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Spark of Life

A new way to detect healthy egg cells.

By Katherine KorneiDecember 19, 2016 6:00 AM
Sperm & Egg - Science Source
Flagging viable sperm is easier than spotting healthy eggs. (Credit: Don W. Fawcett/Science Source)


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For potential parents struggling with fertility, bright eggs might be good eggs. Scientists at Northwestern University announced in April that they had recorded flashes of light from human eggs that may be an indicator of egg quality.

Fertility clinics can identify healthy human sperm based on their movement and structure, but evaluating eggs has always been much less straightforward. Now, thanks to these flashes, that task could get a lot easier.

DSC-E0217_07 eggs releasing zinc
Researchers can see which human eggs are healthiest by their release of zinc, shown in halolike bursts in timelapse images, at fertilization. (Credit: Duncan et al. 2016 Scientific Reports. Reprinted by permission from Macmillan Publishers Ltd.)

The sparks are associated with eggs expelling the mineral zinc after they’re injected with spermlike enzymes. (Federal law prohibits researchers from fertilizing eggs with actual sperm.) The flashes, which appear as a halo around each egg, happen a few minutes after fertilization.

Previous mouse experiments demonstrated that these flashes were more intense for higher-quality fertilized eggs. If these “fertility fireworks” are also indicative of egg quality in humans — a question the Northwestern team intends to investigate — doctors could non-invasively select the best eggs for in vitro fertilization.

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