Fetal development

“ We have seen that after the first month of pregnancy the placenta serves the fetus as a combined respiratory and digestive apparatus, not alone in supplying the oxygen and nourishment requisite for life and growth, but also in excreting the broken-down products of fetal life. ”

“ 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. ”

“ There may be an abortion, when the fetus and membranes are partly or completely extruded from the fimbriated end of the tube into the peritoneal cavity; or a rupture of the tube, when the fetus, with or without the membranes, may be expelled into the peritoneal cavity, or between the folds of the broad ligament. If the greater part of the placenta remains attached to the site of its development, in the case of a ruptured tube, it is possible for the fetus to live and grow and even go to term. ”

“ Nutriment is no longer merely absorbed by the succulent embryonic cells of the ovum from the tissue in which they are in contact, but the embryo is forced to seek sustenance through those now fully-developed tufts of the chorion—from the proper site, the decidua serotina and the surrounding vessels—directly from the uterine structures. If hemorrhage interferes or disease prevails, the healthy growth of the ovum is checked, and a morbid development ensues, to result sooner or later in death of the embryo and expulsion. ”

“ As a variety of the third kind of sterility, sterility due to incapacity for implantation or further development of the ovum, must be classed the cases in which, though conception and implantation of the ovum are known to occur, and the first stages of development of the embryo certainly take place, the woman proves incapable of giving birth to a viable infant. ”

“ Compare Brief for Scholars of Jurisprudence as Amici Curiae 12–14, and n. 32 (emphasis deleted) (“ ‘a quick child’ ” meant simply a “live” child, and under the era’s outdated knowledge of embryology, a fetus was thought to become “quick” at around the sixth week of pregnancy) , with Brief for American Historical Association et al. as Amici Curiae 6, n. 2 (“quick” and “quickening” consistently meant “the woman’s perception of fetal movement”) . We need not wade into this debate. ”

“ At the same time, the viability standard takes account of the undeniable fact that, as the fetus evolves into its postnatal form, and as it loses its dependence on the uterine environment, the State's interest in the fetus' potential human life, and in fostering a regard for human life in general, becomes compelling. ”

“ The life of the fetus, therefore, is absolutely contingent upon an uninterrupted, two-way flow of blood through the cord.
The Fetus. In tracing the development of the ovum after its implantation in the uterine lining, we begin, as previously stated, with a shaggy-looking vesicle, containing fluid, with a clump of cells hanging toward the centre from their point of attachment on the inner surface of the sac. This clump develops into the embryo. ”

“ GROWTH AND PHYSIOLOGY OF THE FETUS Although the fetus at term is in many respects simply a diminutive, immature man, or woman, its anatomy and physiology present certain characteristics which have adapted it to a protected existence in a sac of fluid. Some of the fetal structures and functions become increasingly active after birth, while others subside and disappear. ”

“ The uterus also becomes softer in tubal pregnancy, and the cervix softens somewhat, though not so much as in a uterine pregnancy.
If the woman and the fetus survive the many dangers that accompany the progress of tubal gestation, the development of the fetus will go on to full term, and then the phenomenon of spurious labor will come on. ”

“ But what determines the end of the pregnancy? Is it merely the increasing distension of the uterus by the developing foetus? This could scarcely be the case in the Marsupials in which the foetus when born is quite minute. Nor can we attribute parturition to renewed ovulation, for this occurs in Dasyurus only once a year. All we can suggest at present is that a certain periodic development takes place by heredity in presence of the hormones exuded by the fertilised ovum and the embryo developed from it. ”

“ None the less, bleeding, however moderate, should always excite suspicion, as we know it usually denotes the breaking to some degree of the connection between mother and child. The extent of the separation usually determines the degree of the hemorrhage, which in turn indicates the seriousness of the accident. The fate of the fetus will depend upon the area of placenta, which has been incapacitated. Flooding, however, always imperils the fetus, and generally warrants the inference that so much of the placenta has been separated as to render further development impossible. ”

“ There is no doubt, however, that the mother's environment during pregnancy is in general very important for the perfect development of the intrauterine child. Many more deformed births are reported after times of stress and trial, as, for example, after the sieges of great cities, notably the siege of Paris in 1871, and such scenes of desolation as occurred during the thirty years' war in Germany. ”

“ If the disturbance causing the abortion has been of rapid progress, the cavity is large, the embryo approximating in development the period of expulsion; whilst if the changes have taken place slowly, the walls are thick, the cavity small, and the embryo may appear merely as a small mass pendent from the navel-string, or may have entirely disappeared, and can be traced only by the fine detritus in the amniotic fluid, the cord itself perhaps only in part remaining, and even this may have disappeared. ”

“ That developmental defects of the uterus, even when they are not such as render conception impossible, may yet often give rise to sterility, has been already explained in writing of the conditions of the uterus which prevent the contact of ovum and spermatozoon; for defects of development which are not sufficiently severe to prevent this contact, may yet suffice to render the uterus unfit for the implantation and incubation of the fertilized ovum. ”

“ In our every-day way of speaking, fertilization means conception; it is the instant in which a living being begins its existence. There is no longer the slightest excuse for confusion regarding the period at which the life of the unborn child begins. Before the significance of fertilization was understood, it was perhaps not unreasonable to believe that life began with quickening or about the time the fetal heart-sounds could be heard. ”

