Books: The Prospective Mother
J >>
J. Morris Slemons >> The Prospective Mother
Pages:
1 |
2 |
3 | 4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
17 |
18 |
19 |
20 |
21
So far as is known; the umbilical cord performs no service other than
to link the blood-vessels in the placenta with those in the fetus.
Simple as this may seem, it is of paramount importance in maintaining
the life of the fetus, for compression of the vessels in the cord
would shut off its nutriment. Against such accident, however, perfect
provisions have been made; both the amniotic fluid and the jelly-like
substance which surrounds the vessels are safeguards which
effectually protect the circulation from pressure that might
interrupt it.
Frequently, prospective mothers are told they must not "reach up" for
fear the cord will become entangled. Such a precaution is quite
unnecessary. No matter what the mother does, or does not, the cord
will be found around the child's neck at the time of birth in one of
every three cases. It is not difficult to understand how this
happens. The cord is longer than the uterine cavity and must fall in
coils toward the bottom of it. Now, since the fetus is free to move
it enters and withdraws from these loops, many times, in the course
of pregnancy. Finally, when it takes up a position head downward, as
it nearly always does, the head is the part of the fetus which passes
through the coil, should one happen to lie in its path. After the
head is delivered the physician always feels about the neck to
discover whether a loop of cord is there. If it is, he can release it
easily. This condition, since it occurs so frequently and since it so
rarely produces harmful consequences, should not be considered
unnatural.
After the child is born, the physician cuts the cord, and in due time
the after-birth is expelled through the same passage as was the
child. The expulsion of the after-birth frees the mother of all the
tissue derived from the growth of the ovum, for the intricate
mechanism that served to nourish and protect the embryo was almost
entirely developed from the ovum itself. It is a remarkable provision
of Nature that very little of the mother's tissue is cast off at the
end of pregnancy; and even this small portion is promptly replaced.
By about the sixth week after delivery, the wound which was made by
the separation of the fetal sac has completely healed. Meanwhile the
mucous membrane that underwent elaborate preparations to receive the
ovum, the cavity that was adjusted to its growth, and the muscle
fibers that were strengthened to insure its safe entry into the world
have all regained their original state. Except for the activity of
the breasts, the mother is left in the same physical condition as
before she became pregnant.
CHAPTER III
THE EMBRYO
The Development of Form--The Determination of Sex--Twins--The Rate
of Growth--The Newborn Infant--Heredity--Maternal Impressions.
The new human being begins existence, as I have shown, as soon as the
ovum is fertilized, though at that moment it consists merely of a
solitary cell formed by the union of the two parental cells. From a
beginning relatively simple the human body develops into the most
complex of living structures; and, startling as it may appear to be,
it is demonstrably true that every one of the millions of cells which
compose an adult has descended from the ovum. Furthermore, the
individual himself is not the entire progeny of the ovum; the
placenta and the membranes dealt with in the preceding chapter, we
saw, were also derived from that same source. They possess only a
transitory importance, to be sure, and to most persons they are less
interesting than the embryo, yet we gave them consideration before
discussing its growth because the manner in which the ovum becomes
attached to the womb and draws nutriment from the mother primarily
determines the fate of a pregnancy.
Now that we have become familiar with the arrangements for the
protection of the embryo, we are prepared to learn how it develops,
and may accept the phrase, embryonic development, to cover the whole
period of existence within the womb. In a more technical sense,
however, the use of the term _embryo_ is limited to the first
six weeks of pregnancy and designates the condition of the young
creature before it has acquired the form and the organs of the
infant; after that time the unborn child is called a _fetus_.
Embryonic development, therefore, in the strictest sense of the term,
chiefly involves the shifting of various groups of cells and the
bestowal upon them of different kinds of activity. During this period
comparatively slight growth takes place. By about the twentieth week,
the house, it may be said, is set in order; and there follows a
period marked by the rapid growth of the fetus.
THE DEVELOPMENT OF FORM.--A very old explanation of embryonic
development was that the process consisted altogether in growth.
