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THE PROSPECTIVE MOTHER
A Handbook for Women During Pregnancy
by
J. MORRIS SLEMONS
Associate Professor of Obstetrics,
The Johns Hopkins University.
* * * * *
PREFACE
This book, written for women who have no special knowledge of
medicine, aims to answer the questions which occur to them in the
course of pregnancy. Directions for safeguarding their health have
been given in detail, and emphasis has been placed upon such measures
as may serve to prevent serious complications. Treatment of such
conditions has not been discussed, as it can be judiciously carried
out only by a physician who has the opportunity to observe and study
the individual patient. Furthermore, if there is to be notable
improvement in the management of cases of childbirth, the appearance
of untoward symptoms should not be awaited before consulting a
physician; on the contrary, prospective mothers must be taught that
they should be under competent medical supervision throughout
pregnancy.
At present intelligent women demand some knowledge of the anatomical
and physiological changes incident to the development of the embryo
and the birth of the child. These subjects do not readily lend
themselves to popular description, but I have told the story as
simply as possible, following in a general way the text-book of my
teacher and friend, Professor J. Whitridge Williams; indeed, my main
purpose has been to reproduce his book "in words of one syllable."
The use of a number of technical words has been unavoidable, and,
though their meaning has been given in the context, it has not been
feasible to repeat the definition every time an unfamiliar term was
used. On that account a glossary has been provided.
It is with pleasure that I avail myself of this opportunity to
acknowledge the cheerfully given assistance of many friends. In
particular I wish to thank Doctor Henry M. Hurd, until recently
Superintendent of the Johns Hopkins Hospital, for his interest and
advice. I am also under deep obligation to my friend John C. French,
of the English Department of the Johns Hopkins University, for
helpful criticism of the manuscript, and to my colleagues, Doctors
Rupert Norton and Thomas R. Boggs, for valuable assistance. To many
others--doctors, nurses, and patients--I am indebted for numerous
suggestions which have been made either consciously or unconsciously.
J. MORRIS SLEMONS.
* * * * *
INTRODUCTION
In all branches of medicine the master word is _prophylaxis_, or
prevention, and its benefits are nowhere more strikingly illustrated
than in the practice of obstetrics. In former times every woman who
gave birth to a child or passed through a miscarriage was exposed to
grave danger of infection or child-bed fever; but at present--thanks
to the recognition of the bacterial origin of the disease and of its
identity with wound infection--this danger can be practically
eliminated by the rigid observance of surgical cleanliness and
aseptic technique. Physicians have also learned that the most
effective method of coping with other serious complications of
pregnancy and labor is by preventing their occurrence, or at least by
subjecting them to treatment in their earliest stages; for, if they
be allowed to go on to full development, the results are little
better than in times past. Furthermore, a careful examination some
weeks before the expected date of confinement enables us to recognize
the existence of abnormal presentations and of disproportion between
the size of the mother's pelvis and that of the child's head. Timely
recognition of such conditions makes appropriate treatment possible
and practically insures a successful outcome; while tardy recognition
is frequently followed by disastrous results.
These few examples give some idea of the benefits of prophylaxis in
the practice of obstetrics. Prospective mothers should understand not
only that there is an advantage in taking such precautions, but that
they may be risking their lives, or at least their future well-being,
unless they insist upon competent medical attention. It is true, of
course, that pregnancy and childbirth are generally normal processes,
but they are not always so. Fortunately, most of the abnormalities
give timely warning of their occurrence, and in most instances may be
relieved by comparatively simple measures; or, if not, they afford
indications for treatment which should lead to a happy termination.
The recognition of the existence of such conditions, however, is not
always easy, and their ideal treatment requires careful training and
sometimes the utmost nicety of judgment. Consequently, if prospective
mothers wish to be assured of the best care, they should be cautious
in the choice of their medical attendant. As the ordinary layman has
no means of determining the real qualifications of a physician, the
choice should not be made upon the advice of casual acquaintances;
but, instead, the family physician should be consulted, who, should
he feel unwilling to assume the responsibility of the case, will be
able to recommend a thoroughly competent substitute.
