A new study, published in The FASEB Journal, suggests that fetuses who are exposed to low levels of oxygen during development may have advanced ovarian aging and a lower number of eggs available for future reproduction.
To examine the effects of low oxygen levels on developing fetuses, researchers from the Metabolic Research Laboratories at the University of Cambridge exposed pregnant rats to 13 percent oxygen levels, instead of the standard 21 percent found in the air. The rats were exposed to low oxygen levels from day 6 to day 20 of their pregnancies. The reproductive tracts of the female pups were then examined at 4 months of age.
The female pups that were exposed to low levels of oxygen during development were found to have a lower number of ovarian follicles (eggs) in their ovaries compared to pups exposed to normal oxygen levels. The telomere lengths in the ovarian tissue of pups exposed to low oxygen levels were also found to be shorter than the pups in normal oxygen levels. Telomeres are found at the end of chromosomes and as we age, the telomeres become shorter. The shorter telomeres in the pups exposed to low oxgyen indicated advanced ovarian aging.
For humans, exposure to low oxygen levels during development can be caused by numerous factors, such as smoking, illicit drug use, maternal obesity, and pre-eclampsia. These conditions are already known to have effects on the general health of future offspring, but this study is the first to show that future fertility may also be affected.
“Now that we’ve seen a link between hypoxia and fertility problems in rats, we know what to look for in women,” said Dr. Catherine Aiken from the University of Cambridge. “If the same turns out to be true for them, then women at risk will be able to take action: by having children earlier in life or looking to assisted reproduction, such as IVF, there should be no reason why these women cannot have children.”