Amniotic Fluid (The amniotic fluid contains 240 currents of)

AMNIOTIC FLUID - The amniotic fluid contains 240 currents of amniotic epithelium and sometimes leukocytes (Daniel, Vinogradova). In healthy pregnant women and parturients, the amniotic fluid is sterile in the vast majority of cases (Aleksapolsky). In pathological cases (leukorrhea, febrile condition, albuminuria, syphilis, etc.), a significant number of leukocytes, lymphocytes, often deformed erythrocytes, and microorganisms (streptococci, staphylococci, and rod-shaped forms) appear in them (Vinogradova).-The amount of amniotic fluid can vary greatly even within physiological limits. Generally, it is accepted that during the first 5 months, as pregnancy progresses, there is a gradual increase in the amount of fluid compared to the size of the embryo, and then the weight of the fetus increases more rapidly, and there is relatively less fluid (Spiegelberg, Runge, Lepage). According to precise measurements by Charlotte Lehn, the amount of amniotic fluid at the end of a normal pregnancy averages 1,070 g (in primiparas - 1,000 g, in subsequent pregnancies - 1,200 g). The relationship between the amount of amniotic fluid and various factors - the length and weight of the fetus, sex, size of the placenta, length of the umbilical cord, chemical composition of the fluid, etc. - has not been established. Cryoscopic research has shown that the freezing point of amniotic fluid ranges from -0.475° to -0.495°. The specific electrical conductivity on average (from 4 cases) is 0.0107 (in cm^-1 ohm^-1). The electromotive force in volts on average is 0.296. The study of the chemical composition of amniotic fluid in women was carried out by a number of authors, and initially the results were extremely contradictory. In 1877, the fundamental work of Prochownik was published, whose data were accepted by all. Prochownik showed that the composition of amniotic fluid is characterized by a certain constancy with minor quantitative fluctuations (however, Prochownik's research does not provide a complete determination of the chemical composition of amniotic fluid). Later, some other components of amniotic fluid were identified: P₂O₇, sulfates, phosphorus, traces of magnesium, creatine, mucin, cholesterol, soaps, allantoin, protein (albumin, globulin), and many enzymes (pepsin, diastase, lipase, fibrin ferment) (Bruno Wolff). Vinogradova (1928) studied the inorganic residue of amniotic fluid in women. Based on chemical and spectral analysis of 22 samples, the complete qualitative and quantitative composition of the fluid was obtained, the "probable" chemical composition was calculated, and the average content of amniotic fluid was determined.-The inorganic composition of amniotic fluid: table salt 0.050-0.126%, potassium chloride 0.010-0.07%, magnesium sulfate 0.01895-0.03306%, calcium bicarbonate 0.49-1.56%, iron oxide 0.001-0.29%, phosphorus anhydride 0.00003-0.02198%, water 94.33-98.86%, organic substances in amniotic fluid range from 0.5% to 4.0%. These studies showed that the composition of amniotic fluid is characterized by great constancy with respect to inorganic substances with minor quantitative fluctuations.-In spectroscopic analysis (Goralevich and Vinogradova), in addition to the usual elements, the appearance of a series of unmeasurable lines in the center of the violet part of the spectrum was noted (constant flickering). Electrometric measurement of the calcined residue of the fluid confirmed ionization of the air in the chamber of the instrument, giving from 0.013 to 0.150 units, Mach, per 1 cm² of radiating surface. The minimum amount of ionizing substance found was attributed to the presence of radioactive substances - thorium or actinium salts. - Amniotic fluid also contains relatively large amounts of hormones from some endocrine glands (Aranovich, Frank). Thus, per 1 liter of amniotic fluid there are about 300 M.E. (mouse units) of the female sex hormone, and approximately the same amounts should be considered for the presence of prolane hormone from the anterior pituitary gland in them. Origin of amniotic fluid. In ancient times, it was believed that amniotic fluid originated from fetal secretions, urine, sweat (Empedocles, Galen, Hippocrates), due to delayed menstruation (Vesalius), from the ovary or from the follicle. Experimental works of the second half of the 19th century were extremely contradictory. Scanzoni, Matveev considered the maternal organism as the source of amniotic fluid and as proof cited the transition of aromatic substances into the fluid. K. Braun, Preyer, and especially Jungbluth attributed the production of amniotic fluid to the embryonic