Developmental facts references

Here are the scientific references for the developmental facts used on our election leaflet:

• The heart starts beating at 3 weeks and 1 day[1]

• Brain waves have been recorded as early as 6 weeks[2]

• The embryo begins to make spontaneous and reflexive movements,[3] and hand motions can be observed[4]

• Since week 8, the embryo has possessed more than 90% of the structures found in the adult body[5]

• By week 10, fingernails, toenails and unique fingerprints all appear[6]

• The fetus now yawns and opens and closes its mouth[7]

[1] Campbell S. 2004. Watch me grow: A unique 3-dimensional week-by-week look at your baby’s behavior and development in the womb. New York: St. Martins. 14; Carlson BM. 2004. Human embryology & developmental biology. 3rd ed. Philadelphia: Mosby. 430; de Vries PA, Saunders JB. 1962. Development of the ventricles and spiral outflow tract in the human heart. Carnegie Institution of Washington. Contrib Embryol. 37:87-114. 96; Gardner E, O'Rahilly R. 1976. The nerve supply and conducting system of the human heart at the end of the embryonic period proper. J Anat. 121(3):571-587. 583; Gilbert-Barness E, Debich-Spicer D. 1997. Cardiovascular system. In: Gilbert-Barness, editor. Potter's pathology of the fetus and infant. Vol 1. St. Louis: Mosby. 650; Gittenger-de Groot AC, Bartelings MM, Poelmann RE. 2000. Normal and abnormal cardiac development. In: Allan L, Hornberger LK, Sharland G, editors. Textbook of fetal cardiology. London: Greenwich Medical Media Limited. 15-27. 17; van Heeswijk M, Nijhuis JG, Hollanders HMG. 1990. Fetal heart rate in early pregnancy. Early Hum Dev. 22(3):151-156. 151; Kurjak A, Chervenak FA, editors. 1994. The fetus as a patient. New York: Parthenon. 439; Navaratnam V. 1991. Organisation and reorganisation of blood vessels in embryonic development. Eye. 5(Pt 2):147-150. 147-148; O'Rahilly R, Müller F. 1987. Developmental stages in human embryos. Washington: Carnegie Institution. 99; Wisser J, Dirschedl P. 1994. Embryonic heart rate in dated human embryos. Early Hum Dev. 37:107-115. 108.

[2] Borkowski WJ, Bernstine RL. 1955. Electroencephalography of the fetus. Neurology. 5(5):362-365. 363 (cited by Bernstine RL. 1961. Fetal electrocardiography and electroencephalography. Springfield: Charles C. Thomas. 63,66; O'Rahilly R, Müller F. 1999. The embryonic human brain: an atlas of developmental stages. 2nd ed. New York: Wiley-Liss. 195; van Dongen LGR, Goudie EG. 1980. Fetal movement patterns in the first trimester of pregnancy. Br J Obstet Gynaecol. 87(3):191-193. 193); Hamlin H. 1964. Life or death by EEG. JAMA. 90(2):112-114. 113. For a summary of in utero fetal encephalography (measuring brainwaves) in the near-term fetus using abdominal and vaginal electrodes see Bernstine RL, Borkowski WJ, Price AH. 1955. Prenatal fetal electroencephalography. Am J Obstet Gynecol. 70(3):623-630.

[3] Birnholz JC, Stephens JC, Faria M. 1978. Fetal movement patterns: a possible means of defining neurologic developmental milestones in utero. Am J Roentgenol. 130(3):537-540. 539; de Vries JIP, Visser GHA, Prechtl HFR. 1982. The emergence of fetal behaviour. I. Qualitative aspects. Early Hum Dev. 7(4):301-322. 301,304: “The first movements were observed at 7.5 weeks postmenstrual age.” [or 5½ weeks postfertilization age]; Humphrey T. 1964. Growth and maturation of the brain - some correlations between the appearance of human fetal reflexes and the development of the nervous system. In: Dominick P, Purpura DP, Schadé JP, editors. Progress in brain research. Vol 4. Amsterdam: Elsevier. 93-135. 99: earliest reflex 5½ weeks; Humphrey T. 1970. The development of human fetal activity and its relation to postnatal behavior. Advances in child development and behavior. Vol 5. Reese HW, Lipsitt LP, editors. New York: Academic. 12; Humphrey T, Hooker D. 1959. Double simultaneous stimulation of human fetuses and the anatomical patterns underlying the reflexes elicited. J Comp Neurol. 112:75-102. 76; Humphrey T, Hooker D. 1961. Reflexes elicited by stimulating perineal and adjacent areas of human fetuses. Trans Am Neurol Assoc. 86:147-152. 147; Kurjak A, Chervenak FA, editors. 1994. The fetus as a patient. New York: Parthenon. 48; Visser GH, Mulder EJ, Prechtl HF. 1992. Studies on developmental neurology in the human fetus. Dev Pharmacol Ther. 18(3-4):175-183. 175-176: “Endogenously generated fetal movements can first be observed after 7 weeks postmenstrual age (i.e. 5 weeks after conception)”; O'Rahilly R, Müller F. 1999. The embryonic human brain: an atlas of developmental stages. 2nd ed. New York: Wiley-Liss. 336: 5½ weeks postfertilization; Sorokin Y, Dierker LJ. 1982. Fetal movement. Clin Obstet Gynecol. 25(4):719-734. 723,726; Natsuyama E. 1991. In utero behavior of human embryos at the spinal-cord stage of development. Biol Neonate. 60(Suppl 1):11-29. 13: spontaneous movement observed by “Carnegie stage 15” (about 33 days postfertilization); Hogg ID. 1941. Sensory nerves and associated structures in the skin of human fetuses of 8 to 14 weeks of menstrual age correlated with functional capability. J Comp Neur. 75:371-410. 373: reflex activity begins at 6½ weeks [adjusted to postfertilization age].

[4] Endoscopic scans in “The Biology of Prenatal Development,” Endowment for Human Development, 2006

[5] O'Rahilly R, Müller F. 2001. Human embryology and teratology. 3rd ed. New York: Wiley-Liss. 87: “It has been estimated that more than 90% of the more than 4500 named structures of the adult body become apparent during the embryonic period (O'Rahilly).”

[6] O'Rahilly R, Müller F. 2001. Human embryology and teratology. 3rd ed. New York: Wiley-Liss. 170-171; Babler WJ. 1991. Embryologic development of epidermal ridges and their configurations. In: Plato CC, Garruto RM, Schaumann BA, editors. Dermatoglyphics: science in transition. New York: Wiley-Liss. 95-112. 95; Penrose LS, Ohara PT. 1973. The development of epidermal ridges. J Med Genet. 10(3):201-208. 201. For an overview of ridge formation in the skin of the hands see Cummins H. 1929. The topographic history of the volar pads (walking pads; tasballen) in the human embryo. Carnegie Institution of Washington. Contrib Embryol. 20:103-126.

[7] de Vries JIP, Visser GHA, Prechtl HFR. 1982. The emergence of fetal behaviour. I. Qualitative aspects. Early Hum Dev. 7(4):301-322. 309.