The time period from conception to birth is called

It is known by the name of gestation

Explanation:

Gestation or gestational age is the period of time between conception and birth. At this time, the baby grows inside the womb of his mother. Gestation or gestational age is measured in weeks, for example, a normal pregnancy can be from 38 to 42 weeks.

Babies born before week 37 are considered premature and if they are born after week 42 they are called post-mature.

2%? i tried finding the exact sorry if it's not 100% correct ; -;