Scientists have discovered an enzyme that acts as a "fertility switch" and say their findings could help treat infertility and miscarriage and may also lead to new contraceptives.

A study in the journal Nature Medicine reports that researchers at Imperial College London have found that high levels of a protein called SGK1 are linked with infertility, while low levels of it make a woman more likely to have a miscarriage.

Enzymes are proteins that catalyze, or increase the rates of, chemical reactions.

Jan Brosens, who led the study at Imperial and is now at Warwick University, says its results suggest new fertility and miscarriage treatments could be designed around SGK1.

"I can envisage that in the future, we might treat the womb lining by flushing it with drugs that block SGK1 before women undergo IVF (in-vitro fertilization)," he says.

"Another potential application is that increasing SGK1 levels might be used as a new method of contraception."