Male Fertility Declines Rapidly After Age 40
A man’s age and semen characteristics affect the achievement of pregnancy in in vitro fertilization (IVF) treatments with donated oocytes, Brazilian researchers have found.
In their retrospective analysis, male age older than 41 years was found to reduce the odds of pregnancy, while enhanced sperm morphology criteria increased the chances of pregnancy. Their findings were reported atthe 2011 meeting of the American Society for Reproductive Medicine.
Led by Paula Fettback, nurse researcher at the Huntington Reproductive Center in São Paulo, Brazil, the team looked at outcomes from 570 IVF treatments with oocyte donors at their institution. The use of oocyte donors allowed them to isolate the influence of the male’s age on IVF success.
Donor eggs were from women 18 to 30 years of age with a body mass index of 28 kg/m2 or less. All oocyte donors and their recipients underwent physical, endocrine, transvaginal ultrasonography, and infectious disease evaluation.
There was no significant difference in the number of embryos transferred, the percentage of top quality embryos transferred, and the recipient’s age between the group that achieved pregnancy and the group that did not achieve pregnancy.
The mean age of the men whose partners achieved pregnancy was 41 years, while the mean age of those for whom IVF was unsuccessful was 45 years. Fertility declined by up to 7% with each additional year of age for the male partner – the chances of pregnancy declined from 60% at age 41 to 35% at age 45 years.
The percent of normal strict morphology according to Kruger’s criteria was also significantly higher in those achieving pregnancy versus those not achieving pregnancy (3.5% vs 2.2%). “Every 1% increase in Kruger’s strict morphology criteria increased the chances of pregnancy by 22%,” said Fettback.