From my own experience as a teacher and consultant, I state without
hesitation that in no other branch of medicine or surgery are graver
emergencies encountered than in certain obstetrical complications
whose treatment involves the greatest responsibility and requires the
highest order of ability to insure a successful outcome for the
mother and her child. For these reasons a physician should be chosen
only after mature deliberation, and his services should be esteemed
much more highly than is usually the case.
In order that the principles of prevention may receive their fullest
application during pregnancy, labor, and the lying-in period, it is
also advisable that intelligent women should possess some knowledge
of the Reproductive Process in human beings. This information is
imparted by Doctor Slemons' book, which I can thoroughly recommend to
prospective mothers. The subject matter has been carefully chosen,
and the author has wisely refrained from giving advice with regard to
treatment which can be satisfactorily directed only after careful
study by a physician. At the same time he has given a clear account
of the physiology of pregnancy and labor, and has laid down sound
rules for the guidance of the patient.
One of the most important facts emphasized by Doctor Slemons is the
value of medical supervision for several weeks after the child is
born; this precaution contributes greatly toward a rapid and complete
convalescence. During the lying-in period the physician should
supervise the care of the mother and the child, should insist upon
the necessity for maternal nursing, and should keep the mother under
observation until perfectly normal conditions are regained. If the
latter duty is conscientiously fulfilled many years of invalidism may
be saved and thousands of operations rendered unnecessary.
Although there have been notable advances in the science and in the
art of obstetrics since the middle of the eighteenth century, a great
many fundamental facts must yet be learned. For example, we are
almost totally ignorant of the stimulus which causes the mother to
fall into labor approximately 280 days after the last normal
menstruation.
There are two points which I desire to impress especially upon the
readers of this book. Firstly, that the advance of the science of
obstetrics, and consequently improvements in its practice, must
depend greatly upon the cooperation of intelligent women. They must
come to realize that they will secure the best treatment only as they
demand the highest standard of excellence from their attendants; and
they can aid in securing this for their poorer sisters and their
children by interesting themselves in obstetrical charities.
Secondly, they must realize that real progress in the science of
obstetrics can be expected to proceed only from well equipped clinics
connected with strong universities, and in charge of thoroughly
trained and broad-minded men. As yet such institutions scarcely exist
in this country. Women who are anxious to promote the welfare of
their sex can find no better way of doing so than by bringing this
need to the attention of wealthy men interested in philanthropy and
education. Furthermore, they should bear in mind that most of our
important discoveries would not have been made had animal
experimentation not been available, as it is solely by this means
that modern surgical and obstetrical technique has been brought to
its present degree of perfection; and further progress can scarcely
be expected without its aid. They should remember also that whenever
they take such a well-known drug as ergot for the control of
bleeding, or make use of many other apparently simple measures, they
are unconsciously rendering tribute to this type of investigation.
J. WHITRIDGE WILLIAMS.
Johns Hopkins University,
September, 1912.
* * * * *
CONTENTS
I. THE SIGNS OF PREGNANCY AND THE DATE OF CONFINEMENT
II. THE DEVELOPMENT OF THE OVUM
III. THE EMBRYO
IV. THE FOOD REQUIREMENTS DURING PREGNANCY
V. THE CARE OF THE BODY
VI. GENERAL HYGIENIC MEASURES
VII. THE AILMENTS OF PREGNANCY
VIII. MISCARRIAGE
IX. THE PREPARATIONS FOR CONFINEMENT
X. THE BIRTH OF THE CHILD
XI. THE LYING-IN PERIOD
XII. THE NURSING MOTHER
GLOSSARY
* * * * *
The Prospective Mother
CHAPTER I
THE SIGNS OF PREGNANCY AND THE DATE OF CONFINEMENT
The Positive Signs--The Probable Signs--The Presumptive Signs: The
Cessation of Menstruation; Changes in the Breasts; Morning Sickness;
Disturbances in Urination--The Duration of Pregnancy--The Estimation
of the Date of Confinement--Prolonged Pregnancy.
