three high-quality studies, none of which reported live birth rates as one of the outcomes. Furthermore, the small sample sizes in some of the studies increased the probability of Type II errors.

While many of the studies investigated the effect of shorter ejaculation abstinence times, the large heterogeneity in the investigated abstinence times made it difficult to form conclusions about the ideal ejaculation abstinence time. However, overall benefits in reproductive outcomes were observed when ejaculatory intervals were as low as one to three hours.

In couples undergoing assisted reproductive technology treatments, an increased number of spermatozoa with DNA fragmentation were linked to poor pregnancy outcomes. Furthermore, DNA fragmentation index was strongly correlated to ejaculation abstinence times, with the lowest DNA fragmentation index associated with an ejaculation abstinence time of less than one day.

Nevertheless, the authors caution that recommendations regarding ejaculation abstinence times should be made after carefully considering the fertility treatment type in use. To this end, ejaculation abstinence times may differ for fertilization based on intercourse, intrauterine insemination, in vitro fertilization, or intracytoplasmic sperm injection.

Conclusions

Overall, the review findings suggest that shorter ejaculation abstinence periods improved the rates of pregnancy and live births, while also reducing the likelihood of DNA fragmentation in spermatozoa.

Importantly, the studies included in the current review were heterogenous in abstinence time results, thus making it difficult to form conclusions about an ideal ejaculation abstinence time. While abstinence times of less than one day have been seen to improve reproductive outcomes, medical recommendations must be made after careful consideration of the fertility treatments in use.

Written by

Dr. Chinta Sidharthan

Chinta Sidharthan is a writer based in Bangalore, India. Her academic background is in evolutionary biology and genetics, and she has extensive experience in scientific research, teaching, science writing, and herpetology. Chinta holds a Ph.D. in evolutionary biology from the Indian Institute of Science and is passionate about science education, writing, animals, wildlife, and conservation. For her doctoral research, she explored the origins and diversification of blindsnakes in India, as a part of which she did extensive fieldwork in the jungles of southern India. She has received the Canadian Governor General’s bronze medal and Bangalore University gold medal for academic excellence and published her research in high-impact journals.