**Background:** Male factor infertility affects over 50% of infertile couples. Ejaculatory abstinence (EA) time is known to cause intraindividual variation in semen quality, and longer EA may expose spermatozoa to reactive oxygen species (ROS) in the epididymal tract, increasing DNA damage. The WHO manual (6th edition) recommends 2–7 days of EA for diagnostic purposes, while ESHRE recommends 3–4 days. This systematic review aimed to compare short vs. long EA and investigate associations with pregnancy rate, live birth rate, and DNA fragmentation index (DFI).
**Methods:** The review was conducted per PRISMA guidelines and registered in PROSPERO (CRD42022379039). A research librarian searched PubMed, Embase, and Cochrane in April 2022. Inclusion criteria: men of reproductive age; short EA as intervention; long EA as comparison; outcomes including pregnancy rate, live birth rate, and/or DFI. All original human studies were included; expert opinions, case studies, and protocols were excluded. Two investigators independently screened studies using Covidence.org. Risk of bias was assessed using the Scottish Intercollegiate Guidelines Network (SIGN) methodology checklist for cohort studies.
**Key Results:** Of 1235 identified studies, 24 met inclusion criteria (total 14,173 cases). Studies were conducted in Asia, North and South America, and Europe. EA ranged from less than 1 hour to 15–20 days. According to SIGN, 3 studies were high quality, 17 acceptable, and 4 low quality.
*Pregnancy Rate:* 13 studies examined pregnancy rate. Nine found significantly higher pregnancy rates with short EA vs. long EA. Four reported non-significantly higher rates with short EA. For example, Gupta et al. (n=1691 cycles) found significantly higher pregnancy rates with 1 day of EA (30.0%) vs. 2–5 days (25.4%), 6–7 days (15.0%), and ≥8 days (18.1%) (p=0.009). Borges et al. (n=818) found 40.0% pregnancy rate with ≤4 days vs. 10.0% with ≥4 days (p=0.016).
*Live Birth Rate:* All three studies reporting live birth rate found significantly higher rates with short EA. Shen et al. reported 65.2% live birth with 1–3 h EA vs. 47.7% with 3–7 days in frozen-thawed cycles (p=0.006). Barbagallo et al. found 22.0% with 1 h vs. 18.0% with 2–7 days (p=0.040). Periyasamy et al. found 36.1% with 2–4 days vs. 24.1% with >7 days (p=0.005).
*DNA Fragmentation Index:* 15 studies reported DFI. Eleven found significantly lower DFI with short EA. Four reported non-significant lower DFI (three of these had n<20). EA of 1 day or less was associated with the lowest DFI rates. Dahan et al. reported DFI 23.7% at 3 h vs. 34.6% at 3 days (p≤0.0001). Comar et al. (n=2458) found DFI 14.5% at <2 days vs. 17.1% at >5 days (p=0.001).
**Clinical Implications:** Short EA appears to be a safe, low-cost, non-invasive intervention that may improve ART outcomes. The evidence consistently favors short EA across different ART types (IUI, IVF, ICSI) and populations. The authors suggest that the WHO-recommended 2–7 days of EA may warrant revision, though the ideal timeframe likely varies by treatment type. Limitations include heterogeneous EA intervals across studies (precluding meta-analysis), varying DFI assay methods, and only 3 studies rated as high quality. The authors recommend future prospective RCTs with standardized EA intervals and within-subject controls for DFI studies.