The astonishing beginning and subsequent development of the human embryo and its transition to the category of fetus at roughly eight weeks is known to medical scientists in stunning detail. For forty weeks these events are hidden from the outside world. At birth the child makes its grand entry to the vision of outside observers, the world of conventional photography, and the world of unmuffled sound. The newborn experiences an immediate need for an independent food and air supply. With dramatic suddenness the infant transitions from the silent prenatal development venue to the bustling activity of the world of the nursery.
The first eight weeks are crucially important. The foundation for cellular organization is laid in the tiny embryo during the first few weeks following conception. This is an incredibly eventful and delicate time interval. At four weeks the embryo is smaller than a grain of rice. Many of the 220 types of body cells navigate their way to their proper positions in the newly forming human body. At eight weeks every body organ is in place. Bones have begun to replace cartilage, fingerprints form, and the baby can begin to hear. The baby has grown to one inch in length and “humanity now covers the embryo’s countenance.”
The body structure at eight weeks is visibly locked in place. Hereafter the fetus mainly increases in size and completion of already formed bodily features. The National Right to Life Committee (NRLC) website link on “Fetal Development” details the transition from one inch in length and 1/8 ounce in weight to the average birth length of 18-20 inches and average body weight of seven pounds.
In the following paragraphs we quote information published by NRLC on fetal development prior to birth.
During weeks nine and ten teeth begin to form. The baby can turn its head, frown, and hiccup. Weeks ten and eleven find the baby able to “breathe” amniotic fluid and urinate. Objects placed in its hand may be grasped. All organ systems are functioning. The baby has a skeletal structure and circulation.
In week twelve the baby is three inches long, weighs one ounce, and has all the parts necessary to experience pain, including nerves, spinal cord, and thalamus. Its vocal cords are complete. The baby can suck its thumb. At fourteen weeks the heart pumps several quarts of blood through its body every day. At sixteen weeks the baby is four to five inches long, weighs three ounces, possesses a complete skeleton, and has an adult’s taste buds.
At the close of the fourth month the baby has grown to eight to ten inches in length and weighs one half pound. Bone marrow is beginning to form. The heart is pumping 25 quarts of blood each day. The baby recognizes its mother’s voice at twenty weeks. During months five and six the baby practices breathing by inhaling amniotic fluid into its developing lungs. The baby grasps at the umbilical cord when it feels it. A mother feels movements from her baby which has achieved twelve inches in length and a weight of one and one-half pounds.
During months seven through nine the baby opens and closes its eyes. It makes use of four of its five senses--vision, hearing, taste, and touch. It knows the difference between waking and sleeping and can relate to the moods of the mother. The baby’s skin begins to thicken, and a layer of fat is produced and stored beneath the skin. Antibodies are built up, and the baby’s heart pumps 300 gallons of blood per day. Approximately one week before birth the baby stops growing and descends, head down, into the pelvic cavity.
The first eight weeks of gestation is the time frame most shrouded in mystery. Professionals in embryology have written voluminously on chemical and physical processes taking place in the miniscule, kernel-sized embryo of the first month of pregnancy. In the first four weeks the embryo becomes ten thousand times larger than the fertilized egg but it remains barely visible. We repeat the colorful imagery in one volume on reproduction: “Nothing so puzzles embryologists as the way in which cells outfit themselves and trek about to settle different regions of the embryo.” We hasten to explain the cells’ “trek” occurs in a tiny piece of embryological tissue.
At the end of two months the embryo stage concludes and the fetus stage begins. The foundation of the human frame has been laid. The seven-month fetus stage mostly builds on a structure already in place after two months. Interrupting the events of a healthy pregnancy at any stage is a procedure bringing grief to ethical parents who think profoundly. More significant is the grief this procedure brings to the Creator who planned and created life and sustains it from moment to moment.