Many puzzling questions occur to the woman who is about to become a
mother. Most of these questions are reasonable and natural, and
should be frankly answered; but a false conventionality has--until
recently, at least--forbidden any open discussion of facts connected
with childbirth. The inevitable result has been that, without
experience of their own to guide them, prospective mothers have
sought advice from older women, whose experience was at best very
narrow, and whose views were often biased by tradition. Or,
distrusting such sources of information, they have consulted
technical medical works which they could not understand. Either of
these methods is very likely to result in misinformation and to cause
unnecessary anxiety. Yet no one need be alarmed by a plain, accurate
account of Nature's plan to provide successive generations of human
beings. Some trustworthy knowledge of a process so fundamental should
be part of every person's education; it is especially helpful to
women who are pregnant because it affords a rational basis for
hygienic measures which they should adopt. A popular work, however,
no matter how frank and helpful it may be, will not enable one to
dispense with professional advice. For the prospective mother no
counsel is more important than this: _Put yourself at once under
the care of a physician_.
Insistence on the importance of medical advice should not be taken to
imply that pregnancy is to be regarded as other than a normal
process. Its dangers are comparatively slight, as we should expect,
since the property of all living matter to reproduce its kind is both
fundamental and essential; the continuance of living creatures in
this world, plants as well as animals, depends upon the Reproductive
Process. And yet, natural as it is, pregnancy may be attended by
complications. Such complications, though happily rare, are to be
guarded against in every case, and that may be most effectually done
if patients are taught to remain under competent medical supervision
from the time of conception until several weeks after the child is
born. This precaution greatly reduces the frequency of annoyances
during pregnancy and also assists materially toward conducting a
birth to a safe conclusion. Moreover, if this advice is followed,
when complications do arise they will be recognized and dealt with
promptly; they will not be permitted to grow more serious until,
perhaps, they may jeopardize the life of the mother or the child or
both.
The initial symptoms of pregnancy are so widely known that in most
instances the prospective mother herself makes the diagnosis shortly
after conception has taken place; but now and then pregnancy advances
for several months unrecognized and is then detected by a physician
who has been consulted on account of symptoms which the patient has
incorrectly attributed to some other condition. On the other hand,
women sometimes suspect that they are pregnant when they are not; and
such mistakes occur because certain symptoms which are implicitly
trusted by the laity as manifestations of pregnancy are occasionally
associated with conditions quite foreign to it. It is clear that one
interested in the matter must know not only what the manifestations
of pregnancy are and when they appear, but also how far the evidence
that they give is reliable.
The signs of pregnancy may be classified, according to their
reliability, as presumptive, probable, and positive. The doubtful
evidence appears first and the infallible proof last. No one need be
surprised, therefore, if, when her suspicion is first aroused, she is
unable to decide positively whether she is pregnant. Physicians of
broad experience, possessed of facilities for observation which their
patients cannot employ, may find it necessary to make more than one
examination before they commit themselves to a definite opinion; in
some cases, though very rarely, they must wait for two or three
months to be able to do this.
THE POSITIVE SIGNS.--The earliest absolutely trustworthy
manifestation of pregnancy is the motion of the fetus. The perception
by the mother of these movements, which is spoken of as "quickening,"
generally occurs toward the eighteenth week, if she has been told to
watch for them; otherwise they may pass unnoticed until the twentieth
week or later. At first the motion, felt in the lower part of the
abdomen, is very gentle; it has been variously likened to tapping, or
to quivering, or to the fluttering of a bird's wings. As time goes on
the movements grow stronger and occur more frequently; they are,
however, perceived but rarely throughout the day and seldom interfere
with sleep. Occasionally women are annoyed by the sensation and
complain that the child is hardly ever quiet. Even these troublesome
movements are never a cause for anxiety; but prolonged failure to
feel motion after it is once well established should be reported to
the doctor.