According to that view the embryo lay curled up in the egg; at the
outset it was equipped with organs, limbs, features, and all the
other bodily structures found in an adult. In order that the ovum
might be transformed into a mature infant, only unfolding and growth
were required. After the microscope came into use, however, so simple
an explanation could no longer be accepted. Scientists soon realized
that the embryo did not exist "ready made" in the ovum, which, even
when magnified, failed to bear the faintest likeness to a human
being.
Although the microscope made impossible this very simple explanation,
it gave in return a truer, if more complex, account of the
transformation from egg to offspring. By this means it has been
definitely proved that the ovum multiplies rapidly after it has been
fertilized, and becomes, as was explained in the preceding chapter, a
sac-like structure within which hangs a tiny clump of tissue. This
inner mass of cells forms the embryo.
It has proved a difficult task to secure very young human embryos,
and many of the ideas we hold relative to the initial stages in the
development of man are based upon what has been found true in certain
mammals, the class of animals to which we belong. The youngest human
ovum known at present has already undergone about two weeks'
development, and there the embryo is represented by a flat disk. From
this stage to the stage of complete development a satisfactory series
of embryos has now been collected, but it is impossible to give here,
even in outline, a description of the evolution of the human embryo.
No one can understand this intricate subject without the aid of
diagrams, models, and other material beyond the reach of all save
laboratory workers.
By the end of the second month the development of the embryo has
advanced so far that anyone could recognize its human shape. About
that time, too, the external sexual organs make their appearance. At
first these are quite similar in both sexes; and, if they are used as
the criterion, it is possible only toward the end of the third month
to say whether the embryo is a male or female.
THE DETERMINATION OF SEX.--The fact that a number of months pass
before the sex can be distinguished by an external examination of the
fetus has led to the erroneous belief that it can be influenced
during the early part of pregnancy or actually determined at will.
Various means to accomplish this have been suggested; many of them
depend upon modifying the mother's mode of living according as a boy
or girl is desired. The most widely known of these doctrines, that of
Schenck, was to the effect that the sex of the offspring is always
that of the weaker parent. He suggested, therefore, that increasing
the vigor of the mother by an appropriate diet would produce a male
child, whereas a decrease in her strength would lead to the opposite
result. His views, however, were incorrect. After studying extensive
statistics Newcomb came to the conclusion that "it is in the highest
degree unlikely that there is any way by which a parent can affect
the sex of his or her offspring."
Moreover, the results of experimental research clearly indicate that
we shall never possess the means by which a mother may control the
sex of her child. In the main laboratory investigations have sought
to answer two questions. First, at what time is the sex of the
offspring determined? and, second, what accounts for the origin of a
male in one instance and of a female in another? The study of these
problems has been carried on chiefly in connection with insects,
worms, and fowl; but as yet insurmountable difficulties have
prevented similar investigations in higher animals. For this reason,
it is not without the greatest caution that results thus far obtained
may be assumed to apply to man.
Sufficient facts, however, have been collected to admit no doubt
regarding the answer to the first question. In most animals it is
definitely known that the sex of the offspring has been fixed when
the male cell enters the female cell, in other words, at the instant
the ovum is fertilized. Excellent reasons exist for believing that
human beings conform to this rule, and that the sex of the child is
unalterably determined at the moment conception occurs. Consequently,
any attempt to influence it after that event must prove futile.
For the present, the second question cannot be answered with equal
assurance. More than five hundred theories have been offered to
explain the relation of sex; nearly all of them have no reasonable
foundation and are only of historical interest. The view that girls
are derived from the right ovary, boys from the left, has long since
been disproven, and deserves mention merely because the laity still
believe it. Happily, during the last few years, observations and
experiments have been made which greatly advance our knowledge of the
subject and give promise of an early solution of the problem. The
controlling factor in sex determination has been narrowed down to
three possibilities; it is inherited either from the single cell
contributed by the father or from the single cell contributed by the
mother, or it is determined by the effect these two cells have upon
each other at the moment when they unite. In most animal species the
weight of authority distinctly favors placing the whole
responsibility upon the male cell.