part of the placenta, from where the fluid passes into the amniotic cavity through the finest capillaries (vasa propria Jungbluthi). Other authors, based on experimental work on the exchange of substances between mother and fetus, do not allow for intrauterine urination by the fetus and attribute the formation of fluid mainly to transudation from maternal blood and partly only from the vessels of the placenta. In recent decades, thanks to new anatomical-physico-biochemical research and the data obtained, the long-prevailing but poorly substantiated viewpoint that amniotic fluid forms as a result of mechanical suction of serum from maternal blood has been abandoned. Research by a number of authors has established that amniotic fluid is a product of the secretory activity of the embryonic amniotic epithelium located at the site of the placenta, where special formations - vacuoles - were found, in which fluid accumulates, which empties into the amniotic cavity. These cylindrical cells with vacuolar inclusions, in the opinion of some authors, should be considered as secretory cells. The regulation of accumulation and outflow of amniotic fluid is still poorly understood. The physiological role of amniotic fluid is not fully revealed. The mechanical significance of amniotic fluid is indisputable, as they contribute to uniform stretching of the uterine walls, prevent adhesion of the fetus to the walls of the fetal egg and curvature of the infant's limbs, facilitating its movements and making them less sensitive for the mother. Amniotic fluid also balance the pressure of the uterus on the placenta and on the umbilical vessels. Amniotic fluid play no less a role during childbirth: they contribute to uniform dilation of the uterine cervix, moisten the birth canal, and as the so-called hind waters prevent the uterus from complete contraction and premature disruption of placental circulation. The question of whether amniotic fluid serve as nutrients for the fetus has not yet been finally resolved. Experimental work and observations on the nutrition of embryos of lower animals may confirm these assumptions; the chicken embryo from the 17th day by pecking absorbs its own waters. Mammals (cow, pig, sheep, etc.) also as a rule from the second half of intrauterine life absorb amniotic fluid (Kistyakovsky, Dederlein). Kistyakovsky, Marschand, and Zaretsky proved the presence on the amnion of a number of animals (cow, pig, mouse, guinea pig) of epithelial plaques with a high glycogen content, which then enter the fetal stomach. Zaretsky also studied the question of the delivery of carbohydrates to the developing animal organism and investigated the uterine mucosa in animals and in women. In pregnant women, he always found grains and lumps of glycogen in decidual cells and outside them, mainly in decidua serotina (basalis); in non-pregnant women, he could not detect glycogen. In the human placenta, according to Brindeau and Langhans, glycogen is present throughout pregnancy; in the placental part of the amnion, Polano discovered a saccharifying enzyme, and thus it was possible to trace the path of glycogen from the maternal organism to the amnion and its breakdown under the influence of the saccharifying enzyme. In recent years, Bondy, Polano, and his students have proven the physiological significance of the amnion as an organ serving for the delivery of nutrition to the fetus. Precise chemical research found in the parietal free amnion a number of lipoids and their breakdown products (fats, fat-like substances, fatty acids, soaps, glycerol, cholesterol) and a lipolytic enzyme. In the subamniotic tissues toward the decidua, a progressive increase in small fat droplets was discovered. It follows that fat and glycogen are delivered to the fetus from the uterine mucosa. Approaching the amnion, these smallest fat droplets under the influence of lipolytic enzymes break down into their components and enter the amniotic fluid. In the latter, a lipolytic enzyme has not been found (Herman). In histological research, it was also found that up to the 5th month of pregnancy, fat droplets impregnate the upper layers of the fetal skin, and then fat accumulation occurs in the upper parts of the small intestine (Polano).-Regarding the transfer of protein substances to the fetus, exact data are not yet available, but nevertheless enzymes that break down proteins (chymosin) and fibrin ferment were found in the amnion. The presence of many components of the protein molecule in amniotic fluid (by analogy with the transfer of fat and carbohydrates to the fetus) allows one to assume that protein particles can also be absorbed by the fetus through amniotic fluid.

