HealthPartners - Your guide to pregnancy

MONTH [WEEKS 21-24] 6

• The baby may get very active for a day or two, then settle down for a few days • The basic structure of the eye is forming and is positioned correctly on the head • The lungs are fully formed but not yet functional • The brain continues to develop rapidly

SIZE About 12" long

WEIGHT More than 1½ pounds

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• With special care, babies born at this stage of development can survive • Your baby now kicks and stretches in response to sounds • The eyelids and nostrils have opened, and the baby is able to sense light, smell, and taste • Lungs form tiny air sacs called alveoli, and the baby starts making basic breathing movements • The skin thickens and becomes dull; spinal structure matures and bones harden • Different areas of the brain are continuing to develop • The baby has reddish, wrinkled skin, is very thin, and will put on needed fat until birth • The eyes are beginning to open, and the eyelids and eyebrows are fully formed • Real hair begins to grow; fingernails have grown to the ends of the fingers • Babies sometimes suck on their thumbs and make grasping motions with their hands • Your baby can now hear you talk, read, and sing

MONTH [WEEKS 25-28] 7

SIZE About 15" long

WEIGHT About 2½ pounds

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MONTH [WEEKS 29-32] 8

SIZE About 17" long

WEIGHT A little more than 4 pounds

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• Babies born during this month are still premature but have an excellent chance of survival

MONTH [WEEKS 33-36] 9

• The baby’s bones and nails are getting harder • All vital organs (except the lungs) are mature

• Wrinkles disappear as fat begins to deposit under the skin • The lanugo hair begins to shed, but some may remain on the baby’s back and shoulders • Many babies are now moving into birthing position • The baby’s skull remains soft and flexible for birth

SIZE About 18½" long

WEIGHT About 6 pounds

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• The baby usually settles into a head-down position and waits for you to go into labor • The baby’s lungs are now fully mature and ready to function • Regular fetal sleep patterns are developing that will continue after birth • Your baby adds fat tissue to protect their vital organs and keep warm • They also start storing iron in their liver to get ready for life after they are born • The waxy, white vernix on the baby’s skin and lanugo hair are almost completely gone

MONTH [WEEKS 37-40] 10

SIZE About 20" long

WEIGHT About 7½ to 8 pounds (average)

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Your Guide to A Healthy Pregnancy

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