Maturity

Maturity, the term conventionally used to denote the degree of fetal development. A fetus is considered mature or full-term if born at the end of the 10th lunar month of intrauterine life and in any case not earlier than 38 weeks. Its growth at this time averages 50 cm, weight 3,000–3,300 g. The circumference of the head, according to Fehling, is calculated at 34–35 cm. According to numerous measurements by Kasper-Liman, the average head dimensions in boys are: longitudinal 10.8 cm, transverse (interparietal) 8.5 cm, large oblique (diagonal) 12.6 cm; in girls: longitudinal 10 cm, transverse 8.3 cm, large oblique 12 cm. According to Pobedinsky: the longitudinal diameter, from the glabella to the most projecting point of the occiput, is 12 cm; the large transverse diameter (interparietal) is 9¹/₄ cm, the large oblique, from the chin to the most distant point of the occiput, is 13¹/₂ cm. According to Gruzdiev: longitudinal 11³/₄ cm, large transverse 9¹/₄ cm, large oblique 13¹/₂ cm. In addition, the greatest width of the shoulders and the distance between the femoral trochanters are measured, which are approximately equal to the large oblique and transverse diameters, respectively. In a fully healthy, mature fetus, the skin is not wrinkled, of a pale-pink color, the subcutaneous fat layer is well developed, so the trunk and limbs appear rounded. Lanugo is abundant on the shoulders and barely noticeable elsewhere. The hair on the head is quite dense, 1.5–3 cm long. The cartilages of the nose and ears are dense and elastic. The nails have the property of horny tissue and on the hands usually overhang, while on the feet reach the ends of the fingers. The testicles are in the scrotum. In girls, with a normally developed subcutaneous fat layer, the large labia come together and cover the small ones. At the lower cartilaginous ends of the femoral bones, an ossification center (Becklar center, see) is contained. On putrefied corpses, it is less distinguished by its red color due to bloody impregnation of the cartilage. Often the ossification center appears at the upper end of the tibia, in the cuboid bone, and exceptionally in the epiphysis of the humerus. The average length of the umbilical cord is 50 cm, the average weight of the afterbirth is 500 g. Then a number of anatomical signs are usually cited, which hardly have any significant importance, as they are very variable and in general not very characteristic of a mature fetus. In particular, the width of the anterior fontanelle (2 cm), the position of the umbilicus slightly below the middle of the abdomen, i.e., closer to the pubic symphysis than to the xiphoid process of the sternum, as well as the average weight of internal organs, the length of the small and large intestines are noted. To the most constant and reliable signs of maturity should be attributed the growth of the fetus and the presence of an ossification center in the lower epiphysis of the femoral bones, although even here fluctuations are possible. Thus, the magnitude of growth in mature fetuses can most often vary within 46–56 cm. Kasper-Liman determines the minimum body length of a mature fetus at 41.8 cm. The ossification center in the lower epiphysis of the femoral bones appears in exceptional cases at the end of the 8th month, is more often encountered in the 9th and most often in the 10th lunar month. In general, its presence gives grounds to assert that the fetus is mature or close to it. However, even in the absence of an ossification center, one cannot dispute the maturity of the fetus, since in all other respects it may be absent despite certain maturity. Sometimes the ossification center is observed only on one side. The presence of an ossification center, according to Hartmann, occurs in 88.24%, and according to Liman in 96.62% of mature fetuses. Other signs of maturity are more variable and less reliable. The weight of a mature fetus may not reach 3,000 g, and on the other hand may exceed 4,000 g. According to Kasper-Liman, the minimum weight of a mature fetus is 1,750 g. A case is described (Martin) where the weight of a fetus extracted after perforation of the head was calculated at 7,470 g. It must be borne in mind that the fetus may lose weight already after birth, both prenatally and postnatally. In the first 4–5 days after birth, the weight decreases by 130–200 g due to cutaneous perspiration and disappearance of fat. The processes of putrefaction, maceration, and mummification occurring after death also lead to a drop in the initial weight. In view of the dependence of maturity signs on individual fluctuations in fetal development, practically one has to take into account all moments influencing the formation of the fetus as much as possible, such as racial peculiarities, heredity, the constitution of the parents, the state of nutrition and the age of the mother, the number of births, pregnancies and their course; some researchers (Jung) indicate that an increase in fetal weight in successive pregnancies is observed up to the age of 30 for women; in multiparous women, children are larger than in primiparas. In addition, in pathological pregnancy (twins, syphilis, etc.), significant deviations from the norm also occur in the development of the fetal egg. The sex of the child also has significance: the weight and length of girls are on average slightly less than those of boys. Thus, to determine the maturity of the fetus, it is necessary to take into account the entire set of signs characterizing this condition, and first of all the body length, although in a specific case it is still far from always possible to express a completely definite opinion. This should be especially remembered when resolving questions arising in forensic medical practice.