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Unwanted Fertility


The concept of unwanted births that is now so familiar in population studies has been in use for more than half a century. It plays an important role in the design and analysis of population policy. Early criticism of the concept–on both methodological and measurement grounds–has abated but not disappeared.

The origin of the concept is unclear, but its first systematic quantifiable use seems to have been by Pascal K. Whelpton and Clyde V. Kiser in the 1940s in the Indianapolis Study, formally known as Social and Psychological Factors Affecting Fertility. A classification of fertility planning status was developed in which the category termed "excess fertility" became the prototype for the later designation of unwanted fertility. This measure was further refined and applied in two subsequent U.S. fertility surveys.

Definition and Measurement

The basic idea is deceptively simple: Some births are wanted and some are not. The current professional usage of the concept is more complicated. The term unwanted means that no additional birth as recalled at the time of conception was wanted. In theory, this means that if preferences had prevailed, the birth would never had occurred, a "non-event" of considerable importance for rates of fertility and population growth as well as for the individuals involved. A distinction is drawn between an unwanted and a mistimed birth–the latter being a birth that occurred earlier than preferred but that was nonetheless wanted, although at a later time. Both mistimed and unwanted births are frequently designated collectively as unintended births in contrast to births that were wanted and that occurred approximately at the desired time.

Reports on the planning status of births are based typically on interviews with women in sample surveys and involve memories about events in the past and about feelings that may be complex and highly ambivalent–and affected too by the typically uninvestigated preferences and power of the male partner. Hence there are inevitable questions about the meaning of responses and about the reliability of recall. In recent practice, the question is usually focused on births in the preceding five years but it is still subject to recall problems, especially the understandable tendency to rationalize an unwanted event as wanted. The typical question in the surveys is: "At the time you became pregnant with [name] did you want to become pregnant then, did you want to wait until later, or did you want no more children at all?" Recent evidence, based on reinterviews with women who were asked the same questions about the same births some time later indicates considerable inconsistency in responses–increasing with the duration of recall and biased in the (expected) direction of rationalizing unwanted as wanted births. Thus, it seems reasonable to assume that the level of unwanted fertility in a population based on this approach is underestimated. The magnitude of this underestimate


is unknown but is certainly greater when the births are further back in time.

Wanted Fertility Rate

Another approach to the assessment of unwanted fertility is based on comparing the number of children desired with the number actually born. The now standard question to determine the desired number is: "If you could go back to the time you did not have any children and choose exactly the number of children to have in your whole life, how many would that be?" In order to preserve the current status of the measure, this approach estimates a synthetic Total Wanted Fertility Rate (TWFR) analogous to the familiar standard Total Fertility Rate (TFR) by subtracting from each age-specific component those births occurring in the recent past (usually three or five years) that exceed the total number wanted by the woman. The resulting TWFR is interpreted as the number of births women would have by the end of their childbearing years if at each age they experienced only the number of births wanted in the recent time period. The difference between the TWFR and the TFR is the component representing unwanted births. In Table 1 the results of such calculations for a sample of developing countries are illustrated. The estimates of unwanted fertility based on this procedure tend to be somewhat higher than those based on the first approach of asking about the wanted status directly but the ranking of countries is very similar for the two measures.

The estimates in the table show an average of about 20 percent of births to be unwanted. This provides some sense of the possible future fertility levels as birth control becomes more common and more effective.

Unwanted fertility presumably begins at a very low level in traditional societies, then increases as the small family norm develops, frequently outpacing the availability of contraception, and eventually diminishes as effective means to control fertility become widespread.

See also: Contraceptive Prevalence; Family Planning Programs; Family Size Intentions.


Bankole, Akinrinola, and Charles F. Westoff. 1988. "The Consistency and Validity of Reproductive Attitudes: Evidence from Morocco." Journal of Biosocial Science 30: 439–455.

Bongaarts, John. 1997. "Trends in Unwanted Child-bearing in the Developing World." Studies in Family Planning 28(4): 267–277.

Freedman, Ronald, Pascal K. Whelpton, and Arthur A. Campbell. 1959. Family Planning, Sterility and Population Growth. New York: McGraw-Hill.

Lightbourne, Robert E. 1985. "Individual Preferences and Fertility Behavior." In Reproductive Change in Developing Countries: Insights from the World Fertility Survey, eds. John Cleland and John Hobcraft. London: Oxford University Press.

Lightbourne, Robert E., and Alphonse MacDonald. 1982. "Family Size Preferences." In WFS Comparative Studies. Voorburg, The Netherlands: International Statistical Institute.

Osborn, Frederick. 1963. "Excess and Unwanted Fertility." Eugenics Quarterly 10(2): 59–72.

Westoff, Charles F., Robert G. Potter, Philip C. Sagi, and Elliot G. Mishler. 1961. Family Growth in Metropolitan America. Princeton, NJ: Princeton University Press.

Westoff, Charles F., and Norman B. Ryder. 1977. "Wanted and Unwanted Fertility in the United States." In The Contraceptive Revolution. Princeton, NJ: Princeton University Press.

Whelpton, Pascal K., and Clyde V. Kiser. 1950. "The Planning of Fertility." In Social and Psychological Factors Affecting Fertility. New York: Milbank Memorial Fund.

Charles F. Westoff

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