A model to estimate births averted due to IUCDs and sterilizations

The computation of births averted due to a specific family planning programme requires special treatment instead of application of the usual population projection technique using conventional fertility rates. The reason for this is that adopters of a family planning method are a selective group from the general population with respect to a number of demographic and biological characteristics, including the initial susceptibility status at the time of adoption. In the present paper a matrix of annual birth probabilities specific to age at adoption of a method and duration since adoption is obtained. One matrix is presented for adopters of IUCD, another for salpingectomy, and a third for vasectomy. These matrices are used to obtain estimates of births averted for India due to IUCDs and sterilizations performed during 1956–69. The results are compared with those that could have been obtained by using the usual age-specific marital fertility rates under identical conditions, except for initial susceptibility. The entire work is programmed on a high speed electronic computer.     

Legal abortion and fertility in Maryland, 1960–1971

In the brief period between 1967 and 1971 about one-third of the state legislatures passed abortion reform bills, and in states such as Maryland the number of legal abortions soared. Maryland with its good reporting system for legal abortions, as well as its demographic representativeness, appears to offer an ideal "test situation" for assessing the impact on fertility of the new liberalization. Data on live births and reported induced abortions to residents of the state have been compiled and analyzed in an effort to interpret the recent changes in birth rates. Variables examined include maternal age, birth order, race, and legitimacy.Since 1968, Maryland, along with higher than national average abortion ratios, has experienced a rate of decline in fertility greater than that for the nation. In addition, most of the age and parity groups with high abortion ratios show fertility declines greater than those for groups not using abortion as extensively, Nevertheless, because a number of different factors simultaneously influence fertility, it is hazardous to make accurate cause-and-effect statements on the relationship of any single one of these to the observed change.     

Role of the social and cultural factors in human fertility in India

During the 1940s and 1950s in India, a relatively low level of fertility of 6–8 children per woman of unbroken marriage is implicated by the social and cultural factors; the fertility was probably depressed by 15–20 percent. An appraisal of the trends over the last 2–3 decades of the pertinent variables—age at marriage (an early and almost universal marriage); the widow remarriage rates; the induced abortion rate; postpartum infecundability (breastfeeding) and postpartum abstinence; the son preference; and the other sexual attitudes and taboos—suggests that during the late 1970s and early 1980s, the fertility enhancing and retarding forces were offsetting each other. But, over the next two decades, the variables responsible for enhancing the fertility level will play a more dominant role than the corresponding fertility-reducing factors. However, the role of induced abortion remains somewhat unclear. For any significant reductions in the national crude birth rate in India during the 1990s, the family planning efforts will have to be considerably accelerated.     

Statistical modeling of selected aspects of the childbearing process with application to world fertility survey countries∗

The childbearing process should be monitored in developing countries experiencing high population growth rates and high levels of maternal and infant mortality. A mathematical model for estimation of certain aspects of the childbearing process, which requires only data on age‐specific fertility rates, is developed. Synthetic maternal childbearing indices, namely, mean ages at first and last birth, length of reproductive life span, inter‐birth spacing, and proportion of childless women, in addition to the well‐known mean age at childbearing, for the WFS countries are obtained using the proposed model. The indices are free from age truncation effects, and, under certain assumptions, provide information about a cohort's completed fertility before the women stop reproducing. The effects of women's residence and education on fertility are also examined.     

The construction of the fertility model of variable parity from family planning practice]

Understanding the changing patterns of age specific fertility under the planning system is essential for building a fertility model which reflects birth control policy implementation in China. In building a Parity Variable Fertility Model, 4 basic elements are to be considered: 1) psychosocial, and physiological variables, 2) patterns of the total fertility rate and age-specific fertility rate, 3) socioeconomic development, and 4) distribution of parity-specific fertility. THe natural fertility of women is 17, calculated from a 309-years childbearing period, with 17% of non-susceptible time. In China, about 86% of natural fertility is suppressed by various factors. In this model, the following variables are included: 1) The first marriage ratio, which is the proportion of women in each age group which enters into a first marriage. The range and spread of this ratio is closely associated with the first birth. 2) The first birth ratio, which is the proportion of a marriage cohort to have a first birth each year. 3) the birth interval, which determines the distribution of second births. 4) Regulation coefficient B, which represents birth control regulations which approximately determine the number of second-parity or higher order births. The difference between the fertility level generated from the Parity Variable Fertility Model and reality depends on the implementation of birth control program, the assumptions on regulation coefficients, and changes in social and cultural factors. The model is easy to use, especially for areas where the marriage and fertility records of women of child-bearing are well kept.     