According to recent evidence, there are two kinds of male germinal
cells; one kind giving rise to female offspring and the other to
male. In all probability, at the time of the marital relation, these
varieties are deposited in the vagina in equal numbers; and,
moreover, the mode of their production is such as to place absolutely
beyond human control the possibility of changing this ratio. Since
only one spermatozoon enters the ovum, whether or not the child will
be a boy or a girl depends entirely upon which type gains entrance.
If this explanation is correct, and it is in accord with careful
biological observations, it removes from the mother all
responsibility for the sex of her child. Furthermore, since the facts
indicate that male-producing and female-producing spermatozoa are
present in equal numbers, it follows that practically there is an
even chance that an embryo will develop into a boy or a girl.
Birth statistics bear out this conclusion, as data gathered from many
countries indicate that when long periods of time are studied 105
boys are born with a surprising regularity for every 100 girls. Thus,
the records of Berlin, Germany, for a hundred years show that the
maximum difference occurred in 1820, when the males outnumbered the
females by 4.79 per cent.; the minimum difference, which was noted in
1835, was .64 per cent. in favor of boys.
No inquiry is more often submitted to the physician by prospective
mothers than this, "Can you tell me if my baby will be a boy or a
girl?" He cannot. Many rules, to be sure, have been advocated as safe
guides toward reaching the correct answer; every midwife possesses
her individual formula which she has "never known to fail." But the
boastful success depends upon the application of some such method as
the following, which I have heard my teacher, Dr. J. Whitridge
Williams, expose to his classes. The patient is asked if a boy or
girl is desired. She confesses, and is then informed that the sex of
her child will be the opposite of her wish. When this guess proves to
be correct, there is no doubt of the prophet's wisdom; when it is
not, his honor is protected, for the parents have had their hope
fulfilled. Their happiness makes them forgetful that the guess was
wrong, or, for that matter, that it was ever made.
It was once believed that the sexes might be distinguished before
birth by the number of heart beats occurring within a minute. In a
general way, the action of this organ in females is somewhat more
rapid than in males; and so it was thought that a rate of 144 or more
indicated the female and a rate of 124 or less the male sex. But
experience has taught that this rule leads to accurate prophecy in no
more than half of the cases. As a matter of fact, no means of
definitely foretelling the sex of the child has been discovered, and
I doubt if it ever can be.
TWINS.--As every one knows, pregnancy commonly terminates with the
birth of a single child. Twins appear in approximately only one of
ninety pregnancies, while triplets are extremely rare. It is true
that even quintuplets may occur, though up to 1904 only 29 authentic
instances could be collected from the whole range of medical
literature.
Twins are most frequently born to parents whose ancestors have
established this tendency; the trait is usually inherited from the
mother's family, though occasionally it is passed on through the
father. Of course, that does not explain the cause of twins, which in
reality may result from either of two circumstances. More commonly
their genesis depends upon the ripening of two eggs at about the same
time and the fertilization of both by two different spermatozoa. The
children, in this instance known as double ovum twins, may be of the
same sex or not. On the other hand, single ovum, or identical, twins
are always of the same sex; this follows, since but one egg and but
one spermatozoon are here concerned. The incident permitting twins to
develop from a solitary ovum must occur soon after conception has
taken place. It will be remembered that the first step in the
development of the fertilized ovum consists in its dividing into two
cells. Ordinarily, both these take part in the development of one
embryo, but occasionally they separate and give rise to two.
Frequently, the presence of twins can be recognized during the latter
months of pregnancy, and accurate means are known of determining
after they are born to which variety any given pair belongs.
THE RATE OF GROWTH.--When we recall the definite and often marked
differences in the physical character of women, such as weight and
height, it is surprising to learn that the prenatal development of
their children proceeds with uniform speed. One very practical result
is that the physician is thus enabled, at the birth of a premature
infant, to estimate accurately the period of its development. Various
criteria, some of which are easy of application, aid in this
determination. For example, the length of the child is practically
constant for each of the ten lunar months into which the whole
gestation period is divided; if, therefore, the length of the newborn
infant is known, the stage of its development can always be inferred.
From the fifth month the calculation is especially simple, since the
length measured in centimeters divided by the figure 5 gives the
month to which pregnancy has advanced. Similarly, we can infer the
period of development from the weight, though the calculation is more
intricate and the method less reliable, inasmuch as the size of the
child in the latter months varies somewhat according to the weight of
its mother.