In the first pregnancy the passage of gas through the intestines may
be mistaken for quickening long before the movements of the child are
really perceptible; but those who have once experienced quickening
will not be deceived. Whenever women who have borne children are in
doubt the sensation is almost surely not quickening. Furthermore, in
any doubtful case, the motion should be observed by a physician
before being accounted a positive sign of pregnancy. This precaution
will scarcely delay an absolutely positive diagnosis, since the
proper method of examination reveals these movements to the physician
almost as early as the patient feels them.
About the time these movements become perceptible another positive
sign is available. The physician whose ear has been trained to catch
such sounds when he listens over the lower part of the mother's
abdomen will hear the fetal heart-beat. Other sounds may be audible
there, but the character and the rate of the heart-sounds are
distinctive. Since the child's heart beats almost twice as fast as
the mother's, under ordinary conditions it is impossible to confuse
one with the other. The mother never feels the beating of the child's
heart, but occasionally she will mistake for it the throbbing of her
own blood vessels.
Ability to hear the fetal heart not only provides a means of
confirming the existence of pregnancy in doubtful cases, but also
enables the physician to reassure his patient if she fails
temporarily to feel the child move. Sometimes the presence of twins
is recognized in this way. Toward the end of pregnancy the heart
sounds are also of material assistance in determining what position
the child has permanently assumed.
There is a third positive sign of pregnancy to which the physician
has recourse, but generally it is inapplicable as early as those
already mentioned. In the latter months of pregnancy it is possible
to outline the child through the mother's abdominal wall. Although
this procedure adds little or nothing to our resources for making an
early diagnosis, the information it ultimately affords proves one of
the greatest aids in the practice of obstetrics.
THE PROBABLE SIGNS.--Obviously, phenomena for which the child is
responsible--such as have just been described--supply the most
trustworthy evidence of pregnancy; and these phenomena alone are
accepted as positive signs. But there are earlier manifestations
which intimate very strongly that conception has taken place. Shortly
after pregnancy has become established changes begin in the uterus,
as physicians call the womb, and soon reach the point where they may
be recognized by a simple examination which enables the physician to
express an opinion little less than positive. As one result of
pregnancy, for example, the supply of blood is increased to all the
organs concerned with the reproductive process. Partly on account of
this congestion and partly on account of embryonic development, the
uterus becomes altered in a number of ways. Although these changes
occur regularly in pregnancy, they may also occur when the womb is
enlarged from other causes; therefore, if a physician should make the
diagnosis of pregnancy whenever they were found, he would make it
somewhat too frequently. With a little patience, however, he excludes
the chance of being misled; a second examination, approximately four
weeks after the first, will generally place the existence of
pregnancy beyond question, for under normal conditions the degree of
enlargement which takes place in a pregnant womb during a given
interval is absolutely characteristic.
THE PRESUMPTIVE SIGNS.--Although women are most often led to suspect
that they are pregnant by symptoms which are of such doubtful
significance that they must be regarded as merely presumptive
evidence, the practical value of these symptoms is attested by the
fact that subsequent developments rarely fail to confirm the
suspicion. Perhaps they prove misleading once or twice in a hundred
cases; the number of mistakes is small, because the diagnosis is
commonly made not from only one of these doubtful signs but from a
group of them. In order of importance the doubtful or presumptive
signs of pregnancy are these: (1) cessation of menstruation, (2)
changes in the breasts, (3) morning sickness, (4) disturbances in
urination.
_The Cessation of Menstruation_.--The failure of menstruation to
appear when it is expected is nearly always the first symptom of
pregnancy to attract attention, and, as a rule, when this happens to
healthy women during the child-bearing period--which usually extends
from the fifteenth to the forty-fifth year--it may be taken to
indicate that conception has occurred. But there are exceptions to
this very good rule. Besides pregnancy we are acquainted with several
conditions that cause temporary suppression of menstruation; and to
understand its significance we must learn something of the menstrual
process itself.
