1. Bri Hearn and Dan Friedman

2. After fertilization, the sperm penetrates the egg, creating a zygote. A newly conceived human stays as a zygote for about four days. This is the beginning of the first trimester of pregnancy. The zygote becomes a morula once the new life travels down the fallopian tube for a couple of days while dividing into cells. Following the morula stage, the fertilized egg then becomes a blastocyst. A blastocyst consists of single, circular layer of cells enclosing a rather sturdy, central chamber. The blastocyst will eventually go the the uterus, and become an embryo.

3. The embryo goes through a stage of basic growth, such as development of the brain, heart, and spinal cord. By the fourth to fifth week of pregnancy, the limbs of the baby become visible, and he or she has a distinguishable heart beat. Blood also begins to flow through the veins of the embryo, which is now about a quarter of an inch long.

4. By week 6, the development of the nose, jaw, and lungs begins, along with the budding of fingers and toes. An audible heartbeat can now be heard. By week 7, all the vital organs begin to form, and hair follicles begin to develop. The embryo is about a half inch in length.

5. By the eighth week, most organs and features in an adult are present in the embryo. The embryo’s muscles can now contract, and bones are forming. The embryo is about an inch and weighs as much as a bean. Facial features continue to mature, ending the embryonic period and starting the fetal period. By the ninth week, the embryo, now a fetus, grows to about three inches

6. By your fourteenth week of pregnancy, the second trimester is reached. For the next two weeks, thin hairs begin to form on the fetus’s head, called lanugo, and the new individual’s unique fingerprint develop. The fetus begins to move around, causing the mother to feel “kicking” in her abdomen. The unborn baby now is about six inches in length and weighs about four ounces.

7. The fetus’s eyebrows and eyelashes finally grow in, along with finger and toe nails. The baby also develops vernix, a white gooey substance that covers the unborn baby’s skin to protect him or her from the amniotic fluid. The fetus is now about eight inches in length and 12 ounces in weight.

8. Lanugo now completely covers the unborn baby’s body. The fetus’s skin becomes less transparent with fat beginning to develop. The eyes, pancreas, and liver finally develop completely. The unborn baby is now about ten to eleven inches and weighs about a pound.

9. The brain will continue to quickly grow over the next two weeks, and the nervous system can now develop some functions. The fetus is now around fourteen inches tall and weighs a little more than two pounds. If there is a problem at this point in time with your pregnancy, the baby can be delivered with the help of medical technology.

10. By the twenty-seventh week of pregnancy, the third trimester is reached. For the next few weeks, the unborn baby continues to fill out, reaching fifteen to seventeen inches in length and four to four and a half pounds by the thirty-second week of pregnancy. The fetus’s lungs are not fully functional, but rhythmic breathing begins to occur.

11. The fetus’s languo falls off at this point, now weighing between six to seven pounds and reaching sixteen to nineteen inches in length. The unborn baby will move to the “head down” position to prepare for delivery.

12. From this point forward, the phases of pregnancy are complete and the baby is ready to enter the new world. At this point in time, the fetus should be nineteen to twenty-one inches long and seven to nine pounds.