The term "gestation period" refers to the time between fertilization and birth for a pregnant animal or human. Many synonyms can be used for this phrase to enrich your writing. Some common synonyms of gestation period include pregnancy duration, incubation period, carrying time, and birthing cycle. Other ways to describe the same concept would be to use terms like prenatal term, antenatal period or embryonic development. These alternative phrases might be useful when you need to avoid repetition, or simply to enhance your text with more descriptive and varied vocabulary. Overall, no matter what words you choose to use, the gestation period remains a critical aspect of reproduction in animals and humans alike.