Obviously we lack subjective observations of intrauterine life, but many objective data have been obtained. I have already mentioned the fact that the fetal kidneys function in utero and thevoids into the amniotic fluid. The intestines are also active, and a thick, viscid, tarlike excrement (meconium) is found in the lower bowel. Under normal conditions meconium is not excreted until after delivery. The fetal heart and some phases of fetal movements have already been discussed; there are several additional facts about intrauterine activity which merit discussion.
The fetal movements felt by patient and doctor are usually the thrusting and bending of arms and legs. The motion of the legs is more extensive than that of the arms, and therefore if movements appear most active in the upper abdomen it is likely that the fetus presents by the head. If in breech presentations a foot protrudes from the vagina during labor, its movements can be seen hours before birth. If the foot is pinched the child attempts to withdraw it, and if the sole is scratched the toes bend wildly. Occasionally a hand may present along with the head (compound presentation) during labor, and if on vaginal examination the obstetrician should shake hands with his unborn patient, the baby’s fingers squirm in a most unpleasant fashion. In face presentations sucking movements are produced if the examiner inserts a finger into the child’s mouth. Ahlfeld, a very competent German scientist, states that the fetus even sucks its fingers in utero. He reports the case of a child born with a swollen thumb; immediately after birth it put the swollen member into its mouth and sucked. Fetal hiccups have been repeatedly observed by both physician and patient. The movements are short, quick regular jerks of the child’s shoulders and trunk, fifteen to twenty a minute. They can be seen and felt, and they resemble ordinary hiccups except for the absence of the stridor, the harsh noise. An attack of intrauterine hiccups usually lasts about fifteen minutes and may recur several times before delivery.
As stated earlier in this article, the fetus does not breathe in utero; the work of the lungs is carried on by the placenta and the mother’s blood. However, there is much evidence that the chest of the fetus moves rhythmically in a typical respiratory pattern during the last part of pregnancy. The observation of prenatal respiratory movements was first made in 1888 and has been corroborated several times since. These observers noted a slight rising and falling of the abdominal wall of the mother near the navel; it occurred sixty to eighty times a minute and was most marked in the region which overlay the child’s chest. The series of movements were intermittent, ceasing after several minutes and recurring later.
In more recent investigations the abdomen of a rabbit at term or past term was immersed in a largeof special fluid (Ringer’s Solution) kept constantly at body temperature. The abdominal cavity of the living animal was opened under spinal anesthesia, and the intact uterus eviscerated. Several minutes later, when the fetuses had become acclimated to the change in environment, their respiratory movements commenced. These were distinctly seen through the semitransparent, thin-walled uterus and could be clearly differentiated from other fetal movements.
It is hard to believe, but nevertheless true, that occasion- ally the human fetuswhile still in utero. Many cases have been reported by reliable observers, so that even the most skeptical must accept this bizarre occurrence. In every such instance some operative procedure had allowed air to enter the cavity of the uterus before birth, usually either a version (turning of the child) or a operation. The cry is clearly audible and sounds as though it came from an infant hidden under the covers. This phenomenon is termed vagitus (Latin: ‘the of an infant’) uterinus.
Another precocious trick has been discovered in the repertoire of the fetus. The reaction of the fetus to vibratory stimuli applied to the mother’s abdomen has been tested. The stimulus used was an ordinary tuning-fork with a frequency of 120 oscillations per second. No response was noted until the twenty-ninth week, but from this time on all the fetuses responded by an acceleration in the rate of heartbeat, and some by an increase in fetal movements. The speeding of the fetal heart became progressively greater as term was approached; in the seventh month there was an average increase of eight beats, in the eighth month thirteen, and during the last month fourteen. The explanation for this interesting response is uncertain. It probably represents relayed tactile stimulation rather than true hearing. Other observers have reported isolated instances of fetal reaction to vibratory sounds. A patient noted that her fetus stirred vigorously whenever the audience applauded at a concert.
Almost every woman near term attests to the fact that the fetus alternately sleeps and wakes. An hour or several hours of quiet will be replaced by a period of obvious fetal activity. Some believe that there is correlation between the extent and degree of prenatal activity and the later makeup of the individual. The tense, hyperkinetic child leads a restless life even in utero, while the placid, even-dispositioned youngster is quiet in the womb.
There is no evidence, of course, that any of this fetal activity is accompanied by consciousness. Every instance cited seems to be a matter of involuntary response to various stimuli. Even the newborn baby seems to have very little, if any, use for the upper brain, the cerebral hemispheres.