Baby Chris is 24 Weeks Old

Graphic via the Endowment for Human Development

[This is part 25 of a multi-part series chronicling a pregnancy through the lens of “Baby Chris.” Click here for other parts.]

24 weeks after fertilization (26 weeks LMP), Baby Chris is 14 inches long and weighs 1 and 3/4 pounds.

The major milestone this week is that Baby Chris has developed the ability to hear. Outside sounds are of course muffled, but Baby Chris can easily listen to sounds from within the mother’s body, such as her speech and heartbeat. This is why newborns express a preference for their mother’s voice over other people’s voices.

Remember when Baby Chris’s eyelids fused together back in week 9? They have finally un-fused, allowing Baby Chris to open his or her eyes. This also enables the “blink-startle response,” as described by the Endowment for Human Development:

By 24 weeks, the eyelids reopen and the fetus exhibits a blink-startle response. This reaction to sudden, loud noises typically develops earlier in the female fetus. This response is very much like what adults and children exhibit in the same situation.

When exposed to a loud noise, the fetal heart rate increases, as does the rate of movement. Excessive fetal swallowing following exposure to loud noise may lead to a loss of amniotic fluid. Possible long-term consequences for fetuses are the same as consequences for children and adults: hearing loss and deafness.

The fetus also responds to pressure, movement, pain, hot and cold, taste, and light.

For more on Baby Chris’s journey from conception to birth, download the free See Baby app!