Twin pregnancies with one twin blighted

Abstract An attempt has been made to bring together as much information as was available in the literature concerning the maternal history and fetal relations in twin pregnancies in which one twin was born viable at or near term together with a blighted twin which had died in utero prior to the beginning of the seventh month of pregnancy. Two cases of this kind available to the author have been included and used as a basis for an analysis of the cases reported in the literature. One hundred and fifty cases have been used for the presentation of the comparative data. Also data on normal twinning, placentation etc., have been used as supplementary material. Some of the more important results may be briefly summarized as follows: Blighting occurs in the same proportion in monochorial as in dichorial pregnancies; it occurs more often in primiparas when the pregnancy is monochorial. There is greater degree of blighting in dichorial pregnancies when the mother is 30 to 35 years of age or over forty years of age, than at any other time either in dichorial or monochorial pregnancies. There is no sex bias in blighting. Surviving twins are heavier than either of twins of viable twin pregnancies. The viable twin is usually the first born, and is usually presented in the cephalic position. The greatest incidence of blighting is from the third through the fifth month; flattening of the blighted twin is its usual fate, but it may remain well preserved, nonflattened, macerated or mummified. Amniotic fluid is usually lacking in amniotic cavities of fetuses which are flattened and mummified, but fluid of unknown origin may be present around a mummy which is hard. The position of the fetus in the uterus prior to death is suggested as being related to the kind of physical modification which it undergoes. Hydramnios may be a factor in flattening, but it is not the only factor. An uneventful course of pregnancy is the rule rather than the exception. Syphilis occurred in only two reported cases. Detailed histologic study has revealed the remarkable preservation of muscle striations in the heart and voluntary muscle of a 4.9 month fetus papyraceus, which was retained in the uterus with its viable twin until term. Varying degrees of preservation were reported for the placentas. They were practically always necrotic either in part (monochorial), or in whole (dichorial). The incineration method was applied to sections of the placenta of the 4.9 month fetus (Case 1), and it was revealed that calcium deposits were confined to the original sites of the chorionic epithelium, a condition which Schultz-Brauns and Schoenholz hold is evidence for the primary necrosis of the placenta as of maternal origin. Vascular anastomoses in the placentas of monochorial twins have been recorded as occurring in only a few cases of blighted twins, so that it is considered not to be a great factor in the death of one of monochorial twins. Cord complications which could lead to death of the fetus have been recorded in relatively more cases than is characteristic of single pregnancies. The characteristics of the umbilical cord in Case 1 of this paper, show that necrosis progressed from the placenta toward the fetus. Uniformity of recording the characteristics of blighted fetuses is suggested as a valuable aid in extending our knowledge of this condition, since we cannot set up experiments in animals which will parallel the conditions peculiar to human plural gestation.