A dynamic model of the reproductive process

Summary A dynamic deterministic model of the reproductive process is presented. The model describes and analyses the effect of intermediate fertility variables on fertility. The intermediate fertility variables which are the inputs to the model, include the duration of post-partum amenorrhea, fecundability, incidence of spontaneous and induced abortion, contraceptive use and effectiveness, the distribution of age at first marriage and the age specific risks of marital disruption and remarriage. To test the validity of this model, it is fitted to data obtained from reproductive histories of 512 marriages occurring during the first half of the eighteenth century in Canada.     

Eastern Europe: pronatalist policies and private behavior

Fertility trends in the 9 Eastern European socialist countries (Albania, Bulgaria, Czechoslovakia, German Democratic Republic, Hungary, Poland, Romania, USSR, Yugoslavia) are reviewed. Official policy in all these countries but Yugoslavia is explicitly pronatalist to varying degrees. Attention is directed to the following areas: similarities and differences; fertility trends (historical trends, post World War 2 trends, and family size); abortion trends (abortion legislation history, current legislation, abortion data, impact on birth rates, abortion seekers, health risks, and psychological aftereffects); contraceptive availability and practice; pronatal economic incentives (impact on fertility); women's position; and marriage, divorce, and sexual attitudes. The fact that fertility was generally higher in the Eastern European socialist countries than in Western Europe in the mid-1970s is credited to pronatalist measures undertaken when fertility fell or threatened to fall below replacement level (2.1 births/woman) after abortion was liberalized in all countries but Albania, following the lead of the USSR in 1955. Fertility increased where access to abortion was again restricted (mildly in Bulgaria, Czechoslovakia, and Hungary at various times, and severely in Romania in 1966) and/or economic incentives such as birth grants, paid maternity leave, family and child care allowances, and low interest loans to newlyweds were substantially increased (Bulgaria, Czechoslovakia, Hungary, and Poland to some extent, in the late 1960s and early 1970s, and the German Democratic Republic in 1976). Subsequent declines in Bulgaria, Czechoslovakia, Hungary, and Romania suggest that policy induced increases in fertility are short-lived. Couples respond to abortion restrictions by practicing more efficient contraception or resorting to illegal abortion. It is evident that the region's low birth rate is realized mainly with abortion, for withdrawal remains the primary contraceptive method in all countries but Hungary and the German Democratic Republic. It seems that cash incentives have advanced the timing of 1st and 2nd births without substantially increasing the 3rd births required to keep national fertility above replacement level. Demographic factors alone will most likely keep birth rates low in several Eastern European countries during the 1980s and the 1990s. Due to the low birth rates in the 1960s, there will be fewer women in the prime childbearing ages of 20-29 in at least Poland, Czechoslovakia, Bulgaria, and Hungary. It becomes clear that policy efforts to influence private reproductive behavior can only be moderately successful if the living conditions are such that women are determined not to have more than 1 or 2 children.     

An analysis of the fertility transition in developing countries]

Most developing countries are in the demographic stage of early mortality, high birth rates and high rates of natural population increase. A characteristic of developing countries is that after World War ii, particularly since the 1960s fertility rates are on the decline, even though they still remain high. The fertility rate of developed countries fell from a 1950 rate of 22.9/1000 to 15/1000 in 1982, a decrease of 34.5%, whereas the fertility rate of developing countries hovered around 43/1000 between 1930-1950, 40.6/1000 during the 1960s and 33/1000 in 1982. Between 1950 and 1982 there was a decrease of 24.8%. But the main reason for this decrease is the decline in the last 20 years of the fertility rates of China and India, whose rates fell 34.9% from 1960-1980. Changes in fertility rates are influenced by the age structure of a country, as seen in the changing age structure of developing countries from 1960-80. For example, an increase in fertility rates was 1 consequence of an increase in the number of fertile women aged 15-45 from 42.6% in 1960 to 44.4% in 1980. Nevertheless, there exists some sort of birth control, whether conscious or subconscious, because the number of births per fertile woman is 3-4 fewer than the 14-15 children a woman can theoretically bear. The reason for changes in fertility rates in developing countries can be traced to marriage and family customs, and even more important, to social and economic factors. For example, Asian, African and Latin American cultures tend to support early marriages. When the fertility rates of developed and developing countries are looked at for a comparable period, then the rate of decrease for developing countries is slower than developed countries. But, if the comparison is made for a transitional period (i.e., industrialization), then the rate of decrease for developing countries is faster than for developed countries. Currently there are 25 developing countries that have attained a fertility rate of 25/1000 or lower, and 52 developing countries with a rate of 35/1000.     

A method for calculating rates of induced abortion

Accurate measurement of induced abortion is necessary for understanding the fertility dynamics of a population and for making projections about the future. Changes in abortion rates can amplify or dampen the impact of changes in contraception. This paper presents a methodology for calculating marital induced abortion rates from observed marital fertility and contraceptive prevalence and for modeling the impact of substituting contraception for abortion on future fertility. The methodology is validated against observed abortion complications in three populations, and the impact of substituting contraception for abortion on expected fertility is demonstrated.     