“ After one has traced the development of the human body in the uterus, and even faintly understood its growth and method of nourishment, it is impossible to believe that the mother’s thoughts or experiences could in any way deform or mark her child, or alter its sex. That the mother’s “reaching up,” for example, could slip the cord around the unborn baby’s neck is manifestly absurd, as well as the previously mentioned superstitions about the eight-month baby’s slender chances for survival. ”

“ Mere arrest of development of a part may arise from accidental disease of the embryo; hence vital organs are left out, or portions of organs, like the dividing walls of the heart, are omitted. Sometimes an older fetus is inclosed in the body of another, each having started independently from a separate ovum, but the one having become embedded in the semifluid mass of the other and having developed there simultaneously with it, but not so largely nor perfectly. ”

“ A new human being is the ultimate result of conception, but the chorion, amnion, placenta and umbilical cord must also be created to serve as aids in building and protecting the developing child during its uterine life. The part played by these accessory structures is so vital, in spite of being temporary, that it will be well for us to look into their origin and functions before considering the fetus itself which they serve. ”

“ Since the embryo is constantly moving during this time, it quite evidently has no attachment to the mother and cannot, therefore, derive any great amount 65of nourishment directly from her. The growth and development to this point, then, must be due chiefly to inherent powers within the mass of cells itself. ”

“ In every pregnancy the placenta serves in this way as an organ of nutrition, arranging for the passage of food from the mother's blood to the fetal circulation. Occasionally, it is interesting to observe, the placenta performs a very different function, namely, the protection of the unborn child from diseases that may attack the mother. It is able to afford such protection, because the coating of the villi is not permeable to all sorts of substances. In order to pass through their walls, material must be in solution ”

“ For this reason, meconium stained fluid escaping during labor in a head presentation may be taken as an evidence of imminent asphyxiation, due to an interruption of the umbilical circulation.
The head is the most important part of the fetus, from an 89obstetrical standpoint, since the process of labor is virtually a series of adaptations of the size, shape and position of the fetal skull to the size and shape of the maternal pelvis. And since the pelvis is rigid and inflexible the adjustment must all be made by the fetal head, which is mouldable because of being incompletely ossified at birth. ”

“ Once started on the road to development, the embryo is so thoroughly subject to inner laws that nothing from without can modify or change the direction of its growth except some physical cause which interferes with the blood supply. An adequate supply of pure blood is the principal requirement of the growing organism. Whatever interferes with the blood supply or in any way affects its purity, has an injurious affect upon the embryo. There is not the least doubt that lack of nutrition and serious ill-health on the part of the mother have an extremely bad effect upon the unborn offspring. ”

“ The comparative growth of the fœtus infinitely surpasses that of its whole future existence. But the exact age of uterine embryos, and of abortives, is, in some degree, conjectural. Before the seventeenth day after conception, its rudiments are not even visible to the naked eye: the glary ovum has then slidden down from the ovarium, through one of the lateral tubes into the womb. The size of an abortion, comprehending the fœtus, its membranes, waters, and placenta, at the end of six weeks, does not exceed in size that of a pigeon’s or hen’s, and in three months, a goose’s egg. ”

“ The obstetrical forceps have been of such great service in diminishing the number of still-born infants that they were once called the child's instrument. The need of its employment in behalf of the child may be determined by careful observation of the fetal heart-sounds, which are heard over the mother's abdomen, and by means of which one may learn the condition of the child. Signs of danger are extremely uncommon so long as dilatation of the womb is not complete, for any strain which labor may impose upon the child will usually occur during its passage through the pelvis. ”

“ The experience of ages has firmly established the fact that the fetus is expelled when ready to enter the world, or as we say, when it has become mature. But how does the fetus assert its maturity? There is the kernel of the matter; that is the real problem, a problem for the solution of which, happily, we possess better facilities than have heretofore existed. One solution that has been suggested assumes that the fetus loses ultimately its power to assimilate the nourishment provided through the mother's blood. ”

“ That the embryo probably lives in utero in virtue of its own life-principle, even through the entire period of gestation, (51, 56, and 58,) is rendered probable by many facts related by unimpeached authorities, which go to prove that when the whole intact Ovum has been expelled at an advanced period of gestation, or at the natural termination of that period, the fœtus has continued to live, and the circulation of the blood has not ceased for an instant during a space of time of from nine minutes to a quarter of an hour. ”

“ In Ovum 19 there was nothing in the least analogous. Though the placenta is imperfectly formed; even in its filiform or mossy or primitive texture, it might serve and has served the purpose, of forwarding the nutrition and growth of the fœtus. The disease which destroyed the latter, being of an inflammatory nature, must have been more rapid in its effect. It put an end to life before there could have been time for growth to be much affected. ”

“ By mandating tests to determine fetal weight and lung maturity for every fetus thought to be more than 20 weeks gestational age, the statute requires physicians to undertake procedures, such as amniocentesis, that, in the situation presented, have no medical justification, impose significant additional health risks on both the pregnant woman and the fetus, and bear no rational relation to the State's interest in protecting fetal life. ”

“ In case pregnancy has occurred before the deformity is discovered, and it is then found that a full grown child cannot be born, premature delivery must be brought on; or, in other words, the Uterus must be made to expel the child before the full term, while it is yet small enough to pass through the Pelvis. This operation is of course only allowable when needed to preserve life, or to escape great suffering and danger. ”