Obstetrical Nursing / A Text-Book on the Nursing Care of the Expectant Mother, the Woman in Labor, the Young Mother and Her Baby

by Carolyn Conant Van Blarcom

By the end of the fourth month, or sixteenth week, all parts show growth and development; lanugo appears over the body; the sex organs are clearly distinguishable and there is tarry fæcal matter, called meconium, in the intestines. The placenta is larger, the cord longer, more spiral and also thicker because of the Whartonian jelly which is beginning to form. The fetus is about 15 centimetres long and weighs about 120 grams.

By the end of the fifth month, or twentieth week, the fetus has both grown and developed markedly. It is now covered with skin on which are occasional patches of vernix caseosa, a greasy, cheesy substance consisting largely of a secretion of the sebaceous glands. There is some fat beneath the skin but the face looks old and wrinkled. Hair has appeared upon the head and the eyelids are opening. It is usually during the fifth month that the expectant mother first feels the fetal movements which are commonly referred to as “quickening.” The body is about 25 centimetres long and weighs about 280 grams.

By the end of the sixth month, or twenty-eighth week, the fetus still looks thin and scrawny, the skin is reddish and is well covered with vernix caseosa and the intestines contain an increased amount of meconium. If born at this time the child will move quite vigorously and cry feebly. Although it is not likely to live for any length of time, every effort should be made to save its life, for it may be that the high rate of mortality at this age is due to the inadequacy of the attempts which are usually made to save the child rather than to the frailty of the child itself. It is about 35 centimetres long and weighs about 1200 grams.

By the end of the eighth month, or thirty-second week, the child has grown to about 42 centimetres in length and 1900 grams in weight, but continues to look thin and old and wrinkled. The nails do not extend beyond the ends of the fingers but are firmer in texture; the lanugo begins to disappear from the face but the hair on the head is more abundant. If born at this stage, the baby will have a fair chance to live, if given painstaking care. This is true in spite of the ancient superstition, still widely current, that a seven months’ baby is more viable than one born at eight months (meaning calendar months). The fact is that after the eighth lunar month, a little more than seven calendar months, the probability of the child’s living increases rapidly with the length of its intra-uterine life.

By the end of the ninth month, or thirty-sixth week, the increased deposit of fat under the skin has given a plumper, rounder contour to the entire body; the aged look has passed and the chances for life have greatly increased. The baby now weighs about 2500 grams and is about 46 centimetres long.

The end of the tenth month, or fortieth week, usually marks the end of pregnancy. (Fig. [27].) The average, normally developed baby has attained a length of 50 centimetres (20 inches), and a weight of 3250 grams, or about 7¼ pounds, boys usually being about three ounces heavier than girls.

It must be remembered, however, that these figures merely represent the average drawn from a large number of cases, for there may be a variation in weight among entirely normal healthy babies from a minimum of 2300 grams (5 pounds) to as high as 5000 grams (11 pounds), or more. Babies actually weighing more than 12 pounds are seldom born, in spite of legends and rumors to the contrary.

The length of a normal baby is less variable than the weight. In fact, it is so nearly constant in its increase during the successive months of pregnancy, that the age of a prematurely born fetus may be fairly accurately estimated from its length. This fact is of no little practical importance, since it aids the obstetrician in making a prognosis as to the child’s prospect of living, for he can estimate its intra-uterine age from its body length.

The size of the baby is affected by race, colored babies, for example, averaging a smaller weight than white babies. And, as might be expected, the size of the parents is likely to be reflected in the size of their infants, large parents tending to have large children and vice versa.

The number of children which the mother has previously borne is also a factor, since the first child is usually the smallest, the size of those following showing an increase with the mother’s age up to her twenty-eighth or thirtieth year, provided the successive pregnancies do not occur at too frequent intervals.