A recent study conducted by researchers at the University of Connecticut Health Center and published in the journal Science found a receptor in mice that they believe keeps eggs in arrested development until they are ready to be fertilized. Although a similar study on humans needs to be conducted, the researchers believe that there’s a similar receptor in human eggs.

The process that reduces the chromosome numbers in the eggs to ready them for fertilization is called meiosis. Meiosis occurs in stages, starting when the eggs are first formed while the female baby is still in the womb. The process is not completed until each egg is released. This usually happens when the woman ovulates and menstruates.

The study is significant because scientists have long known that eggs are held in suspended meiosis, but they didn’t know exactly why. Now they do. When the researchers removed the receptor, the eggs resumed meiosis without being released from the ovary in the usual manner. Although the scientists do not know what signals the receptor to pause meiosis, they do believe that it comes from the surrounding cells in the ovary. When the hormones surge to trigger ovulation, it helps to release the egg from the ovary and break its contact with the surrounding cells.

The next step will be to find the receptor in humans and to locate the signal that activates the receptor. The findings of this study may be important in understanding unexplained infertility, chromosomal abnormalities, and even early pregnancy loss.