Multiple Pregnancy

Multiple pregnancy, the development of two or more fetuses during a single pregnancy; occurs relatively frequently. Twins are observed on average in 1:80 pregnancies, while pregnancies with a larger number of fetuses occur significantly less frequently and follows the generally accepted Hellin's formula (n): twins-1:80, triplets-1:80²=1:6,400, quadruplets-1:80³=1:512,000, quintuplets-1:80⁴=1:40,960,000, etc. According to Guzzoni, in 50 million births: twin was observed in 1:87 births, 1 triplet in 1:7,108, 1 quadruplet in 1:757,000, and 1 quintuplet in 1:41,600,000 births. The literature contains descriptions of three cases of pregnancy with six fetuses and one with seven (Engelhorn). Collective statistics from Russian authors show that in the USSR, in 2,056,244 births: 34,100 twins (1:60.3 births), 556 triplets (1:3,678.6), 4 quadruplets, and 1 quintuplet. Considering that in the USSR approximately 6 million births occur annually, the number of multiple births will be about 100,000. Obviously, this phenomenon has great clinical and practical significance. Regarding the development of fetuses from one and two eggs, as well as the structure of the placenta and membranes-see Twins and Pregnancy, rare forms of ectopic pregnancy. Here it should only be noted that the possibility of superfetation is recently supported by the observation of Belyaeva, who described a well-preserved fetus of 5-weeks age and another of 12-weeks. Furthermore, while the role of heredity on the mother's side is not questioned by most authors, the matter is by no means as definite regarding the father. Shaternik cites in this regard a very demonstrative case. A woman, having a husband who was a twin, gave birth to twins 9 times. After marrying another man, she gave birth to a single child three times. There were no multiple births in her family. Strassmann (without indicating the source) speaks of a Russian peasant, Vasiliev, who with his first wife had 4 sets of quadruplets, 7 sets of triplets, and 16 sets of twins, and with his second wife-2 sets of triplets and 6 sets of twins, a total of 87 children, of whom 84 were alive. Unfortunately, there is no information about the heredity of his wives. Multiple pregnancy is observed more frequently in mature age and predominantly in multiparous women. Thus, according to Strassmann, out of 824 multiple pregnancies, it was observed up to 19 years (inclusive) only 12 times, from 20 to 28 years-209 times, from 29 to 37 years-345 times, and later-98 times. According to Mikhailov, in 851 multiple pregnancies: up to 19 years-45 times, from 20 to 29 years-454 times, and older-352 times. Multiple pregnancy occurs more frequently the more pregnancies there have been and the older the women are (Viridarsky and Chapin). Only after 40 years does the percentage of multiple pregnancy decrease. Triplets, according to Mirabeau and Mikhailov, are most frequently observed in the fourth decade of a woman's life. Regarding the sex of the fetus, the predominance of boys is also noted here. According to Meckel-Veit, in 299,928 twins there were 105 boys per 100 girls. It should be noted that among conjoined twins there were no opposite-sex pairs. This indicates that what occurred was not fusion, but insufficient division of the original primordia. In 2,950 cases of triplets (Guzzoni), 906 times 2 boys and 1 girl were born, 705 times-3 boys, 695 times-3 girls, and 644 times-1 boy and 2 girls.--The weight of the fetus is usually less than in singleton pregnancies, approximately by 500-600 g, however in 10% fetuses of 3,000-4,000 g and even more are observed. Only about 5% of twins have the same weight, the others differ by tens and hundreds of grams, and some by 1,000-2,000 g or even more. The length changes accordingly. For example, a child weighing 3,650 g was 50 cm in length, while the other twin weighing 1,600 g was only 39 cm. That such a difference in weight does not depend on fertilization at different times is shown by the presence of similar deviations in monozygotic twins. The heavier fetus is usually born first, especially in monozygotic twins.--Longitudinal positions and head presentations are also the most frequent here. However, the percentage of transverse positions and unfavorable presentations-breech, brow, and face-is significantly higher than in singleton pregnancies (this will be discussed in more detail in multiple births). As for the course of pregnancy, the general processes and changes in the organs proceed in it just as in singleton pregnancy. There are, however, significant differences. The uterus enlarges significantly more, and if at the end of a singleton pregnancy it contains about 5,000 g, in multiple pregnancy it contains 8,000-10,000 g, and sometimes even more than 12,000 g. In the above case of triplets, the fetuses with the placenta and amniotic fluid weighed about 12,000 g. The placenta in twins often weighs 1,000 g or more; there is also a tendency to polyhydramnios. The huge area of the placenta in contact with the uterus can lead to a more significant entry of chorionic elements into the mother's circulatory system, which together with the abundant influx of metabolic products of two or more fetuses increases the work of protective and excretory organs. To this is added the hormonal activity of the placenta and fetuses, causing a corresponding reaction in the mother's endocrine glands. Purely mechanical and nervous influences associated with increased compression and stretching of individual parts should also be noted. As a result, various phenomena of malaise characteristic of pregnancy occur here more frequently