Menstruation is a function of the womb and in all probability is
brought about through the influence of the ovaries. The bleeding,
popularly regarded as the entire menstrual process, is, in fact,
indicative of only one of its stages; the others give rise to no
symptoms whatever. What the stages in the menstrual process are, what
relation they bear to each other, and what the significance of the
whole process is, are problems that have been solved with the aid of
the microscope. In this way the mucous membrane lining the womb has
been studied both at the time of the periods and in the interval
between them, and we have learned that it is constantly undergoing
changes intended to facilitate the reception and the maintenance of
an embryo. Anticipating these duties the mucous membrane receives a
more abundant supply of blood; it also increases in thickness and all
the structures which enter into its composition become more active.
Unless conception takes place these preparations, which represent the
most important phase in the menstrual process, are without value; and
therefore failure to conceive means that the mucous membrane will
return to the same condition as existed before the preparations were
begun. The congestion is relieved by rupture of the smallest blood
vessels, and there follow other retrogressive steps which completely
restore the various structures to their former state. Then there is a
pause, though it is not long, until preparatory changes are again
initiated, or, as we say, another Menstrual Cycle is begun. Each
cycle lasts twenty-eight days, and includes four stages, namely, a
stage of preparation, of bleeding, of restoration, and of rest.
Although pregnancy may become established at any time during the
interval between the periods of bleeding, it is more likely to be
established just before a period is expected or shortly after it has
ceased. Furthermore, whenever conception does take place, the
preliminary preparations for the reception of the embryo are followed
by much more elaborate arrangements for its protection and nutrition.
Under these circumstances the hemorrhagic discharge does not appear.
Were there no other condition to bring about the cessation of
menstruation, the diagnosis of pregnancy would be greatly simplified.
But any one can appreciate the fact that diseases of the womb may
interfere with the menstrual process. Menstruation is influenced,
also, by the ovaries. As a result of age, for example, the ovaries
undergo changes which invariably bring about the permanent cessation
of menstruation, called the menopause. This event occurs prematurely
if both the ovaries are removed by operation. In view of these facts
it is not surprising that sometimes ovarian disorders abolish
menstruation. An impoverished state of the blood, or nervous shock
and strain, or constitutional debility may also interrupt the regular
appearance of the menstrual discharge.
The value of menstrual suppression as an evidence of pregnancy is
not, however, to be discounted to the extent that we might expect.
This is true because the ailments which lead to confusion are
relatively infrequent, and also because they exhibit characteristic
symptoms which are foreign to pregnancy. Often these symptoms are
obvious to the patient herself; if not to her, they will be obvious
to her physician. It is about the doubtful cases, naturally, that a
professional opinion is sought, and on that account physicians are
perhaps inclined to overestimate the difficulty women have in
learning for themselves whether or not they are pregnant. As a matter
of fact, it is unusual for a prospective mother to fail to reach a
correct decision--a decision for which she relies chiefly upon the
suppression of her menstrual periods.
It is doubtful whether menstruation ever continues after conception
has taken place. Instances in which the menstrual function is
believed to persist are not uncommon, and yet in all probability the
discharge regarded as menstrual has a different origin. In most cases
it should be interpreted as meaning that there is some danger of
miscarriage. Since miscarriage often occurs about the time a
menstrual period would ordinarily be expected, there is unusual
opportunity for confusing the symptoms. At all events women err much
more frequently in suspecting that they are pregnant than in
overlooking the condition. Indeed, pregnancy is not likely to be
overlooked unless menstruation has been irregular or suppressed for a
month or more previous to conception. Thus, in the case of nursing
mothers in whom menstruation is already suppressed and who are,
moreover, deprived of certain evidence that the breasts give,
pregnancy may sometimes advance several months before it is
recognized.
_The Changes in the Breasts_.--Various sensations in the breasts
are accepted by women as a reliable sign of pregnancy; thus
throbbing, tingling, pricking, or a feeling of fullness will be
mentioned by one mother or another as having given her the first
intimation that she was pregnant. A few women also find their breasts
become tender immediately after they have conceived; this may be so
marked that they cannot bear pressure. But unless such symptoms are
accompanied by definite, visible changes, they have no value as signs
of pregnancy.
