How many gestation weeks are there?

40 weeks in humans

It is widely known the fact that gestation is the carrying of an embryo or fetus inside female viviparous animals, including mammals, as well as some non-mammalian species.  It is interesting to know that mammals during pregnancy can have one or more gestations at the same time.  The main idea is that in humans, birth normally occurs at a gestational age of about 40 weeks.  Needless to say, a normal range is from 38 to 42 weeks.  Keep in mind that the time interval of a gestation is called the gestation period.