The Facts of Prenatal Development


Is it a human being?

"From the moment a baby is conceived, it bears the indelible stamp of a separate distinct personality, an individual different from all other individuals." Ultrasound pioneer, Sir William Liley, M.D. 1967.

"After fertilization has taken place a new human being has come into existence. This is no longer a matter of taste or opinion. Each individual has a very neat beginning, at conception." Dr. Jerome Lejeune, genetics professor at the University of Descartes, Paris. He discovered the Down syndrome chromosome.

"It is scientifically correct to say that an individual human life begins at conception." Professor M. Matthews-Roth, Harvard University Medical School.

"By all the criteria of modern molecular biology, life is present from the moment of conception." Professor Hymie Gordon, Mayo Clinic.

When does the heart begin to beat?

At 18 days [when the mother is only four days late for her first menstrual period], and by 21 days it is pumping, through a closed circulatory system, blood whose type is different from that of the mother. J.M. Tanner, G. R. Taylor, and the Editors of Time-Life Books, Growth, New York: Life Science Library, 1965, p.

When is the brain functioning?

Brain waves have been recorded at 40 days on the Electroencephalogram (EEG). H. Hamlin, "Life or Death by EEG," JAMA, Oct. 12, 1964, p. 120

Brain function, as measured on the Electroencephalogram, "appears to be reliably present in the fetus at about eight weeks gestation," or six weeks after conception. J. Goldenring, "Development of the Fetal Brain," New England Jour. of Med., Aug. 26, 1982, p. 564

How early do some organs form?

The eye, ear and respiratory systems begin to form four weeks after fertilization. K. Moore, Before We Were Born, 3rd ed., 1989, p. 278

And function?

Very early, e.g., glucagon, a blood sugar hormone, has been demonstrated in the fetal pancreas 6 weeks after fertilization, and insulin by 7 to 8. F. Cunningham, "Pancreas," William’s Obstet., 19th ed., 1993, p. 183-4

Thumbsucking has been photographed at 7 weeks after fertilization. W. Liley, The Fetus As Personality, Fetal Therapy, 1986, p. 8-17

When does the developing baby first move?

"In the sixth to seventh weeks. . . . If the area of the lips is gently stroked, the child responds by bending the upper body to one side and making a quick backward motion with his arms. This is called a ‘total pattern response’ because it involves most of the body, rather than a local part." L. B. Arey, Developmental Anatomy (6th ed.), Philadelphia: W. B. Sanders Co., 1954

At eight weeks, "if we tickle the baby’s nose, he will flex his head backwards away from the stimulus." A. Hellgers, M.D., "Fetal Development, 31," Theological Studies, vol. 3, no. 7, 1970, p. 26

Another example is from a surgical technician whose letter said, "When we opened her abdomen (for a tubal pregnancy), the tube had expelled an inch-long fetus, about 4-6 weeks old. It was still alive in the sack. "That tiny baby was waving its little arms and kicking its little legs and even turned its whole body over." J. Dobson, Focus on the Family Mag., Aug. ’91, pg. 16

When are all her body systems present?

By eight weeks (two months). Hooker & Davenport, The Prenatal Origin of Behavior, University of Kansas Press, 1952

When do teeth form?

All 20 milk-teeth buds are present at six and a half weeks."Life Before Birth," Life Magazine, Apr. 30, 1965, p. 10

And include dental lamina at 8 weeks. Med. Embryology, Longman, 3rd Ed., 1975, p. 406

How about nine weeks?

At nine to ten weeks, he squints, swallows, moves his tongue, and if you stroke his palm, will make a tight fist.

By nine weeks he will "bend his fingers round an object in the palm of his hand." Valman & Pearson, "What the Fetus Feels," British Med. Jour., Jan. 26, 1980

When does he start to breathe?

"By 11 to 12 weeks (3 months), he is breathing fluid steadily and continues so until birth. At birth, he will breathe air. He does not drown by breathing fluid with-in his mother, because he obtains his oxygen from his umbilical cord. This breathing develops the organs of respiration." "Life Before Birth," Life Magazine, Apr. 30, 1965, p. 13

"Maternal cigarette smoking during pregnancy decreases the frequency of fetal breathing by 20%. The ‘well documented’ higher incidence of prematurity, stillbirth, and slower development of reading skill may be related to this decrease." 80 F. Manning, "Meeting of Royal College of Physicians & Surgeons," Family Practice News, March 15, 1976

"In the 11th week of gestation fetal breathing is irregular and episodic. As gestation continues, the breathing movements become more vigorous and rapid." C. Dawes, "Fetal Breathing: Indication of Well Being," Family Practice News, Mar. 16, 1976, p. 6

Episodic spontaneous breathing movement have been observed in the healthy human fetus as early as ten weeks gestational age. Conners et al., "Control of Fetal Breathing in the Human Fetus," Am J. OB-GYN, April ‘89, p. 932

When can she swallow?

At 11 weeks. Valman & Pearson, British Med. Jour., "What the Fetus Feels," 26 Jan. 1980, p. 233

What of detailed development, like fingernails and eyelashes?

Fingernails are present by 11 to 12 weeks; eyelashes by 16 weeks. Fingerprints are completely established during the fourth month of gestation.  Hamilton et al., Human Embryology, Fourth Ed., 1972, p. 567

At what point are all her body systems working?

By 11 weeks. "Life Before Birth," Life Magazine, Apr. 30, 1965, p. 13

How does the size of the baby increase in weight?

At 12 weeks (three months) she weighs about 30 gm (1.0 ounce); at 16 weeks about 170 gm (6 ounces); and at 20 weeks (four months), approximately 454 gm (one pound).

When is taste present?

"Taste buds are working between 13 and 15 weeks gestation" (11 to 13 weeks after conception). Mistretta & Bradley, Taste in Utero, 1977, p. 62 Bradley et al., "Dev. Taste Buds . . . ," J. Anat. 101 (4) 1967, p. 743-752

How about hearing?

"Auditory sense is present in the infant 24 weeks before birth [14 weeks after conception]. This involves brain functioning and memory patterns." M. Clemens, "5th International Congress Psychosomatic," OB & GYN, Rome: Medical Tribune, Mar. 22, 1978, p. 7