Infertility is a heartbreaking experience that carries a huge emotional toll, and the reasons for it remain elusive or unknown. Some of the factors that influence your fertility might have occurred before you were even born.
A Danish study, led by Linn Arendt of Aarhus University, has revealed that if a mother’s pre-pregnancy weight falls in the overweight range, it can increase the chances of infertility for future sons – but has no affect on future daughters trying to conceive.
Key research points
- A mother’s pre-pregnancy weight can affect the future fertility of her sons
- Adult sons of overweight or obese mothers had a 1.4 times greater risk of infertility
- There was no correlation between a mother’s pre-pregnancy weight and the fertility of her adult daughters
Infertility affects about 12% of couples, they report. One third of cases are due to male reproductive issues, another third is due to female reproductive issues, and the final third is due to a combination of male and female, or to unknown, factors.
The study highlights how the causes of infertility are diverse and long-reaching, and can also be a specific problem for one sex.
“Infertility is a global public health issue, and it is important that research focuses on addressing risk factors,” says Arendt.
The study included 9232 adult sons and daughters, of which 9.4% struggled with infertility.
The research team found that adult sons were 1.4 times more at risk of infertility if their mothers had a body mass index (BMI) of over 25 kg/m2 before their son was born, compared to mothers with a BMI of 18.5–24.9kg/m2.
Interestingly, they found no association between pre-pregnancy weight of mothers and infertility in adult daughters. Additional studies are required to investigate the one-sided trend of this particular risk factor.
- “Infertility” refers to no success in conceiving for a year or longer and is considered a global health issue
- Infertility affects 1 in 9 Australian couples
- There’s an equal chance that infertility is due to reproductive issues of either the male or female
“We know that children born to mothers in the overweight or obesity weight range face higher risks of several adverse outcomes, both in the short and long term,” says Arendt.
“These findings add to evidence that weight during pregnancy may also affect male future reproductive health; however, the findings need to be corroborated in future studies.”
This is a relatively small study with interesting implications, especially as it suggests that the potential cause of infertility in some of the men occurs so long in the past. Further studies will help to determine whether this is a world-wide trend.
This study was recently published in the journal Acta Obstetricia et Gynecologica Scandinavica.
Dr Deborah Devis is a science journalist at The Royal Institution of Australia.
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