At the end of the fifth month, the weight of the fetus is from nine
to ten ounces; whereas an average infant when born at the expiration
of the full term of pregnancy, that is, with the completion of the
tenth month, weighs about seven pounds. The fetus, therefore,
acquires roundly ninety per cent, of its weight during the second
half of pregnancy, which clearly indicates that Nature reserves this
period of gestation for the fetus to increase in size, a phenomenon
less mysterious but no less important than the evolution of the
embryo.
Nothing is more valuable than the weight in affording an indication
as to whether a prematurely born infant may be reared. It is unusual
to raise a child weighing less than four pounds, which corresponds
approximately to the end of the eighth lunar month of development (a
trifle more than the seventh calendar month). After this time, the
prospect of living becomes greater in proportion to the nearness with
which the infant has approached maturity. No truth exists in the
widespread belief that the seventh-month child is favored above that
born later but before the natural end of pregnancy. Experience has
taught that the probability of success in rearing the child increases
rapidly after the seventh month. This is reasonable on the following
somewhat theoretical grounds. The digestive organs later attain a
higher state of perfection, and are better prepared to carry on their
work satisfactorily. Moreover, the gradual deposition of fat beneath
the skin during the last two months of pregnancy materially assists
in fitting the child for the conditions met with in the external
world, since the fat affords a barrier against the escape of heat
generated within the body, making it much easier to keep the child's
temperature at the normal point. Even other more technical reasons
could be given to demonstrate the error of the superstition regarding
the seventh-month child--a conviction endorsed by medical men
hundreds of years ago and as yet not discarded by the laity.
When pregnancy has reached "term," the child, having completed its
prenatal development, is ready to cope with conditions as they exist
in the external world. At term the average child is twenty inches
long and weighs 7 1/7 pounds (3,250 grams). The length is remarkably
constant; but the weight, as is well known, is often somewhat above
or below the average figure. In a general way, smaller children occur
in the first than in subsequent pregnancies, and, moreover, may be
expected when the mother is a small woman, or poorly nourished, or
has worked hard during her pregnancy. On the other hand, a tendency
to bear large children is present when the opposite conditions
prevail. It is not unusual to see infants weighing eight or nine
pounds at birth, but babies of more than ten pounds are rare, and the
fabulous, though not infrequent, reports of fifteen and twenty-pound
infants are probably not based upon actual weighings, but upon the
impression of someone who has merely seen the child or perhaps
guessed the weight from lifting it.
Although the fetus frequently changes its position during the earlier
months of pregnancy, generally by the beginning of the tenth lunar
month it has assumed a permanent posture. It has then reached such a
size that it can best be accommodated in the cavity of the uterus if
its various parts are folded together so as to give the fetus an
ovoid shape. To secure this form its back is arched forward, and its
head bent so that its chin touches its chest; its arms are crossed
just below the head, its legs raised in front of the abdomen, and its
knees doubled up. In this form the fetus occupies the smallest
possible space.
With relation to the mother the position of the child, for several
weeks before birth, is one in which its long axis is parallel to the
long axis of her body. This remains true no matter whether the head
or the buttocks are to precede at the time of birth. In ninety-seven
out of a hundred cases, however, the head lies lowermost and
consequently is the first portion of the child to be born. The
opposite position, in which the head is the last portion born, is,
even with the most skillful treatment, somewhat more serious for the
infant, though not for the mother.
THE NEWBORN INFANT.--The baby at birth is not a miniature man. As
compared with an adult its head and abdomen are relatively large, its
chest relatively small; its limbs are short in proportion to the
body; and at first glance it appears to have no neck at all. The
middle point of a baby's length is situated about the level of the
navel, whereas in a man the legs alone represent approximately half
his height. The changes after birth consist chiefly in growth; but
not altogether, since at least one organ, the thymus gland, becomes
smaller and completely disappears during childhood, and other organs,
especially the liver, are proportionately smaller in the adult than
in the infant.
