Longitudinal studies of pregnancy on the Island of Kauai, Territory of Hawaii

Abstract

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.