If you could look in to the womb or uterus one month after conception, you would see a very small piece of human tissue. It's difficult to imagine that this will grow into a baby. The fetus is only a quarter inch long and weighs maybe one-hundredth of an ounce. You could see a little tail and the beginning formation of the vital organs. Within 5 to 6 weeks the heart, brain, spinal cord, nervous system, and digestive tract is forming.

At two months human features like ears, eyes, nose, and mouth are easily identifiable. Fingers, toes, knees, and elbows are forming on developing arms and legs. Reproductive organs are forming, but it is difficult to distinguish male from female. The fetus has grown to one inch, but still weighs less than a gram.

At three months tooth buds are identifiable in the jaw bone and toenails and fingernails can be seen. Additional organs are forming and the baby weighs a full ounce and is 3 inches in length. It is still difficult for the mother to sense movement.

At four months the fetus weighs about ¼ pound and is several inches long. A few hairs are visible on the head and the body is covered in a very fine hair. Vital organs have formed and many are functioning. A fluttering can be felt as the baby wiggles its arms and legs. Fetal heartbeat is easier to detect.

At five months the baby is almost a foot long and weighs 24 ounces (1.5 pounds). The baby is usually moving regularly and often by now. Facial expressions, eyelashes, eyebrows, and hair are developed.

At six months the baby looks like a tiny human being. It has developed a covering called vernix caseosa (cheesy varnish) that protects its skin from the fluid environment. It is growing very fast and is 15 inches long and weighs 2 ½ pounds.

By seven months the baby is preparing for independent existence. Systems and nerve cells mature and the baby gains weight. By now the baby weighs 4 pounds and is over 16 inches long. In the 8th and 9th months the baby is adding fat for survival in the world outside. The lungs are the last organs to fully mature. Once the respiratory system has matured, it's time for the baby to be born. At full term the baby should be about 7 ½ pounds and at least 17" long.

A more detailed explanation of fetal development can be seen in program #00130, "FETAL AND MATERNAL DEVELOPMENT".