What is the meaning and the difference between this.prenatal stage, perinatal stage, And postnatal stage

The perinatal stage is a more specific period that includes the late stage of prenatal development (typically from around 28 weeks of gestation) and the early days after birth (up to about 7 days). It focuses on the critical transition from fetal life to newborn life.

The postnatal stage refers to the period after birth. It encompasses infancy, childhood, adolescence, and adulthood, covering all stages of development from newborn to old age.

The key difference is the timing relative to birth: prenatal is before, perinatal is the transition around birth, and postnatal is after birth.