About the end of the second month the nipples become larger and more
erectile, and deepen in color. The pigmented, circular area of skin
which surrounds the nipple, called the areola, also darkens. The
shade that the areola assumes will vary according to the complexion
of the individual, growing darker in brunettes than in blondes.
Ultimately, within this pigmented circle a number of elevated spots
appear about the size of a large shot. These spots betray the
presence of tiny glands always located there which, on account of the
better state of nutrition during pregnancy, grow larger, and
generally become visible.
Usually, after two menstrual periods have been missed the breasts
increase in size and firmness, and often the veins which run just
beneath the skin stand out conspicuously. Before very long it is
possible to squeeze from the breasts a fluid which many persons
believe to be milk, though it is really colostrum, a substance that
resembles milk but very slightly. At first colostrum is a clear,
white fluid, but in the later months of pregnancy it becomes yellow
and cloudy.
None of the changes in the breasts are absolutely characteristic of
pregnancy; even the secretion of colostrum has been noted in
association with various other conditions. Furthermore, as a sign of
pregnancy the presence of colostrum is totally deprived of value in
the case of a woman who has recently nursed an infant, for a small
quantity of milk or colostrum often remains in the breasts for months
after the infant is weaned. In general, however, women who have not
been pregnant before should assume that they have conceived if, after
missing a menstrual period, they note the characteristic changes in
the breasts.
_Morning Sickness_.--Soon after conception many women suffer
from nausea and vomiting, especially on rising in the morning.
"Morning sickness" usually passes off in a few hours, although it may
be more persistent. Perhaps this manifestation occurs more frequently
in the first than in subsequent pregnancies, but certainly one-half,
and probably two-thirds, of all prospective mothers suffer from it.
Usually the nausea begins just after a menstrual period has been
missed, and ceases about the third month or a little later.
But morning sickness is never counted an indication of pregnancy
unless taken in conjunction with other symptoms, for individuals who
are not pregnant may also suffer from nausea in the morning. On the
other hand, a number of prospective mothers escape morning sickness
altogether, and a few experience nausea at other times of day.
_Disturbances in Urination_.--It is not an uncommon belief that
some characteristic change occurs in the urine shortly after
conception. But this is not true; at least no change is revealed by
any method of analysis known at present. Yet there are symptoms
associated with the passage of the urine which appear very promptly
and prevail for several weeks. Chief among these is the desire to
empty the bladder frequently; some patients also have difficulty in
urination, and a few experience discomfort with it. All the bladder
symptoms gradually disappear about the fourth month, but become
prominent again toward the end of pregnancy.
Since the inclination to empty the bladder more often than usual may
be due merely to nervousness or to many other conditions, this
symptom taken alone cannot be regarded as a definite sign of
pregnancy. Indeed, it is mentioned, not because of its importance,
but to point out that it is in no way connected with the kidneys, as
patients are sometimes led to believe. It is a direct and natural
result of pregnancy. Since the womb enlarges and tilts forward at a
more acute angle than formerly, it presses against the bladder,
giving the same sensation as when the bladder is distended with
urine.
Although the presumptive signs which we have considered by no means
exhaust the list, all the others are totally untrustworthy. Each of
the more reliable symptoms, as we have seen, must be accepted
cautiously; but taken altogether, except in very unusual cases, they
may be relied upon. _If, for example, menstruation has previously
been regular and then a period is missed, the patient has good reason
to suspect she is pregnant; if the next period is also missed and
meanwhile the breasts have enlarged, the nipples darkened, and the
secretion of colostrum has begun, it is nearly certain that she is
pregnant; whether morning sickness and the desire to pass the urine
frequently are present is of no importance._ But the most
characteristic evidence, we must remember, is not available until the
eighteenth or twentieth week; then the signs of pregnancy are
unmistakable.
THE DURATION OF PREGNANCY.--After the existence of pregnancy has
become assured, perhaps the greatest interest centers about the date
upon which the birth may be expected. Even to approach accuracy in
this prediction the prospective mother must be familiar with certain
facts which she will always observe, but which, unless she
appreciates their importance early in pregnancy, she may fail to
record or to remember. In a few cases, however, such exceptional
information as knowing the date of conception does not lead to an
absolutely accurate prediction. But the deviation from the rule will
be understood only after we understand the rule itself, which is
based upon what we accept as the average duration of human pregnancy,
technically called the period of gestation.