and in a more severe form, often crossing physiological boundaries and leading to general exhaustion and disease of individual organs. Thus, nausea and vomiting appear earlier, more frequently and severely, sometimes progressing into the so-called intractable vomiting. Nervousness and the burden of pregnancy progress, especially in the last months, when due to the sharp increase in the size of the uterus, the diaphragm is elevated, the lungs are constricted, and even the heart is compressed, resulting in shortness of breath, palpitations, and disturbances in cardiac function. The intestines work insufficiently due to compression of its lower parts by the uterus, and partly due to the low mobility of such women, who are prone to rest. Constipation leads to increased decomposition of intestinal contents, development of gases, and further increase in abdominal size. The most serious phenomenon is the appearance of toxic symptoms and edema. In some cases, the latter occur on the basis of blood stagnation in the lower extremities; more often they are the result of changes in the walls of blood vessels. In the first months of pregnancy, more frequent urination is due to the sharp increase in the size of the uterus and compression of the bladder. Kidney function is often disturbed: decreased urine output, appearance of protein, and finally formed elements. Then the symptoms of toxemia increase, which can take on all the characteristic symptoms of eclampsia: decreased daily urine output, increased edema, high blood pressure, headaches, pain in the epigastric region, spasmodic contractions of individual muscle fibers, visual disturbances; ultimately the condition can end in eclamptic convulsions. The main complicated forms of multiple pregnancy are as follows: 1) excessive accumulation of amniotic fluid-hydramnion (e.g., in the Clinical Obstetric-Gynecological Institute of the People's Commissariat of Health, it was observed in 6% instead of 0.8% in singleton pregnancy). Mangiagalli found it even in 42% of cases of multiple pregnancy. It is especially common in monozygotic twins. 2) Marked increase in placenta previa and associated bleeding during pregnancy (3-10 times more frequently-State Obstetric-Gynecological Institute of the People's Commissariat of Health). In monozygotic twins, the increased weight of the egg, which descends more quickly, may also be of importance. 3) Very frequent phenomena of nephropathies, eclampsia, and eclampsia. The latter is noted by most authors. Summarizing the material of Strassmann and the Clinical Obstetric-Gynecological Institute, we get for 1,076 multiple pregnancies and births 54 cases of eclampsia, i.e., 5%, while the overall frequency there was 1.5%. It should be noted that mortality from eclampsia in multiple pregnancy significantly increases. Both of these are quite explainable by modern views on the origin of eclampsia and the state of the reticulo-endothelial system during pregnancy. 4) A large number of underdevelopment and malformations in fetuses, especially in monozygotic twins, is easily explainable by imperfect division of the egg, as well as the imperfection of the blood supply from the placenta. The latter explains the frequent death of one of the twins and (if this occurs in the early period of pregnancy) the formation of the so-called 'fetus papyraceus'. 5) Frequent premature births (approximately 60%), which are the result of significant stretching of the uterus and the above-mentioned complications. 6) Frequency of abnormal positions and presentations. 7) Pregnancy toxemias, dermatoses, salivation, jaundice, etc., are more frequently observed. Naturally, all this, as well as many complications during childbirth, make the prognosis of multiple pregnancy serious. (See items 6 and 7 in more detail in Multiple Births.) The mentioned complications are even more frequently observed in pregnancies with a larger number of fetuses. The diagnosis of twins is not always easy. The main signs of multiple pregnancy are as follows: 1) determination of three large parts in the uterus; 2) determination of two identical large parts.

Mixtures with uterine fibromyomas are possible, less frequently with tumors of the appendages. Fibromyomas do not change their position; are often of a different shape; causing uterine contraction, the head of the fetus is not determined at all or is determined unclearly, while the tumor of the uterus (or appendages) is determined as before. Some note that *with pressure on the head of the fetus, the fetal pulse slows down; 3) determination of different frequencies of fetal heart rate, performed simultaneously by two observers, if the difference is at least 10 beats per minute: counting at different times has less probative value, since the fetal heart rate changes under the influence of its movements; a certain correction will be the repetition of the observation several times and 4) X-ray. These four signs have decisive force. Less importance is given to 5) a large uterus with a small fetus and without hy-dramnion; 6) a uterus with a groove (should not be confused with uterus arcuatus or bicornis); 7) the measurement according to Ahlfeld or Ahlfeld-Baldin exceeds 30 cm. During childbirth, new signs appear. The diagnosis is often complicated by a large amount of fat, swelling of the abdominal walls, significant accumulation of amniotic fluid, or the position of the fetus one after another, when the posterior fetus escapes palpation. -Prevention in the case of established M. b. should be carried out »even more deeply, and special attention should be paid to the most minimal toxemic manifestations.