Objective: To investigate paternal age effect mediated by biological modifications with use of data from assisted reproductive technologies.
Design: National IVF registry.
Setting: Fifty nine French IVF centers.
Patient(s): A total of 1,938 men whose partners were totally sterile, with bilateral tubal obstruction or absence of both tubes (to avoid bias sampling in analysis of paternal age) and treated by conventional IVF.
Intervention(s): None.
Main outcome measure(s): Risk of failure to conceive defined as absence of intrauterine pregnancy.
Result(s): The odds ratio of failure to conceive for paternal age > or =40 years was 2.00 (95% confidence interval [CI]: 1.10-3.61) when the woman was 35-37 years old, 2.03 (95% CI: 1.12-3.68) for age 38-40 years, and 5.74 (95% CI: 2.16, 15.23) for age 41 years and over.
Conclusion(s): As an increasing number of couples choose to postpone childbearing, they should be informed that paternal age over 40 years is an important risk factor for failure to conceive.