In a broad sense, the period of gestation for each variety of mammal
is determined by the time required for embryonic development to reach
the point where the young may live independently of the mother. This
point is reached more quickly with small animals than with large. The
mouse, for example, generally brings forth its young in three weeks,
whereas the pregnancy of the elephant lasts two years. In human
beings, counting from the time of conception to the time of delivery,
pregnancy continues approximately 273 days. This number is merely an
estimate calculated from hundreds of cases in which there was no
question as to the underlying facts. Individual cases vary notably,
and indicate that two women may become pregnant on the same day and
yet not necessarily be delivered at the same date.
Irregularities in the duration of pregnancy are not limited to man.
Thus, while the mean period of gestation in the rabbit is thirty-one
days, it may be either shorter or longer by as many as eight days.
Similar variations occur in the pregnancies of all animals, and are,
moreover, notably greater among larger animals, since for such
animals the period of gestation is relatively long. For instance, the
accurate observations of veterinarians indicate that the mean period
of pregnancy in the cow is 285 days from the time of conception. This
fact notwithstanding, a competent observer found that, of 160 cows,
67 were delivered before the 280th day; 68 between the 280th and the
290th day; and 25 after the 290th day. Although nothing unnatural was
observed in any instance, the first animal was delivered 67 days
before the last, and in 5 instances gestation continued 308 days.
In ancient times it was believed that the duration of pregnancy was
of even more uncertain length in man than in the lower animals; but
since the eighteenth century thirty-nine weeks have been accepted as
the average duration of the human pregnancy when reckoned from the
day of conception. As this date is seldom known, it is most
convenient to reckon from the first day of the last menstrual period.
Estimated in this way its average duration is 280 days. As this
period corresponds to ten menstrual cycles, physicians prefer to
describe pregnancy as lasting 10 lunar months of four weeks each.
This is equivalent to 9 calendar months, in terms of which its
duration is popularly stated.
THE ESTIMATION OF THE DATE OF CONFINEMENT.--Since pregnancy is not an
absolutely fixed period, we possess no reliable means of predicting
the exact day when it will end. The most satisfactory method of
prediction consists in counting forward 280 days from the beginning
of the last menstruation or, what gives the same result, counting
backward eighty-five days from this date. _To make the calculation
in the simplest way we count back three months and add seven
days_; this addition is made because seven days generally
represents the difference between three months and eighty-five days.
If the last menstruation, for example, began on October 30th, we
count back three months to July 30th and add seven days, which gives
August 6th as the probable date of confinement.
A prospective mother should remember that this prediction is no more
than approximate. The calculation does not give the exact date of
delivery more than four or five times in a hundred cases. It is
accurate within a week in half the cases and within two weeks in
four-fifths. We also know that delivery is somewhat more likely to
occur after the expected date than before it. But perhaps we shall
get the clearest idea of the accuracy of the rule, or better still
of its inaccuracy, if we imagine twenty patients to have the same
predicted date, all of them giving birth to mature infants. The
chances are that only one of these patients will be confined upon the
day predicted; nine will be confined before and ten after it. In all
probability five of those who pass the predicted day will be
delivered within a week and four others within the second week, while
the twentieth patient will not be delivered until three weeks or more
have elapsed.
Such results clearly indicate our inability to make accurate
predictions even though pregnancy is normal in every way. Whenever
patients pass their expected date uneventfully, if they will bear in
mind that the fault lies with the method of prediction and not with
the pregnancy, they will often be saved anxiety. Frequently such
discrepancies are attributable to a false assumption, for our rule
always assumes that the conception took place immediately after a
menstrual period. While this is generally true, the number of cases
in which it occurs just before the period to be missed is by no means
inconsiderable, and in these we should not expect pregnancy to end
until two or three weeks after the day predicted by the rule.
