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Multilingual Demographic Dictionary, second unified edition, English volume


Multilingual Demographic Dictionary, second unified edition, English vol.
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Viable  (VIABLE adj.)

A foetus is said to be non-viable 2 during the first part of a pregnancy and viable 1 thereafter. The change occurs when the foetus becomes capable of independent existence outside its mother, which is commonly considered to take place when the period of gestation 3 or duration of pregnancy 3 has exceeded 28 weeks. If the pregnancy has lasted longer than this, the expulsion of the foetus (alive or dead) takes place during confinement 4; an earlier explusion associated with an early foetal death is called an abortion 5 (cf. § 604). The period of about six weeks after delivery (during which the uterus usually regains its normal size and in which the probability of conception is low) is called the puerperium 6.

  • 1. Viable, adj. - viability, n.
  • 2. The minimum period determining viability varies between 20 and 28 weeks among countries, but the World Health Organization has recommended that 28 weeks be the standard time period. Generally the duration of pregnancy is computed from the onset of the last menses. This constitutes the conventional duration of pregnancy, as opposed to the true duration of pregnancy, computed from the time of conception.
  • 4. The actual process of expulsion of the foetus is called delivery or parturition, which is the termination of labor. In addition to those, confinement includes expulsion or removal of the placenta or afterbirth.
  • 5. Abortion, n. - abort, v.t. or v.i. - abortifacient, adj. used as n.: capable of inducing abortion. - abortionist, n.: a person who performs abortions. In everyday language, the term abortion often takes the meaning of induced abortion (604-2), as opposed to spontaneous abortion (604-1).
  • 6. Puerperium, n. - puerperal, adj. (cf. 424-4).