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Second Trimester Infant Development
A look at how your baby changes from week 14 to week 25.
by: Dr. Peter Doubilet and Dr. Carol Benson
In This Article
Second Trimester Development
- At 15 weeks, your baby can make facial expressions and may even suck her thumb.
- By 17 weeks, an ultrasound should be able to show you the sex of your baby.
- By 19 weeks, your baby will be able to hear your voice if you read her a story or sing a song.
- Your baby will measure a little over a foot in length and will weigh more than one pound by end of the second trimester.
ften referred to as "the honeymoon phase," the second trimester lies between the first, in which women are often plagued by morning sickness, and the third, in which moms are often carrying so much extra weight that they're ready for the pregnancy to be over. And, when it comes to ultrasounds, the second trimester is the most exciting time for parents. The baby's face, limbs, and internal organs are now large enough to see in exquisite detail. And, if your baby cooperates during your ultrasound, you may even be able to determine its sex.
Weeks 14 to 16
In the first two weeks of the second trimester, your baby is about four inches long, or the length of a bell pepper (measured from the top of the head to the bottom of the rump). The body is now growing faster than the head so the fetus is becoming more proportional to what your baby will look like once she is born. Your little one is gaining weight quickly and is now about two or three ounces.
During this stage, the baby is still small enough that ultrasound can show a full body view on the screen, but big enough that details of the face are quite apparent. Although you may not be able to make out her expressions, she can now squint, frown and grimace. You may even see her sucking her thumb.
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| 15-week 2D ultrasound image of baby lying on her back and looking upward. |





