©2018 WebMD, Inc. All rights reserved. eMedicineHealth does not provide medical advice, diagnosis or treatment. See Additional Information.

Pregnancy and Fetal Development

Picture of Second Trimester (24 Weeks)

Picture of Second Trimester (24 Weeks)

The second trimester of pregnancy refers to a fetus at 24 weeks gestational age. At this stage, the baby is about 12 inches long and weighs approximately 1 1/2 pounds. Taste buds, footprints, and fingerprints form. The baby's bone marrow starts to manufacture blood cells. The infant experiences sleep and wake cycles. Hair begins to grow on the head. Lungs develop but are not yet functional. The baby begins to have hand and startle reflexes. In males, testicles begin to descend from the abdomen into the scrotum. In females, the ovaries and uterus are in the correct anatomical position and the ovaries contain a lifetime supply of eggs.

Image Source: Neil Bromhall / Genesis Films / Photo Researchers, Inc.

Text References: American Pregnancy Association: "Pregnancy Week 24"

WomensHealth.gov: "Stages of Pregnancy"