. A treatise on obstetrics for students and practitioners . cm. = ll/9 inches. At the end of 6 months 6 X 5 = 30 cm. = 13V3 inches. At the end of 7 months 7 X 5 = 35 cm. = 155/9 inches. At the end of 8 months 8 X 5 = 40 cm. = 177/9 inches. At the end of 9 months . . . 9 X 5 = 45 cm. = 20 inches. At the end of 10 months 10 X 5 = 50 cm. = 222/9 inches. To obtain the length of the foetus, multiply the month of preg-nancy (first, second, etc.) by a coefficient—one for the first month, twofor the second, etc., up to five. After the fifth month the coefficient 78 PREGNANCY AND LABOR. remains five. T
. A treatise on obstetrics for students and practitioners . cm. = ll/9 inches. At the end of 6 months 6 X 5 = 30 cm. = 13V3 inches. At the end of 7 months 7 X 5 = 35 cm. = 155/9 inches. At the end of 8 months 8 X 5 = 40 cm. = 177/9 inches. At the end of 9 months . . . 9 X 5 = 45 cm. = 20 inches. At the end of 10 months 10 X 5 = 50 cm. = 222/9 inches. To obtain the length of the foetus, multiply the month of preg-nancy (first, second, etc.) by a coefficient—one for the first month, twofor the second, etc., up to five. After the fifth month the coefficient 78 PREGNANCY AND LABOR. remains five. Thus, at the seventh month the foetus is 7 x 5 centi-metres long, 35 cm., or 15 inches. An indication as to the comparative development of the foetus isoften sought in the size of the placenta aud the length of the statement is as follows : Month. No. of observations. Placenta. Cord. Third 3 36 grammes. 7 cms. 17 80 ■ 19 Fifth 24 178 31 Sixth 14 273 37 Seventh 19 374 42 Eighth 32 451 46 Ninth . . 45 461 47 Tenth 62 481 51 Fig. Embryo of four weeks. (His.)1. Cervical spine. 2. Gills (aural opening). 3. Mouth-fissure. 4. Chorion and villi. 5. Amnion. The weight of the foetus at various periods of gestatiou variesgreatly. The factors which have to do with the size of the foetus aremany, and are not accurately known. Besides the general factors THE GROWTH AND DEVELOPMENT OF THE EMBRYO. 79 which influence nutrition, such as abundance of food or deprivation,exhausting labor, or rest and freedom from mental anxiety, the pro-longation or the interruption of gestation probably influences the size andweight of the foetus more than any other known factor. It is naturalto expect that very young mothers, bearing children prematurely, asthey do, should have small children, while children born of mothersat the period of greatest maturity and development, between thirty and
Size: 1423px × 1757px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectobstetrics, bookyear1
