Late Fetal Mortality Research Articles

Male and female components of perinatal mortality: International trends, 1901–63

Abstract Analysis of vital data from five West European countries indicates that there has been a decline in the relative male risk and the sex ratio of late fetal mortality during the period 1901–1963. However, this decline is largely compensated for by an increase in the relative male risk and sex ratio of early neonatal mortality. As a result, no clear and consistent trend in the relative male risk or sex ratio of perinatal mortality can be detected. It is suggested that improvements in obstetric practice or in registration effectiveness may be responsible for the phenomena noted. Whatever the explanation, the findings illustrate the dangers of reifying registration definitions in the analysis of vital events.

Determinants of Sex Proportions in Man, with Consideration of the Evidence Concerning a Contribution from X-linked Mutations to Intrauterine Death

Literature and data from experiments on sex proportions and factors which may influence sex proportions are reviewed. Social and demographic factors relationships between stillbirth rates and sex ratios in utero mortality by sex and shifts in stillbirth ratios with falling stillbirth rates are discussed. Data from animal studies are presented on mutation rates gene frequencies and selective disadvantages related to x-linked mutations which reduce chances of survival in utero. A large number of assumptions are necessary to make any estimate of the supposed effects of x-linked mutations to late fetal mortality. The author doubts that it is possible to measure any component of male mortality in utero attributable to such mutations.

World Health Organization Annual Epidemiological and Vital Statistics

This is the 8th annual volume of vital and health statistics published by the World Health Organization. The report is divided into three main parts: first, vital statistics; second, statistics of cases and deaths from notifiable diseases; and third, statistics of health personnel, hospital establishments and vaccinations. In all three parts the statistics are given for the individual countries of the world for which figures are available. There are two indexes, by country and by subject.Part I includes population figures by sex and age. These figures are less detailed than those given in the Demographic Year Book published by the United Nations but are adequate for the interpretations of the present report. The data presented include natality, general mortality, infant and neonatal mortality, late fetal mortality, and natural increase. Numbers as well as rates are given, by cause of death, sex, and age. A greater detail about malignant deaths is given than in earlier reports.

Longitudinal studies of pregnancy on the Island of Kauai, Territory of Hawaii: I. Analysis of previous reproductive history

This paper provides an analysis of the previous reproductive histories of all the women on the Island of Kauai, Territory of Hawaii, who had experienced at least one pregnancy. The data for the study were obtained from all women of childbearing age taken as part of a complete enumeration of the population of the island made in conjunction with a longitudinal study which is in progress. The data have been tested for all needed indices and found reliable when obtained from women who were less than 50 years of age. Consequently the analysis is based on the information obtained from this group of women. The following findings are recorded: 1.1. The results confirm other studies on the relatively high incidence of early fetal deaths. There were more than twice as many early as late fetal deaths.2.2. The factors of order of pregnancy and age of the mother have some-what different effects on the early fetal death rate, the late fetal and neonatal mortality rates, and the postneonatal death rates. The effect of order of pregnancy is stronger for the older infants, while the age of the mother exerts a greater influence on fetal mortality.3.3. The interval between the termination of one pregnancy and the beginning of the next is associated with the survival of the offspring. The early fetal, late fetal, and neonatal mortality rates are high when the interval is short. They are at a minimum when the interval is around 2 years, and increase for longer intervals. On the other hand, postneonatal and childhood mortality rates are lower when the interval between pregnancies is longer.4.4. There is a strong association between the outcome of one pregnancy and that of the immediately preceding one. When a mother suffers a loss in the form of a fetal or infant death, the chances are increased that she will sustain a subsequent loss. This association is specific for type of loss, i.e., when a woman has had an early fetal death she is more likely to have a similar accident in a subsequent pregnancy, but her chance of sustaining a late fetal loss is no greater than when the previous pregnancy resulted in a surviving infant. Similarly, if a women has sustained a previous loss through a late fetal death the likelihood of a similar accident is increased but the chance for an early fetal death in a subsequent pregnancy is not increased.5.5. These findings are discussed in terms of possible etiological and causative factors. It is suggested that the three types of losses, (1) early fetal, (2) late fetal and neonatal, and (3) postneonatal mortality, represent three distinct manifestations of reproductive wastage, and are influenced by biological and environmental factors to different degrees and in different ways. Early fetal deaths are probably influenced most by unfavorable biological factors. Environmental factors become increasingly important as age increases.6.6. The type of retrospective study described was found to be reliable and should provide a valuable method for further studies of reproductive wastage.7.7. The specific repetitive character of reproductive wastage points to the value of complete and accurate reproductive histories as a means of increasing data available for study and for providing information of immediate value in the provision of care to pregnant women.

Neonatal mortality by order of birth and age of parents.

A study of all infants born in New York State, exclusive of New York City, in 1936 has been made with the intent of investigating the effects of order of birth and age of paretns of neonatal mortality. The study revealed these results. 1) Of the 82,140 infants, 2563 (31.2/1000 livebirths) died before 1 month of age. 2) Firstborn infants, as well as those of higher birth orders, were found to have a considerably higher mortality than the intermediary births. The rate for 1st births was 32.1; for 2nd births it was 26.0. It rose gradually for births of orders 2, 3, and 4, and sharply beginning with 5th births. The rate for infants of order 10 and over was 55.2, more than twice the rate for 2nd births. 3) More than 1/2 of the neonatal deaths (54%) were found to occur among infants born prematurely, while less than 3% of the surviving infants for the 1st month of life were premature. The frequency of prematurity was 42.9/1000 livebirths. 4) The mortality of premature births was extremely high (389.2), and it rose with order of birth. The rate was a minimum for 1st births (329.4) and rose to a rate of 644.4 for infants of order 10 and over. However, the frequency of premature births/1000 livebirths started high for 1st births (49.3), was a minimum for 5th births (36.0), and increased thereafter. 5) The neonatal mortality of infants carried to fullterm was only 15.2/1000 livebirths. Thus, the rate for prematurely born infants was 25 times as high as the rate for fullterm infants. The handicapping of the 1st born is very marked for the latter. The rate for fullterm 1st births was 44% higher than the rate of 2nd births. 6) The neonatal mortality for male infants was consideralby higher for than female infants for every order of birth. 7) Premature births were more frequent in urban communities than in the rural part of the state. However, the mortality among the premature was higher in the rural areas thanin the cities. 8) When stillbirths were added to neonatal deaths, the total loss (late fetal and neonatal mortality) presented the same variation by birth order as neonatal mortality. The rate for the total loss was 58.4 and the frequency of prematurity was 55.5/1000 total births. 9) Neonatal mortality of infants born to very young mothers and to older mothers is considerably higher than that of infants born to mothers ages 20-30. The lowest rate was recorded for mothers ages 27-28. 10) The same trend of mortaltiy by age of mother was observed in practically every order of birth. It started high for young mothers of every birth order, dropped gradually to a minimum, and then rose to very high rates for old mothers. Neonatal mortality seems to be independently correlated with the 2 factors of birth order and maternal age.