Occasionally patients know the precise day upon which conception took
place, and prefer to estimate the day of confinement from that rather
than from the beginning of the last menstruation. They may do so by
counting back thirteen weeks from the day of conception; but this
method also is subject to error for, as we have noted, the duration
of pregnancy reckoned in this more exact manner is not constant. Such
a calculation rarely offers any advantage over that made from the
menstrual record.
Another method of estimating the date of confinement is based upon
the assumption that fetal movements are first perceived by the mother
toward the eighteenth week of pregnancy; and in consequence twenty-
two weeks generally elapse between quickening and the day of
delivery. Although such a calculation is far from certain in its
prediction, there are instances in which no other calculation can be
made. A nursing mother, for example, may become pregnant before
menstruation has been reestablished. Under these circumstances,
obviously, the date of confinement cannot be estimated in the
ordinary way, and it is then especially important to know the first
day on which the fetal movements were felt. Furthermore, it is
helpful to note this date in every case, since it serves, if for
nothing more, to confirm the prediction made from the menstrual
record. Besides the two methods just described, which are alike in
that they require the patient herself to make the necessary
observations, there is a third method of estimating how far pregnancy
has advanced, by which the physician is enabled to draw his own
conclusions. This method is based upon the fact that the womb
enlarges from month to month during pregnancy at a constant rate. Up
to the end of the third lunar month it cannot be felt through the
abdominal wall; but in the course of the fourth month, on account of
its size, it must rise into the abdominal cavity. At the beginning of
the sixth month the top of the womb is at the level of the navel, and
at the ninth reaches the ribs. The diaphragm then prevents the womb
from going higher; and two or three weeks before the end of pregnancy
it drops several inches, causing a change in the figure which is
noticeable to the patient, since her skirts hang somewhat lower than
before. From this time on she is more comfortable, because the lungs
are not crowded, and there is less interference with breathing.
These alterations in the position of the womb indicate very
satisfactorily the month to which pregnancy has advanced, but not the
week and much less the day. They do not afford a more accurate means
of predicting the date of confinement than does quickening. The
evidence gained from the position of the womb, like that afforded by
the beginning of quickening, generally confirms the prediction made
from the menstrual history; it serves only occasionally to correct
it.
PROLONGED PREGNANCY.--Since birth does not occur in many cases until
the predicted date has been passed, it will be helpful even at the
cost of repetition to sum up what we know in explanation of such
unfulfilled predictions. They are to be explained sometimes by
uncertainty as to the beginning of pregnancy, as for example by the
supposition that conception took place shortly after the last
menstrual period, whereas it actually occurred two or three weeks
later. In a few instances, however, errors of observation or of
calculation will not account for false predictions.
It is generally admitted that second pregnancies average somewhat
longer than first pregnancies; one series of statistics indicates
that the duration increases slightly with each pregnancy up to the
ninth and decreases after that. Pregnancy is protracted more
frequently in healthy women than in those who are not, and again more
frequently in those who are inactive than in those who work. With
twins, contrary to the popular belief, pregnancy is apt to end
before, not after, the expected date. The sex of the child, in all
probability, has no influence upon the duration of pregnancy.
As we might expect, individuality is also a factor in this problem.
Thus, the period of gestation with some women is regularly longer,
with others habitually shorter than the accepted average. Until
experience has demonstrated their existence, generally, such
peculiarities are overlooked. But occasionally they may be detected
from knowledge of the interval between the menstrual periods; an
unusually long interval between them, for example, would lead us to
anticipate a protracted pregnancy.
Any delay after the expected date of birth has arrived taxes the
patience of the prospective mother. The fact, however, that more than
280 days have passed since the last menstruation, does not
necessarily mean that a patient has gone "over time." Such a question
can be decided solely from the weight and length of the child. Judged
in this way, comprehensive statistics indicate that once in several
hundred cases pregnancy may be fairly called prolonged. Even in these
rare instances an examination about the time of the predicted date
makes it clear whether pregnancy should be artificially ended or be
allowed to proceed to its natural conclusion.