Statistical modeling of selected aspects of the childbearing process with application to World Fertility Survey countries

"A mathematical model for estimation of certain aspects of the childbearing process, which requires only data on age-specific fertility rates, is developed. Synthetic maternal childbearing indices, namely, mean ages at first and last birth, length of reproductive life span, inter-birth spacing, and proportion of childless women, in addition to the well-known mean age at childbearing, for the WFS [World Fertility Surveys conducted in developing] countries are obtained using the proposed model. The indices are free from age truncation effects, and, under certain assumptions, provide information about a cohort's completed fertility before the women stop reproducing. The effects of women's residence and education on fertility are also examined." (SUMMARY IN FRE)     

A comparison between current Indian fertility and late nineteenth-century Swedish and Finnish fertility

Abstract The paper aims to probe causes of the current high level of the crude birth rate in India. This is accomplished by comparing the current Indian fertility level with that of Sweden and Finland during the last quarter of the nineteenth century. By utilizing marital distribution, age distribution and age-specific marital fertility rates of the three countries, the basic demographic causes of high fertility in India can be established. In the second part, the factors causing age-specific marital fertility rates in India to be lower than nineteenth-century Sweden and Finland are discussed. This is done by comparing the levels of the followingsix variables, operating within marriage, between Indian and Scandinavian cultures: (1) Abstinence - voluntary and involuntary, (2) Frequency of coitus, (3) Incidence of sterility - primary and secondary, (4) Contraception and sterilization, (5) Incidence of foetal mortality and (6) Incidence of induced abortions.     

Vital rates in India 1961-71 estimated from 1971 census data

Abstract In the last decade the increase in the population of India, while, of course, very large, was smaller than predicted by official forecasts. With the use of recent census and sample registration data - in the absence of age-specific rates and adequate vital statistics - this paper provides estimates of fertility and mortality through the reverse-survival and forward-projection methods. Birth rates are estimated as 40·5-42, death rates as 18-20, and life expectancy at birth as 45-46 years. Mortality decline had been smaller than forecast but more than during any comparable period in the past, even though current mortality levels, particularly infant mortality, are still high. Males continue to have a longer life expectation than females, with a difference that has widened in the past decade. The decline of between seven and ten per cent in the crude birth rate is largely due to changes in marital fertility and to some extent to changes in age and marital composition. Because of greater decline in death rates than birth rates, the 1961-71 decade shows a higher rate of population growth than previous periods.     

A decomposition of trends in the nonmarital fertility ratios of blacks and whites in the united states, 1960–1992*

We use a method of standardization and decomposition developed by Das Gupta to update Smith and Cutright’s analysis of demographic factors responsible for increases in the nonmarital fertility ratio (illegitimacy ratio) among blacks and whites in the United States. We create standardized rates for each year between 1960 and 1992, and consistent, exhaustive decompositions of the nonmarital fertility ratio for any interval during this period in terms of four components: (1) the age distribution of women of reproductive age, (2) the proportion of women unmarried at each age, (3) the age-specific birth rates of married women, and (4) the age-specific birth rates of unmarried women. Nonmarital fertility ratios are much higher among blacks than among whites, but both increased monotonically from 1960 to 1992. During the last 10 years, each increased by nearly 10 percentage points. Increases in the proportion of women not married, at all ages, account for the preponderance of the increase in black nonmarital fertility ratios. Increasing rates of unmarried childbearing, however, have played a role during the most recent decade (1983–1992). For whites, from 1960 until 1975, declines in marital fertility were most important in producing increases in the proportion of children born out of wedlock. Since then, these proportions have increased primarily because of increases in unmarried women s birth rates, and secondarily because of declines in the proportion of women who are married. These trends are consistent with arguments that emphasize declining economic incentives to marry and reduced access to, and acceptability of, abortion.     

Japan's fertility: effects of contraception and induced abortion after World War II

This report studies the effects of contraception and abortion on crude birth rate (CBR) and total fertility rate (TFR) in Japan from 1947-1980. The CBR declined from 34.3 in 1947 to 17.3 in 1957, and the TFR from 4.5 to 2.0 in the same period. Both stabilized (CBR in the range of 17.0 to 19.0 and TFR at 2.0 to 2.1) between 1957 and 1973. This dramatic decline in fertility was initiated under the serious socioeconomic difficulties of post-World War II Japan. At the onset of the postwar fertility decline, fertility within marriage was controlled most strongly by induced abortion, and to a lesser extent, lactation and contraception. During the period of stable low fertility (1960-1980) the effect of abortion decreased and the effect of contraception increased. KAP surveys show that in the late 1970's more than 75% of contraceptive users in Japan employed the condom, while condom use in other Asian countries is generally very low. A shift from traditional to modern methods of contraception is unlikely to alter the already low level of fertility in Japan but would have considerable social, medical, and economic impact.     

