Stages of Pregnancy
3rd Trimester Baby
The 3rd Trimester Baby: 28 Weeks to Birth
During the third trimester (the last three months of pregnancy) the baby could survive if born before it is full term. Your due date is estimated based on 40 weeks gestation. If your baby is born before 37 weeks gestation, it is considered to be preterm (born early). If your baby is born after 42 weeks gestation, it is said to be post term. The earlier a baby is born, the greater the need for special care to decrease the risks from a preterm birth. The closer to full term, the more able the baby is to cope with the birth process and life outside the uterus.
(Please note that although the term “baby” is used throughout this website, during the first 7 weeks the actual term for your developing baby is an “embryo,” and from week 8 until birth it is a “fetus.”)
Time |
Weight and Length |
Events |
28 weeks |
35–37 cm (14 in.) |
Your developing baby’s body is still lean but the skin is less wrinkled and red. The baby can now store iron, calcium, and other nutrients. Your baby can hear and respond to sounds.  28 weeks, 35-37 cm (14 in.) |
32 weeks |
40–42 cm (16 in.) |
Your baby’s skin is pink and smoothes out as the fat forms under it. Your baby develops a sense of taste and becomes aware of sounds outside your body. The male baby’s testicles begin to drop into the scrotum. The pupils in the baby’s eyes can react to light. |
36 weeks |
45–47 cm (18 in.) |
Your baby’s body is rounded and usually plump. The downy hair on the baby’s body begins to disappear. The skin is smooth, pink, and covered with a grayish‑white cheese‑like substance called vernix. The baby continues to increase the store of antibodies and is able to resist some diseases. Usually your baby can safely be born at this age. |
40 weeks |
45–55 cm (18–22 in.) |
Head hair is usually present. The testicles of male babies are now in the scrotum, and the labia majora of female babies are developed. |
40 – 42 weeks |
weight will increase |
The fontanels (soft spots on the head) are becoming smaller and the skull bones are growing firmer and less flexible. The skin may become looser as the fat layer decreases. Skin is also drier and may have small cracks as the amount of vernix decreases. Nails may be long. |
More than 42 weeks |
weight will increase |
The skin continues to get drier and will have cracks as the amount of vernix continues to decrease. |
