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Erin Walters

Fetal Development In Third Trimester

Two trimesters down, one to go! Find out what developmental changes baby goes through in the home stretch.

In the third trimester (weeks 28 through delivery), most major development has already happened. This is the time for baby to hang around gaining weight—about half a pound each week, at least until week 37.

Baby is still kicking and stretching, though her movement might slow down as she gets more cramped in the tight space of your belly. The coating of fine hair on her body (called lanugo) sheds away and the bones get nice and hard—except the skull, which stays soft and flexible for the big squeeze through your birth canal.