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Premature Babies Week by Week


Updated May 29, 2014

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

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Premature Babies Born at 25-26 Weeks
Caleb, a preemie born at 26 weeks.

Caleb, a preemie born at 26 weeks.

Image courtesy of Elizabeth Locke

By 25 to 26 weeks, premature babies weigh about 1 1/2 to 2 pounds, and are about 9 inches long when measured from head to bottom. Babies born at this time are called micro preemies, and they face long NICU stays and have many health issues related to prematurity.

By 26 weeks gestation, premature babies' lungs are starting to develop alveoli, the air sacs that allow gas exchange. Although they are still too young to breathe without help, this is a major milestone! Other developmental milestones for 25 and 26 weekers include the development of the startle reflex - a baby born at this time will startle at loud noises. Footprints and fingerprints are also developing.

Read more:

  1. About.com
  2. Health
  3. Preemies
  4. Preemie Milestones
  5. Premature Babies Born at 25-26 Weeks

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