Abstract: PD13-02
Sources of Funding: This investigation was supported by the University of Utah Study Design and Biostatistics Center, with funding in part from the National Center for Research Resources and the National Center for Advancing Translational Sciences, National Institutes of Health, through Grant 8UL1TR000105 (formerly UL1RR025764).

Introduction

Traditionally, most fertility clinics recommend 2-5 days of abstinence before semen collection. However, the impact of abstinence time on semen quality in subfertile patients is not known. We hypothesized that shorter abstinence times were associated with reduced sperm quality for subfertile couples. We used a large population of subfertile men to test this hypothesis. _x000D_

Methods

From 2002-2013, we retrospectively reviewed 19255 semen analyses from 15623 subfertile patients visited at our fertility clinic. For each encounter, data on patient age and semen parameters were extracted along with abstinence time. Abstinence time was categorized into 4 groups (≤2 days; >2 & ≤5 days; >5 & ≤7 days; >7 days). Sperm concentration, count, and total motile sperm count (TMSC) were log-transformed for analyses due to distribution skew and reported as ratios. Linear mixed effect regression models adjusted for age were used to test the effect of abstinence categories on semen parameters. Estimates and their 95% confidence intervals (CIs) were reported, and significance was assessed at the 0.05 level._x000D_

Results

A total of 11782 encounters (10095 patients) remained for the final analysis after exclusion of patients <18 years old, azoospermic samples, and those with missing values. Mean age was 32.4 (standard deviation: 6.5) and median abstinence time was 4.0 days. Table 1 summarizes encounter data stratified by abstinence days. On average a consecutive increase in abstinence category was associated with increases in: concentration (0.32 ml, 95% CI: 0.28, 0.37), ejaculate volume (12%, CI: 7, 17), total sperm count (23%, CI: 19, 29) and TMSC (20%, CI: 15, 26). However, an increase in abstinence time was associated with decreases in: sperm viability (-1.67%, CI: -2.14, -1.20), total motility (-1.81%, CI: -2.36, -1.26), progressive motile sperm (-1.35%, CI: -1.94, -0.76), and normal tail morphology (-1.05%, CI: -1.41, -0.68). All p-values were <0.001.

Conclusions

Although shorter abstinence time was associated with slightly better sperm viability, motility and morphology, changes in TMSC might be more clinically relevant for infertility purposes. Lengthening the abstinence period may increase the total count and TMSC, which could be beneficial for subfertile patients with lower TMSC at baseline.

Funding

This investigation was supported by the University of Utah Study Design and Biostatistics Center, with funding in part from the National Center for Research Resources and the National Center for Advancing Translational Sciences, National Institutes of Health, through Grant 8UL1TR000105 (formerly UL1RR025764).