The aim of this study is to assess the evaluate the effectiveness of vitrified donor semen in intrauterine insemination treatments.

Sperm cryopreservation is an efficient procedure widely used in fertility clinics, that provides logistical flexibility and increases the potential for success in assisted reproduction. It has been demonstrated that reproductive rates are comparable when using frozen sperm or fresh semen. However, sperm freezing using standard protocols is inevitably associated with a loss of motility, membrane integrity, and other post-thaw sperm quality parameters due to what is known as cryodamage, which involves the formation of intracellular ice crystals, osmotic shock, and dehydration.

Sperm vitrification has been recently developed as an improved alternative, where freezing occurs extremely rapidly (-20,000 ºC/min). Consequently, the formation of intracellular ice crystals is reduced, leading to improvements in sperm motility, vitality, and integrity.

However, the use of vitrified semen in fertility clinics is scarce, and no study has addressed whether vitrification could affect reproductive outcomes, such as live birth.

The aim of this study is to assess the evaluate the effectiveness of vitrified donor semen in intrauterine insemination treatments through the analysis of clinical pregnancy (primary objective) and as secondary objectives the number of progressive sperm post-thaw, percentage of progressive sperm and biochemical pregnancy.

Inclusion Criteria:

• Patients undergoing Artificial Insemination with sperm from donor.
• Female partner's age < 35 years
• First IUI attempt
• Caucasian phenotype

Exclusion Criteria:

• Any adverse medical condition that may significantly affect reproductive outcomes

ART couples where the female partner is under 35 years old who are undergoing their first attempt of intrauterine artificial insemination with donor semen