A follow-up study of first trimester induced abortions at hospitals and family planning clinics in Sichuan province, China.

Four-thousand women aged 18-40 underwent an early induced abortion at hospitals and family planning clinics in six counties in Sichuan province, China, between 1 July 1990 and 30 June 1991. The subjects were followed-up three times, on days 15, 90 and 180 after the operation. Information was obtained about their age, parity, contraceptive use, social behaviors, and gynecological and psychological characteristics before and after the abortion. The results indicate that induced abortion is safe when provided by medically trained personnel in health facilities such as hospitals or clinics. Depressive symptomatology was assessed by the CES-D and SCL-90 scales. The depressive symptoms declined over time. A substantial proportion of the abortions were to unmarried women or resulted from non-use of contraception or contraceptive failure, implying that the incidence of unintended pregnancies and induced abortions could be reduced by more effective and accessible contraception.

Induced abortion among unmarried women in Sichuan province, China.

This report describes the social and demographic characteristics of 457 unmarried women who underwent a first trimester induced abortion at hospitals and family planning clinics in Sichuan province, China. The data show a very low level of medical complications. However, improved access to contraception for unmarried women is needed in order to reduce the incidence of unintended pregnancies and induced abortion.

PIP: A prospective study conducted in China's Sichuan Province in 1990-91 revealed a high incidence of induced abortion among young, unmarried women and a consequent need to improve this group's access to contraceptive services. Included in the survey were the 457 unmarried women undergoing first-trimester abortion during the study period in six Sichuan counties selected for their diversity in terms of demographic factors and abortion facilities. 129 women (28.2%) were under 20 years old; 296 (64.8%) were 20-24 years of age. 89.8% had a primary or middle school education; 83.8% were from rural areas and 76.6% were employed as farmers. 423 women (92.6%) were not using any form of contraception when the pregnancy occurred and 260 (35%) reported at least one previous abortion. Most abortions were performed by specially trained family planning staff with at least three years of experience in abortion provision. There were no cases of cervical or uterine trauma, retained tissue, or uterine perforation and no significant post-abortal complications. These unmarried abortion patients appeared to be relying on abortion as a family planning method rather than as a back-up method in case of contraceptive failure. It is essential that the Chinese Government's campaign to encourage young people to postpone marriage until their early twenties is accompanied by education on contraception and greater access to contraceptive supplies.

Correlations between frequencies of kin.

Recent years have seen the development of formal and microsimulation models of the structure and dynamics of kin networks. These models generally assume uncorrelated fertility within and across generations. Several sets of real data, however, show positive correlations between the frequencies of various categories of kin. This paper uses formal models to calculate the correlations that will exist between certain categories of kin even if mothers and daughters have independent fertility. Mechanisms by which fertility might be transmitted from mothers to their daughters are considered and the implications for kin correlations are evaluated.

Statistical methods to adjust for date and age misreporting to improve estimates of vital rates in Pakistan.

Misreporting of dates and ages poses serious difficulties for the estimation of the age distribution and birth and death rates in many developing countries. The pervasiveness of these problems is illustrated with data from a well-designed on-going survey in Pakistan, the Pakistan Demographic Survey. Methods for reconciling discrepancies, based on the assumptions of constant misreporting and survivorship patterns, are presented. The reasoning behind these methods could be applied much more generally. Research into the cultural interpretations of age and dates, and the nature of possible biases, is called for.

Evidence for and against the emergence of family size norms in Pakistan.

PIP: Responses to questions on desired and ideal family size from the 1984-1985 Pakistan Contraceptive Prevalence Survey are analyzed for the presence of norms regarding family size. Factors analyzed include region, residence characteristics, educational status, wife's labor force participation, husband's occupation, and wife's age and parity. Pakistani culture and its level of fatalism concerning family size are also considered.^ieng

Measuring change and continuity in parity distributions.

Procedures are developed to allocate the change in mean fertility to the change in specific parities or groups of parities. One procedure uses the proportion at each parity and another uses parity progression ratios. Both are based on the delta method for approximating change in a function of several variables. Drawing on an analogy to survival in a life table, the relational logit model is applied to parity progression. This method allows several parity distributions to be synthesized and to have differences summarized with two parameters. The three procedures are applied to successive cohorts of white U.S. women who completed their childbearing between 1920 and 1980.

Fertility in Pakistan during the 1970s.

PIP: Evidence of trends in fertility and related variables in Pakistan during the 1970s is analyzed using data from 2 comparable surveys: the 1975 Pakistan Fertility Survey (PFS) and the 1979-80 Population, Labor Force and Migration Survey (PLM). Both suggest that fertility was fairly constant, with a total fertility rate around 7.0 until the 5-year period preceding the surveys (1970-74 and 1975-79, respectively), during which it declined abruptly. The apparent date of the decline is thus conflicting. The evidence of recent decline in each survey is likely to be spurious, the result of systematic distortions in the reporting of dates. The present research finds evidence that fertility as measured by age-specific and marital age-specific rates did not change in Pakistan during the 1970s, except for a decline in age group 15-19 as a result of delayed marriage. An analysis of levels and trends in selected components of fertility indicates that all subgroups, except literate women, show a rise in the average age at marriage of the order of 1/2 a year or so. Differentials between subgroups are in the expected direction, with literate women marrying later than illiterate ones and women in urban areas marrying later than those in rural areas. There is no notable change in the % of children being breastfed; however, the average duration of breastfeeding shows a non-trivial decline in all subgroups. Nonetheless prolonged breastfeeding is still the general practice. Current use of contraception at the time of the 2 surveys actually declined by 1980, while knowledge, reported ever-use, and fertility preferences all moved in a pronatalist direction. The lessons of this study are primarily methodological. In particular, the analysis of fertility change in the future in Pakistan will require either more reliable reporting of birth histories, or the continued piecing together of 2 or more surveys.^ieng

Population estimates from longitudinal records in otherwise data-deficient settings.

