Week 20: The halfway point

Halfway into your pregnancy, or 18 weeks after conception, you might be able to feel your baby's movements (quickening). Your baby is regularly sleeping and waking. He or she might be awakened by noises or your movements.

By now your baby might be about 6 1/3 inches (160 millimeters) long from crown to rump and weigh more than 11 ounces (320 grams).

Week 21: Baby can suck his or her thumb

Twenty-one weeks into your pregnancy, or 19 weeks after conception, your baby is completely covered with a fine, downy hair called lanugo. The lanugo helps hold the vernix caseosa on the skin.

The sucking reflex also is developing, enabling your baby to suck his or her thumb.

Week 22: Baby's hair becomes visible

Twenty-two weeks into your pregnancy, or 20 weeks after conception, your baby's eyebrows and hair are visible. Brown fat also is forming, the site of heat production.

For boys, the testes have begun to descend.

By now your baby might be 7 1/2 inches (190 millimeters) long from crown to rump and weigh about 1 pound (460 grams).

Week 23: Fingerprints and footprints form

Twenty-three weeks into your pregnancy, or 21 weeks after conception, your baby begins to have rapid eye movements. Ridges also form in the palms of the hands and soles of the feet that will later create the foundation for fingerprints and footprints.

Your baby might begin hiccupping, causing jerking movements.

Week 24: Baby's skin is wrinkled

Twenty-four weeks into your pregnancy, or 22 weeks after conception, your baby's skin is wrinkled, translucent and pink to red because of visible blood in the capillaries.

By now your baby might be about 8 inches (210 millimeters) long from crown to rump and weigh more than 1 1/3 pounds (630 grams).

Week 25: Baby responds to your voice

Twenty-five weeks into your pregnancy, or 23 weeks after conception, your baby might be able to respond to familiar sounds, such as your voice, with movement.

Your baby is spending most of his or her sleep time in rapid eye movement (REM), when the eyes move rapidly even though the eyelids are closed.

Week 26: Baby's lungs develop

Twenty-six weeks into your pregnancy, or 24 weeks after conception, your baby's lungs are beginning to produce surfactant, the substance that allows the air sacs in the lungs to inflate — and keeps them from collapsing and sticking together when they deflate.

By now your baby might be 9 inches (230 millimeters) long from crown to rump and weigh nearly 2 pounds (820 grams).

Week 27: 2nd trimester ends

This week marks the end of the second trimester. At 27 weeks, or 25 weeks after conception, your baby's nervous system is continuing to mature. Your baby is also gaining fat, which will help his or her skin look smoother.

July 08, 2017 See more In-depth