Gestation

A gestation is the carrying of an embryo or fetus inside a female of certain types of animals.

In female animals that undergo a pregnancy, that pregnancy can have one or more gestations at the same time. In the case of a pregnancy with multiple gestations, the offspring that are gestated by their mother are twins of each other.

For example, bitches of dogs usually have multiple ovulations in a single estrus cycle, and, when the secreted ova get fertilized, the bitches gestate multiple offspring in one single pregnancy.

The time interval of a gestation is called a gestation period.