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Male Obesity and More Play a Role in Conception
a blog by Claire, August 24, 2012
When couples are trying to conceive, women's weight, stress levels and age are often the focus. But now several studies are shining the spotlight on men and how their age and health affects their fertility.
"There is a growing body of literature which speaks to the overall health of the male partner in subfertile couples and outcomes," says Mark Leondires, a fertility doctor and medical director of Reproductive Medicine Associates of Connecticut. "Specifically, there are two recent publications in Human Reproduction, August 2012, and Fertility and Sterility, August 2012, which speak to a negative effect on sperm quality and embryo quality. Pregnancy rates in obese men with the use of ICSI did not overcome this effect. The authors reported an 85 percent decrease in the odds of live birth in men with abnormal BMI as compared to normal BMI.
"Clearly, more work needs to be done in this area, but there is a strong suggestion of a negative correlation between obesity and pregnancy," he continues. "This is both a call to arms for male partners to take better care of themselves and for the fertility community to educate male partners better."
To follow are some of the studies that were reported on in the last few weeks.
Male Obesity is Bad for Sperm
Australian scientists at the University of Melbourne Department of Zoology have discovered that a man's obesity negatively affects his sperm and leads to:
- smaller fetuses
- poor pregnancy success
- reduced placental development
The scientists generated embryos from both normal weight and obese male mice. The obese mice had been fed the equivalent of a western fast food diet for 10 weeks. The found that the rate of embryo implantation into the womb and fetal development decreased in these animals by up to 15 percent. Also, the placental weight and development was significantly less for embryos created from the sperm of obese males.
As of 2010, 35.5 percent of men in the United States were considered obese. Many doctors advise women to lose weight and get fit before trying to conceive. The Australian researchers advise that men do the same. The study is being presented at the Annual Scientific Meeting of the Endocrine Society of Australia and the Society for Reproductive Biology 2012.
Male Mice Pass on Anxiety to Their Daughters
Another mouse study conducted at the Tufts University School of Medicine in Boston and published in Biological Psychiatry has found that anxious fathers may pass along psychological disorders to their daughters. The researchers say that when young men are exposed to unstable lifestyles, their sperm cells change, which increases the risk of anxiety as they get older and increases the risk of psychiatric disorders in their daughters.
How did they figure this out? They exposed adolescent mice to chronic social instability (where the cage composition of mice was constantly changing). Then they analyzed the behavior of the offspring of the mice that had been stressed. They found that the female offspring demonstrated anxious and stressed behavior, as well as abnormal social communication. The male offspring, who did not exhibit the these behaviors, reproduced with non-stressed females, and guess what? Their female offspring inherited the anxiety as well!
The researchers are now looking for biochemical changes in the sperm of stressed fathers that could cause the inheritance of anxiety disorders, and they hope their work will cause other scientists to investigate whether there is the same effect on humans.
Age of Father Matters for Gene Mutations
The big news this past week was that the age of the father when a baby is conceived matters with regard to passing on gene mutations for such conditions as autism and schizophrenia. Read the story: Older Age of Father Linked to Autism, Schizophrenia in Children.