Objective: To determine whether the presence of protamine 2 precursors (pre-P2/P2 ratio) and the protamine 1 to protamine 2 ratio (P1/P2) are related to the assisted reproduction outcome.
Design: Prospective study.
Setting: Assisted Reproduction Unit and University laboratory.
Patient(s): One hundred two infertile patients undergoing treatment at the Assisted Reproduction Unit of the Hospital Clinic of Barcelona.
Intervention(s): Intracytoplasmic sperm injection (ICSI) and/or IVF treatment of the infertile patients, sperm protamine analysis through electrophoresis and densitometry, and pre-P2 analysis through Western blot.
Main outcome measure(s): The presence of protamine 2 precursors (pre-P2/P2 ratio), sperm P1/P2 ratio, fertilization rates by IVF and/or ICSI, and pregnancy outcome.
Result(s): Pre-P2/P2 and P1/P2 ratios are positively associated with the pregnancy rate. In addition, the P1/P2 ratio is positively associated with the proportion of embryos obtained by IVF, but not by ICSI. The pre-P2/P2 ratio was not related to the fertilization rate.
Conclusion(s): Decreased pre-P2/P2 and P1/P2 ratios are related to a poor pregnancy outcome, but not with the proportion of embryos obtained after ISCI.