Information on Fetus Growth

The fetal development of a human baby takes place over three three-month periods called trimesters. During each trimester, the fetus develops specific characteristic that can be monitored as he approaches maturity.

First Trimester

• During the first trimester, the fertilized egg implants itself in the uterus, the embryo divides into two halves (one becomes to fetus, the other becomes the placenta), the heart begins beating, and the umbilical cord begins to form.

Second Trimeseter

• The embryo is now know as a fetus. During this trimester, the risk of miscarriage becomes significantly less. Organs and features begin to form, and the baby's senses begin developing. The baby begins to hear and to have a sense of touch.

Third Trimester

• During this trimester, the baby's retinas develop, and she opens her eyes. The baby also puts on body fat, begins using her lungs and is born.

Gender

• You can determine the gender of the baby by ultrasound after his reproductive organs develop during the second trimester.

Length and Weight

• In the first weeks of pregnancy an embryo is less than 1 inch long and weighs less than 1 oz. He will grow into a fetus starting at about 10 inches long and 10 oz. and will eventually develop into a newborn baby averaging about 20 inches and just over 8 pounds.

Hair Growth

• A fetus begins to grow hair around week 22. Eyelashes and eyebrows develop first, followed by hair on the baby's head. At first, fetal hair has no pigment and appears bright white