Nordic Sperm DNA Study

Introduction

The goal of this prospective observational study with an embedded randomized controlled trial (RCT) is to investigate the prevalence and clinical significance of sperm DNA fragmentation (damage to the genetic material in sperm cells) (SDF) among men undergoing fertility treatment and to determine whether an individualized lifestyle programme can reduce SDF and improve pregnancy outcomes. The study includes approximately 800 men undergoing fertility treatment at a Danish fertility clinic.

Objectives and methods

The main research questions are:

1. How common is elevated SDF among Danish men undergoing fertility treatment? 2. Is elevated SDF associated with reduced live birth rates and increased early pregnancy loss? 3. Can a 3-month individualized lifestyle intervention reduce SDF in men with high SDF levels (above 20%)?

The whole cohort will participate in the observational study. Participants with SDF above 20% will be invited to take part in the randomized controlled trial. In the RCT researchers will compare men randomized to an individualized lifestyle intervention with men receiving standard fertility care to determine whether the intervention reduces sperm DNA fragmentation and improves subsequent pregnancy outcomes.

All participants will:

* Provide semen samples for sperm DNA fragmentation testing and routine semen analysis. * Provide blood samples to measure hormones and other health markers

On the basis of SDF results participants will either:

* Have SDF of 20% or lower: Continue with routine fertility treatment and follow up. * Have SDF above 20%: Be randomly assigned to either a personalised 3-month lifestyle programme or standard fertility care. Participants in the lifestyle programme will receive personalised advice on diet, physical activity, smoking, alcohol, sleep, stress management and antioxidant supplements.

Ethics and dissemination

The study has been approved by the Regional Committee on health research ethics and complies with the General Data Protection Regulation. Written informed consent will be obtained from all participants before enrolment. Study findings will be disseminated through peer-reviewed scientific journals, conference presentations, trial registry reporting, and communication with participants and relevant stakeholders.