(the period of) the development of a child or young animal while it is still inside its mother's body

The baby was born prematurely at 28 weeks gestation. 胎儿在怀孕的第28周早产。

The period of gestation of rats is 21 days. 老鼠的妊娠期是21天。

(the period of) the development of ideas, thoughts, or plans

The project had a very long gestation period. 这个方案经过了很长时间的酝酿。