Accuracy
Calculations of gestational age from LMP are sometimes incorrect due to normal variation from the average ovulation date. The gestational age of an individual infant can be more accurately estimated from:
- The woman's knowledge of the date of sexual intercourse.
- The woman's knowledge of fertility signs related to ovulation. The needed observations are normally made by women who use fertility awareness methods to get pregnant.
- Examination of the newborn infant. In the twentieth century, doctors (especially pediatricians) were trained to recognize the physical changes occurring to the fetus in the latter half of pregnancy so that a maturational age could be estimated.
- An obstetric ultrasound ("dating scan", in the UK routinely offered around 12 weeks) during the pregnancy, whereby sizes of certain fetal body parts are measured.
The fertilization age of children conceived by in vitro fertilization is known to the hour.
Read more about this topic: Gestational Age
Famous quotes containing the word accuracy:
“The child who has been taught to make an accurate elevation, plan, and section of a pint pot has had an admirable training in accuracy of eye and hand.”
—Thomas Henry Huxley (1825–95)
“In everything from athletic ability to popularity to looks, brains, and clothes, children rank themselves against others. At this age [7 and 8], children can tell you with amazing accuracy who has the coolest clothes, who tells the biggest lies, who is the best reader, who runs the fastest, and who is the most popular boy in the third grade.”
—Stanley I. Greenspan (20th century)
“U.S. international and security policy ... has as its primary goal the preservation of what we might call “the Fifth Freedom,” understood crudely but with a fair degree of accuracy as the freedom to rob, to exploit and to dominate, to undertake any course of action to ensure that existing privilege is protected and advanced.”
—Noam Chomsky (b. 1928)