Over the last thirty years, Brazil has experienced one of the most extraordinary fertility declines in the world. The national fertility rate had remained practically constant until the 1960s when it started to rapidly decrease. However, strong regional differences could be noted. In fact, a reduction in fertility levels was already underway during the 1950s in the states of Rio de Janeiro and São Paulo, although this was generally restricted to better-off income groups, particularly in urban areas. Any negative influence on the national fertility rate was offset by higher and even increasing rates in other regions (Merrick, 1983; Wood and Carvalho, 1994). The overall decrease in the total fertility rate (TFR) was observed at 11 percent over the period 1940 to 1970 (Wood and Carvalho, 1994), a figure that was quickly overtaken by a rate of decline of 24.5% between 1970 and 1980 (Martine, 1996). The pace was even faster in the following decade: an impressive drop of 40 percent between 1980 and 1991. In short, the TFR for the whole of Brazil declined from 5.8 to 2.8 in just two decades. Moreover in the Northeast, the poorest region of the country, the TFR fell from 7.5 children per woman in 1970 to 3.7 in 1991, with almost half of this decline occurring in the last five years of the period
(Ferraz et al., 1992). Such decline is still more remarkable upon taking into account the fact that Brazil never had any widespread family planning programme sponsored by the government.
As emphasised by Martine (1996), the fertility decline in Brazil was only slightly slower than that observed in China and more rapid than that which occurred in countries such as Indonesia, India, Pakistan, Bangladesh and Mexico, which experienced aggressive family planning programmes over several decades. Use of efficient methods of contraception, basically oral contraceptives (the pill) and sterilization, has proved to be the most important determinant of the sharp fertility decline which has taken place in Brazil (Merrick and Berquó, 1983; Wood and Carvalho, 1994). The majority of studies on differential fertility in Brazil have focused on contraceptive prevalence, where regression models have been applied to evaluate factors affecting use and choice of methods of contraception (Rios Neto et al., 1992; Alencar and Andrade, 1991). This is also true for the studies specific to the Northeast region (Faria and Potter, 1990; Perpétuo, 1996). However, in order to fully understand the mechanisms through which use of contraception plays a role in fertility decline it is imperative to investigate the components of contraceptive dynamics, such as contraceptive failure and switching. High levels of prevalence of contraception alone do not necessarily result in low levels of fertility. As prevalence increases, fertility levels become increasingly dependent on effectiveness and duration of use of a Contraceptive Switching in Northeastern Brazil, 1986-91 method. The study of contraceptive dynamics emerges as even more important in areas where fertility is higher and particularly during a process of transition, as in Northeast Brazil, as it may provide insights to a better understanding of women’s behaviour regarding their reproductive strategies.
Contraceptive switching is by far the least studied of the components of contraceptive dynamics. This is particularly a result of the absence of suitable data. Historically most sample surveys on reproductive events have been limited to the collection of information on current or ever use of contraceptive methods, including the Demographic and Health Surveys (DHS).
However with the inclusion of a calendar component in the second phase of the DHS questionnaire, there has been an increasing number of studies on contraceptive switching (Kost, 1993; Curtis and Hammerslough, 1995; Steele, 1996). In this paper calendar data are used to analyse contraceptive switching in Northeast Brazil. They provide information enabling research into questions such as: Do women who discontinue a method of contraception change to another one or do they abandon use altogether? In the case of change to another method, which new contraceptive method is chosen? What are the sociodemographic characteristics of those who abandon use altogether as compared with those who change to another method? These issues are taken up in this paper.