The body of the infant also differs from that of the man in
possessing greater softness and flexibility. These qualities depend
upon the nature of its skeleton, which is composed of more bones than
later in life, when several have fused together to form one to give
the mature body a more rigid frame. Furthermore, the individual bones
are not so firm, consisting of an elastic material called cartilage,
so that some movements which in an adult would cause such serious
injuries as fractures and dislocations are perfectly harmless to a
newborn child.
The legs are not only short in proportion to the body but are always
curved, and the feet are held with the soles directed toward one
another, a position clearly abnormal in the adult. But every mother
should know that these are natural conditions in the infant, and are
the result of the posture of the child before birth. They soon
straighten out. The bowed legs of an adult are of an entirely
different origin, resulting from a disturbance of nutrition in
infancy called rickets.
A small amount of short wooly hair is usually found over the back of
a newborn infant. More conspicuous, however, is the presence there of
a gray, fatty substance which, though always more abundant over the
back, is at times distributed over the whole body; rarely is it
entirely absent. The material, technically named the vernix, is the
product of the glands in the skin and is a perfectly normal
secretion. After its removal, which is readily accomplished by
greasing the infant with lard or vaselin before giving the initial
bath, it never reappears.
A varying amount of hair covers the head of the infant. No
significance should be attached to the quantity, for the conviction
that exists, especially among negroes, that a heavy suit of hair for
the child occasions "heart-burn" in the mother during pregnancy is
without foundation. The color of the hair at birth does not indicate
its ultimate shade; changes are often noted during infancy. Similarly
the permanent color of the eyes is not assumed until later; at the
time of birth the eyes are generally, if not always, blue in color.
A baby's head is a matter of great concern to the family.
Occasionally, the skull is round and well shaped from the moment of
birth, but more often it is long and narrow; sometimes the form is
even startling to the inexperienced. The peculiar shape of the head
results, of course, from its passage through the birth-canal and is
not a sign of any disease. In a few weeks, or even less, the strange
appearance passes away. It is unwise to attempt to alter the shape of
the head by bandaging or massaging since the growth of the brain will
spontaneously accomplish what is desired; interference can do no
good, and may do serious harm.
Nature facilitates an appropriate molding of the head during birth so
as to permit its easy passage through the bony pelvic cavity of the
mother, and gains that end in two ways. The bones of the head remain
pliable until after the infant is born, and, further, their edges are
not welded together as in an adult, but are separated from one
another by an appreciable distance. During the act of birth the edges
are brought into contact or even overlap, materially reducing the
size of the head. Within a few hours after birth the bones again
spread apart, and some months elapse before they begin to unite; the
union is not completed until some time during the second year of
infancy.
Many mothers are anxious to know how far the senses of the infant
have developed when it enters the world. This problem has stimulated
some scientific investigation, though hardly so much as its interest
would justify. Two lines of inquiry have been pursued toward its
solution. The objective point of one of these has been to determine
how nearly the sense organs of the newborn correspond anatomically to
those of an adult; that is how perfectly has their organization been
completed. The other has been to learn how the infant reacts when the
various senses are stimulated; the interpretation of these reactions
is, however, particularly liable to error and sometimes amounts only
to guesswork.
The organization of the nerves and muscles in the eye is far from
perfect at the time of birth. The muscles act irregularly; indeed,
the lack of muscular adjustment is such that movements of the eye
likely to alarm the parents are regularly observed in very young
infants. Furthermore they cannot focus images which fall upon their
eyes. The retina, which receives visual impressions, has reached such
development at birth, however, that sensations of light can be
perceived. For example, if a lamp is suddenly flashed before the face
of a newly born baby it cries. From this and similar evidence,
indicating that strong light irritates the delicate structures of the
eye, we have learned that a nursery should not be illuminated, during
the day or night, so brightly as the rooms adults occupy. Certainly
several weeks, and probably several months, pass before an infant can
see anything save as blurs of light and darkness. Objects, such as a
hand, probably appear as shadows, which are not correctly interpreted
until late in infancy.
Pages:
1 |
2 |
3 | 4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
13 |
14 |
15 |
16 |
17 |
18 |
19 |
20 |
21