Previable Fetal and Placental Development

  • Dagmar K. Kalousek
  • Naomi Fitch
  • Barbara A. Paradice


No formal system of staging exists for the fetal period. Development during the whole fetal period (9 weeks to term) primarily concerns rapid body growth and further differentiation of organs and tissues. There are no dramatic changes in the external appearance and, therefore, greater emphasis is placed on crown-rump (CR) and crown-heel (CH) measurements to establish fetal developmental age (see Appendix II, Table II-2). The fetal period can be subdivided into the previable fetal period (9 to 18 weeks of development) and the viable fetal period (19 to 38 weeks of development). Between the 9th and the 18th week, the rate of body growth is very rapid. The CR length of the fetus increases from 30 to 180 mm. The weight of the previable fetus varies and is unreliable as an indicator of developmental age (Golbus and Berry, 1977).


Umbilical Cord External Genitalia Fetal Period Placental Development Normal Fetus 


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  1. Golbus MS, Berry LC Jr: Human fetal development between 90 and 170 days post menses. Teratology 15: 103–108, 1977.PubMedCrossRefGoogle Scholar
  2. Hamilton WI, Boyd JD, Mossman MW: Human Embryology, ed 4, Fetus, Plenum Press, New York, London, pp 521–570, 1986.Google Scholar
  3. Moore KL: The Developing Human. Clinically Oriented Embryology, ed 3, Philadelphia, Saunders Co, 1982Google Scholar
  4. Nicolaides KM, Campbell S: Diagnosis of Fetal Abnormalities by Ultrasound. ed 2, Milunsky A (ed): Genetic Disorders and the Baltimore, MD, Williams & Wilkins Co, 1978.Google Scholar

Copyright information

© Springer Science+Business Media New York 1990

Authors and Affiliations

  • Dagmar K. Kalousek
    • 1
  • Naomi Fitch
    • 2
  • Barbara A. Paradice
    • 3
  1. 1.Department of PathologyThe University of British Columbia and BC Children’s HospitalVancouverCanada
  2. 2.Department of Pathology, Lady Davis Institute, Sir Mortimer B. Davis Jewish General HospitalThe University of British ColumbiaMontrealCanada
  3. 3.Embryopathology UnitBC Children’s HospitalVancouverCanada

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