Existing methods for estimating population parameters in settings of data deficiency do not provide techniques for analysis of commonly available longitudinal data. In setting where complete population data is unavailable, longitudinal data recorded for only a subset of the total population are often available (e.g., event registers, genealogies). In this article we present and evaluate models which derive population parameters for the population subgroup underlying such longitudinal data. Using the distribution of individual times until first recorded event within a measurement interval, population parameters are estimated which provide basic denominator data for analyzing event occurrence. The models which we derive are especially suited to records which may include migration and population growth trends. The use of the models is demonstrated and evaluated through an application to genealogical records for a nineteenth-century population. Possible extensions of these models and their major limitations are also discussed.

The eventual frequencies of kin in a stable population.

Associated with every real birth cohort of women is a set of probabilities [fk] of eventually having k daughters. With a variant of stable population theory, these probabilities are used to generate the entire probability distributions, as well as all moments, for all categories of skin who are female and female-related. With additional assumptions, a full two-sex model for all kin also is given. The two-sex model is applied to a cohort of U.S. women born in the mid-twentieth century, suggesting plausible frequencies of kin in a stationary population.

Estimating fertility trends from retrospective birth histories: Sensitivity to imputation of missing dates.

Abstract In the birth history section of the Core Questionnaire adopted by the countries participating in the World Fertility Survey a question on the date of birth of each child born to the respondent is asked. When the woman cannot provide a date, as is often the case in many developing countries, she is asked how many 'years ago' the birth occurred. If the default is used, the month and year of the birth is imputed by a computer program: However, there can be two plausible interpretations of the 'years ago' response: as completed years, the demographer's usual definition of age, or as rounded years. In this paper, data from the WFS Survey in Bangladesh are used to determine the sensitivity of recent fertility estimates to the interpretation of 'years ago'. It is found that if the woman meant rounded years, but completed years were assumed for imputation, the resulting evidence of a recent decline could be either exaggerated or false. The results have implications for other surveys in which the 'years ago' response is not an explicit option.

A vital statistics-based procedure for estimating conception rates.

A method for estimating conception rates, using vital statistics data, is developed and applied to data on five-year age groups of California women for 1971. The approach is deterministic and allocates total exposure time to the known pregnancy outcomes of live birth, spontaneous abortion, and induced abortion. The population at risk is defined to exclude women who are known to be sterile or sexually inactive. Early fetal loss, premarital conception, and contraceptive use are taken into account. Estimates are made of the fecundability which would obtain if no contraception were used.

Path analysis: application in an epidemiological study of echinococcosis in New Zealand.

The method of path analysis is described in detail. Application of this analyogical systems is demonstrated using data from an epidemiological study of echinococcosis in New Zealand. The results identified the major causal pathways determining Echinococcus granulosus prevalence in dogs, based on multiple regression analysis of a linear causal model constructed from prior biological and epidemiological knowledge. Only ethnic and sheep husbandry variables had important direct effect on prevalence in the North Island of New Zealand, with some climate factors (maximum temperature and relative humidity) and soil porosity acting indirectly through animal husbandry practices. It is suggested that path analysis, by permitting interaction between epidemiological theory and statistical analysis, provides a valuable additional tool to epidemiologists for the study of causal relationships among variables in multivariates systems.

Effectiveness of abortion as birth control.

PIP: Several models used to study the effectiveness of abortion in population limitation are examined. The Keyfitz model, based on the probability that an individual woman will conceive in a given month, is extended and public implications of legal abortions are discussed. A model more appropriate for a population of women rather than a single woman can be developed by relating the probability of conception and the sterile intervals to the number of birth and the number of women in the population. The effectiveness of abortion as a birth control method is studied using this model and includes: 1) abortion effectiveness combined with efficient contraception (95% effective); 2) the sensitivity of abortion to gestation when a contraceptive of lower efficiency is used; 3) these effects modified for prolonged lactation; 4) the effect of changing the monthly probability of conception and the monthly efficiency of contraception. Abortion later in pregnancy is advantageous when efficient contraception is absent. The effectiveness of abortion to gestation is approximately the same whether lactation is included or absent, although abortion is more effective at all gestations and for all contraceptives efficiencies in the absence of lactation. The sensitivity of the effectiveness of abortion to the probability of conception decreases as monthly effectiveness of contraception increases. The probability of conception and the monthly effectiveness of contraception are difficult parameters to measure in the population. The effect of abortion averaged over the entire population at risk of pregnancy is different from its effect on certain subgroups. For U.S. females the probability of conception may be between .06 and .16, and from the model it is indicated that the effectiveness of abortion would be from 1 to 1.13 abortions per live birth. The application of the model suggests that the expenditures for abortion services in this population are a reasonable investment, although investment for efficient contraception is also suggested.^ieng