Increased pregnancy after reduced male abstinence

Abstract

This study was conducted to test the hypothesis that continuous epididymal sperm depletion after recurrent ejaculations (REC) in contrast to a period of abstinence (ABS) results in a decreased level of sperm DNA fragmentation (SDF) and a consequent increased rate of pregnancy. Forty couples undergoing intra-cytoplasmic injection (ICSI) were asked to abstain from ejaculation for a period of 4 days and then ejaculate once per day for a period of 4 days, followed by a period of abstinence for 12 hours; sperm samples obtained after ABS and REC were assessed for volume, concentration, motility, and SDF and compared in 25 of the patients. Additionally, and in a different experiment, the pregnancy rate of this experimental group (40 couples) was compared to a control group of 150 couples in which the males had abstained from ejaculation for 4 days prior to ejaculation. Sperm selection was performed using density gradient centrifugation prior to ICSI. Semen quality in the REC group that was assessed over the course of the ejaculation schedule showed a decrease in semen volume (67%) and SDF (27%) following sperm selection; there was no difference for sperm motility or sperm concentration. When the pregnancy rate between the 40 couples in the REC group and 150 couples in the control ABS group were compared, the REC group had a pregnancy rate of 56.4% (25/40), whereas the ABS rate was only 43.3% (65/150) (p = 0.030). We conclude that recurrent ejaculation every 24 hours for four days with a final abstinence of 12 hours, combined with sperm selection using density gradient centrifugation, produces a significant increase in pregnancy rate when using ICSI. As ICSI was the strategy selected for fertilization, we propose that the observed reduction in SDF was the primary factor leading to improved reproductive outcome.

Keywords:

• assisted reproduction
• fertility
• male factor
• sperm DNA fragmentation

Acknowledgments

The authors thank Prof. Godfrey M. Hewitt and Steve Johnston for critical reading of the manuscript.

Declaration of interest: This work was partially supported by a grant (BFU2010-16738) from Ministerio de Ciencia y Tecnología, Spain (MCYT). The authors report no conflicts of interest.

Author contributions: Conceived and designed the experiments: PS-M, FS-M; Performed the experiments: PS-M, FS-M, MG-M; Analyzed the data: JG; Wrote the manuscript: JG, PS-M.