TY - CHAP M1 - Book, Section TI - The Passenger: Fetus A1 - Posner, Glenn D. A2 - Posner, Glenn D. A2 - Dy, Jessica A2 - Black, Amanda A2 - Jones, Griffith D. Y1 - 2015 N1 - T2 - Oxorn-Foote Human Labor & Birth, 6e AB - Resemblance to the adult human form may be perceptible at the end of 8 weeks and is obvious at the end of 12 weeksBy the end of 12 weeks and sometimes sooner, the sexual differences in the external genitalia may be recognized in abortusesGrowth is greatest during the sixth and seventh months of intrauterine lifeQuickening (the perception by the pregnant woman of fetal movements in utero) occurs between the 16th and 20th weeks of pregnancy. The time of quickening is too variable to be of value in determining the expected date of confinement or when term has been reached. Active intestinal peristalsis is the most common phenomenon mistaken for quickeningDepending on maternal body habitus, the fetal heart is audible using a fetal Doppler by the 12th to 13th weeks of gestationThe fetal heart is audible using a stethoscope by the 18th or 20th weekThe average length of the fetus at term is 50 cmWithin wide variations, the average boy in Canada (7 pounds, 15 oz or ~3600 g) is a little heavier at birth (based on 40 weeks gestational age) than the average girl (7 pounds, 10 oz or ~3500 g)In premature babies, the circumference of the head is relatively large compared with the shoulders. This fact is of clinical relevance when contemplating preterm breech delivery. As the fetus matures, the body grows faster than the head, so that at term, the circumferences of the head and the shoulders are nearly the same SN - PB - McGraw-Hill Medical CY - New York, NY Y2 - 2024/04/19 UR - obgyn.mhmedical.com/content.aspx?aid=1106375655 ER -