In Utero Development of a Baby

Fetal development is an amazingly complex process. Although all you might see from the outside is a growing belly, every day brings new and exciting changes in the body of your baby.

Months One and Two

By one month, baby is ¼ inch long and her heart, digestive system, backbone and spinal cord are forming. At eight weeks, baby is 1 1/8 inches long and has a functioning heart. His ears, teeth, lips, nose, eyes and tongue are beginning to form.

Months Three and Four

At 12 weeks, baby is 2 ½ to 3 inches long and weighs between 1/2 and 1 oz. Her heartbeat can be heard using a Doppler around week 10. Nearly 7 inches long at 16 weeks, baby is developing his reflexes and may suck his thumb.

Months Five and Six

By 20 weeks, your baby weighs about 1 lb. and has hair growing on her head, eyebrows and eyelashes. You may now feel her moving. At 24 weeks she is 11 to 14 inches long and nearly 2 lbs., and begins opening her eyes.

Months Seven and Eight

By 28 weeks, baby weighs 2 ½ to 3 ½ lbs. and now has taste buds. Her organs are maturing and her body is gaining fat. By 32 weeks, body and brain are growing quickly and baby weighs 4 to 6 lbs.

Month Nine

At 38 weeks, baby's lungs are now mature and he may seem less active as the body prepares for birth.

References

• Sutter Health

Resources

• BabyCenter.com