The physiological role of amniotic fluid is not fully revealed. The mechanical significance of amniotic fluid is indisputable, as they contribute to uniform stretching of the uterine walls, prevent adhesion of the fetus to the walls of the fetal egg and curvature of the infant's limbs, facilitating its movements and making them less sensitive for the mother. Amniotic fluid also balance the pressure of the uterus on the placenta and on the umbilical vessels. Amniotic fluid play no less a role during childbirth: they contribute to uniform dilation of the uterine cervix, moisten the birth canal, and as the so-called hind waters prevent the uterus from complete contraction and premature disruption of placental circulation. The question of whether amniotic fluid serve as nutrients for the fetus has not yet been finally resolved. Experimental work and observations on the nutrition of embryos of lower animals may confirm these assumptions; the chicken embryo from the 17th day by pecking absorbs its own waters. Mammals (cow, pig, sheep, etc.) also as a rule from the second half of intrauterine life absorb amniotic fluid (Kistyakovsky, Dederlein). Kistyakovsky, Marschand, and Zaretsky proved the presence on the amnion of a number of animals (cow, pig, mouse, guinea pig) of epithelial plaques with a high glycogen content, which then enter the fetal stomach. Zaretsky also studied the question of the delivery of carbohydrates to the developing animal organism and investigated the uterine mucosa in animals and in women. In pregnant women, he always found grains and lumps of glycogen in decidual cells and outside them, mainly in decidua serotina (basalis); in non-pregnant women, he could not detect glycogen. In the human placenta, according to Brindeau and Langhans, glycogen is present throughout pregnancy; in the placental part of the amnion, Polano discovered a saccharifying enzyme, and thus it was possible to trace the path of glycogen from the maternal organism to the amnion and its breakdown under the influence of the saccharifying enzyme. In recent years, Bondy, Polano, and his students have proven the physiological significance of the amnion as an organ serving for the delivery of nutrition to the fetus. Precise chemical research found in the parietal free amnion a number of lipoids and their breakdown products (fats, fat-like substances, fatty acids, soaps, glycerol, cholesterol) and a lipolytic enzyme. In the subamniotic tissues toward the decidua, a progressive increase in small fat droplets was discovered. It follows that fat and glycogen are delivered to the fetus from the uterine mucosa. Approaching the amnion, these smallest fat droplets under the influence of lipolytic enzymes break down into their components and enter the amniotic fluid. In the latter, a lipolytic enzyme has not been found (Herman). In histological research, it was also found that up to the 5th month of pregnancy, fat droplets impregnate the upper layers of the fetal skin, and then fat accumulation occurs in the upper parts of the small intestine (Polano).-Regarding the transfer of protein substances to the fetus, exact data are not yet available, but nevertheless enzymes that break down proteins (chymosin) and fibrin ferment were found in the amnion. The presence of many components of the protein molecule in amniotic fluid (by analogy with the transfer of fat and carbohydrates to the fetus) allows one to assume that protein particles can also be absorbed by the fetus through amniotic fluid.

The presence of a specific, constant inorganic composition of the waters at all stages of pregnancy indicates the fine specificity of this fluid as a medium for the growing organism. It is known that the function of salts is no less important and varied than the function of the organic components of food (Abderhalden), and therefore one cannot but recognize that the amniotic fluid provides the fetus not only with sugar and fat, but (with great probability) also with salts, proteins, and water. The presence of hormones and minimal doses of radioactive elements in the amniotic fluid allows for the possibility of recognizing their activating property. Thus, one can come to the conclusion that the amniotic fluid has significance in the development and birth of the fetus not only as a mechanical factor, but that they play a certain role in the nutrition of the fetus and in providing energy for its rapid growth and development.