Tell or Say please, that such at pregnancy " a uterus in a tonus ". Than it is m....

[Natalia]

Tell or Say please, that such at pregnancy " a uterus in a tonus ". Than it is m.. It is caused or called and than threatens a fetus?

[Pasenjuk A.M.]

It means, more often, that a uterus which is as a matter of fact a muscular bag, is strained and ready at any moment to start to be reduced, that can lead to an abortion.