Constructing fertility tables for Soviet populations

Because the 1970 Soviet Union census does not provide information on the age structure of men and women separately by sex and according to their ethnic affiliation, the 1959 USSR census data serve as the basis to infer knowledge about ethnic fertility. The model takes into account (1) the total number of births in 1960, estimated from the child-woman ratio in 1959, (2) the age structure of women in 1959, and (3) the assumed pattern of age-specific birth rates structured in terms of the modal age at childbearing and the length of the fertility age span. The results show that Ukrainians among the Slav populations ranked as the lowest with 2.07 children born per woman. Their total fertility contrasts with that of Kazakhs native to Central Asia, who reportedly according to Soviet sources had 7.46 children per woman in 1958-1959, and whose estimated rate is around 8.59 children. Extreme variations appear in the estimates of fertility among nationalities of the Caucasus region, Volga Basin, and to a lesser degree in Siberia. Official Soviet calculations of crude birth rates and age-specific rates for 15 Union Republics in 1967-1968 are transcribed and compared with the estimates for nationalities in 1959-1960. The same theoretical model used to generate the Soviet rates may be adapted under different assumptions to non-Soviet populations in other situations where the data are scanty or incomplete.     

A reformulation of the two-sex problem

The ability of classical stable population theory to determine the equilibrium growth rate and age structure of a population from its vital rates in a single period depends on assuming that the observed maternity rates are equilibrium rates. This paper resolves the two-sex problem by replacing the fixed, age-specific fertility schedule of classical stable population theory by two basic relationships: a “birth matrix” and a “mating rule.” Placing certain restrictions on the birth matrix and the mating rule (BMMR), I establish that under certain plausible conditions, the BMMR model solves the two-sex problem by allowing matings and births to adjust to changes in population structure. The BMMR model thus provides an equilibrating mechanism in place of a fixed maternity schedule of classical stable population theory.     

A model of the age patterns of births by parity in natural fertility populations

This research develops a convolution model to express the age patterns of fertility at each birth order in natural fertility populations in terms of six parameters, directly representing the proximate determinants of fertility, and a series of parity level indicators. The parity level indicators at each birth order are simply the proportions of women in a cohort who will eventually have births at each birth order it the age‐related fecundity decline is controlled. The Coale‐McNeil nuptiality model is adopted to represent the age pattern of first marriage rates and the natural fertility schedule employed in the Coale‐Trussell fertility model is incorporated to adjust age effects. The fast Fourier transform is used in solving the model numerically. It proves that the model is able to provide excellent fits to fertility for rural Chinese women in the 1950s.     

Interstate variations in teenage fertility

The extremely wide variation among states in adolescent childbearing is examined using indicators that represent high or low modernity, i.e., percent urban, percent fundamentalism, percent black, and region (South-non-South); the intermediate variables of factors affecting exposure to intercourse (percent married females 15 to 19); and the deliberate fertility control factor of induced abortion (the state abortion-to-live birth ratio). Eighty-six percent of the variance among states in the 1974 teenage fertility rates (females 15 to 19) is explained, with region the most powerful single indicator of fertility, followed by percent married and state abortion ratio.     

Estimation of demographic measures for India, 1881-1961, based on census age distributions

Abstract India is one of the very few developing countries which have a relatively long history of population censuses. The first census was taken in 1872, the second in 1881 and since then there has been a census every ten years, the latest in 1971. Yet the registration of births and deaths in India, even at the present time, is too inadequate to be of much help in estimating fertility and mortality conditions in the country. From time to time Indian census actuaries have indirectly constructed life tables by comparing one census age distribution with the preceding one. Official life tables are available for all the decades from 1872-1881 to 1951-1961, except for 1911-1921 and 1931-1941. Kingsley Davis(1) filled in the gap by constructing life tables for the latter two decades. He also estimated the birth and death rates ofIndia for the decades from 1881-1891 to 1931-1941. Estimates of these rates for the following two decades, 1941-1951 and 1951-1961, were made by Indian census actuaries. The birth rates of Davis and the Indian actuaries were obtained basically by the reverse survival method from the age distribution and the computed life table of the population. Coale and Hoover(2), however, estimated the birth and death rates and the life table of the Indian population in 1951 by applying stable population theory. The most recent estimates of the birth rate and death rate for 1963-1964 are based on the results of the National Sample Survey. All these estimates are presented in summary form in Table 1.