Second Trimester Fetal Development

The growth of your baby is a continuous process that often conveys a sense of awe. The following information is divided into pregnancy’s three trimesters to help you understand your baby’s rapid growth. Milestones in fetal development are also highlighted. (Sizes and weights are approximate.)

Month 4

At the end of 4 months:

• Baby is 6-1/2 to 7 inches long.
• Weight is about 6 to 7 ounces.
• Baby is developing reflexes, such as sucking and swallowing, and may begin sucking thumb.
• Tooth buds are developing.
• Sweat glands are forming on palms and soles.
• Fingers and toes are well defined.
• Gender is identifiable.
• Skin is bright pink, transparent and covered with soft, downy hair.
• Although recognizably human in appearance, the baby would not be able to survive outside the mother’s body.

Month 5

At the end of 5 months:

• Baby is 8 to 10 inches long.
• Weight is about 1 pound.
• Hair begins to grow on baby’s head.
• Soft woolly hair called lanugo covers baby’s body. Some may remain until a week after birth when it is shed.
• Mother begins to feel fetal movement.
• Internal organs are maturing.
• Eyebrows, eyelids and eyelashes appear.

Month 6

At the end of 6 months:

• Baby is 11 to 14 inches long.
• Weight is about 1-3/4 to 2 pounds.
• Eyelids begin to part and eyes open sometimes for short periods of time.
• Skin is covered with protective coating called vernix.
• Baby is able to hiccup.