Male Fertility Worsens With Age
The older a man is, the harder it is for him to conceive with a partner, according to researchers who say a man's age should be considered as much as a woman's when it comes to fertility.
Men aged over 50 who took part in the study were "significantly" less likely to conceive or have a baby with their partner than those aged 40. The research published in the journal Human Reproduction also showed the likelihood that a man could have a baby with his partner dropped by 4.1 percent every year he aged, regardless of the woman's age. The chance of conceiving meanwhile fell by 3 percent each year, and the risk of miscarriage rose by 4.5 percent.
The study involved 1,506 couples struggling to conceive for an unknown reason, who had 2,425 cycles of treatments at the Monash IVF fertility clinic in Australia. The participants had undergone at least one round of IVF, where an egg is taken from a woman's ovaries and fertilized with sperm in a lab before being inserted into the womb, and intracytoplasmic sperm injection (ICSI), where the egg is injected individually with a sperm.
The men in the study were 46 years old on average, ranging from 27 to 77, and had normal sperm, while the women were between 21 and 48 years old and were 37 on average. In order to avoid skewing the results, women who had gynecological problems, including endometriosis, were excluded from the study, as were couples using frozen eggs and sperm, or who had genetic diseases.
In their paper, the researchers wrote: "The effect of male age on the outcomes of infertility treatments is controversial and poorly explored. In contrast, fertility is known to decline significantly with female age beyond the mid-30s, and reduced oocyte [egg] quality plays an important role."
As men age, they explained, it is thought that their sperm becomes more vulnerable to DNA damage.
The authors acknowledged the study was limited because it is difficult to uncover the cause of fertility problems, and the results might relate to a wider population due to the strict selection criteria.