Mon compte |
Mon panier d'achats |
Ma bibliographie 
Contacts |
Aide 
Population (english edition)
I.N.E.D

I.S.B.N.sans
200 pages

p. 347 à 356
doi: en cours

Veille sur la revue
Veille sur l'auteur
Acquérir ce numéro
Vous consultez

Volume 59 2004/3-4


Discipline > Revue > Sommaire > Article
Police normale Agrandir la police Imprimer l’article. Nouvelle fenêtre


2004 Population

Introduction

Nathalie Bajos Henri Leridon Nadine Job-Spira
Following on from the surveys on contraception conducted by INED in 1978, 1988 and 1994 (Leridon et al., 1987 ; Toulemon and Leridon, 1992 ; de Guibert-Lantoine and Leridon, 1999), a multidisciplinary team of researchers from INSERM, INED and CNRS elaborated a research programme on contraceptive practices and recourse to abortion in the 2000s. Two surveys designed to complement each other were initiated.
The first was a qualitative survey, conducted on 71 women who had recently experienced an unplanned pregnancy, with the aim of understanding the logics behind contraceptive and abortion practices in relation to social, emotional, relational and contraceptive courses (Bajos, Ferrand and the GINE group, 2002). The results from this research are not presented directly in the articles published here, but they served in developing the questionnaire for the quantitative survey and contributed to structuring and orienting the interpretation of results from the quantitative analysis.
Second, a socio-epidemiological cohort was created in the form of a representative sample of 2,863 women followed up annually over five years in what is known as the COCON (COhort CONtraception) survey [1]. The articles published here present the first results from this survey.
The objectives of this programme were to describe and analyse :
  • trends in contraceptive practices and histories, availability and acceptability of different contraceptive methods ;
  • the circumstances of contraceptive failure and measurement of the use-effectiveness of contraceptive methods ;
  • the decisional processes behind the choice of pregnancy outcome in the case of unplanned pregnancy ;
  • the patterns of access to health care for induced abortions ;
  • the health effects of contraceptive and abortive methods.
From a sociological perspective, practices in matter of contraception and abortion are conceptualized as elements of social contexts which structure the demand from women and the level of care provision. For its part, the epidemiological approach views these practices as risk factors for unplanned pregnancy or for side-effects on women’s health, and also considers the effects of abortion on subsequent pregnancy outcomes. The research team’s multi-disciplinary membership permits a comparison of these different disciplinary approaches : the sociological approaches can take into account the health effects of contraception and induced abortion, while the epidemiological analysis can include social variables that may be determinant for explaining the health effects of contraception or for measuring exposure to the risk of unwanted pregnancy.
The decision to conduct a cohort survey reflects the need to obtain accurate data on a practice that evolves rapidly at the individual level, since women change contraception relatively frequently, especially in the case of the various types of oral contraceptive. There is a danger that retrospective collection of detailed data on prior medication, observance of user instructions, problems of clinical tolerance and the reasons for choices made, will not yield wholly reliable information more than one year afterwards. Annual follow-up is a means of limiting recall bias.
Selection of the initial sample (COCON survey 2000)
The sample was selected using a two-stage methodology that has become well established for this mode of data collection since the ASCF survey on sexual behaviour in France conducted in 1992 (Riandey and Firdion, 1996). The initial COCON sample was formed by random selection in the list of fixed-line telephone subscribers of France Télécom. At the time the sample was being prepared (early-2000), 90% of French households were estimated to possess a fixed-line telephone (Beck, Legleye and Peretti-Watel, 2004). Data collection took place in autumn 2000 (between October 2000 and January 2001), using the computer-assisted telephone interviewing (CATI) system. Interviewers of both sexes, trained by the research team, performed the interviews. Shortly before data collection began, all the households whose names and addresses had been identified through the reverse directory [2] were sent an advance letter announcing the survey, with the aim of improving the response rate (Bajos, Spira et al., 1992).
The first stage involved random selection of 59,866 numbers from the telephone directory. In order to reach “liste rouge” subscribers (who have asked not to appear in the public directory), the digit 1 was then added into each of the numbers originally selected. This produces a new sampling frame covering in theory all households with a fixed-line telephone.
Of all the numbers in the sampling frame thus constructed, 39,562 resulted in a contact (Table 1). The other numbers were non-attributed or were fax numbers, or were never obtainable. In addition, many numbers belonged to households that contained no woman eligible for the survey. A total of 14,704 households were eventually identified as eligible, i.e. containing at least one woman aged 18-44, resident in France and speaking French. In households with two or more eligible women, the last birthday method was used to select one of them. 3,162 households or eligible women refused the interview from the outset, and a further 421 were excluded from the frame of eligible individuals (women selected but non-contactable, very early abandons). In all, 11,121 women were randomly selected as described below, in the second stage of the sampling procedure that was designed to over-represent certain categories of women.

Table 1
Selection of the COCON 2000 sample
IMGIMGTelephone numbers Number Initial sam...IMGIMF
Telephone numbers Number Initial sampling frame 59,866 Occupied, fax number, non-attributed, no answer 20,304 Contacted frame 39,562 Out of scope (holiday or weekend home, business, non-French-speaking household) 2,970 Not eligible 21,888 Eligible frame 14,704 Woman not contacted 270 Refusal at start of survey (household or woman) 3,162 Refusal after screener questions 151 Selection frame 11,121 Survey sampling frame: 11,121 women of which Automatic inclusion Selection by random sampling Selection frame 1,079 10,042 Women selected 1,079 1,930 Refusals 45 101 Completed questionnaires 2,863

Screener questions at the start of the interview were used to divide the women into two strata. The first stratum included the women who reported that their last pregnancy was unplanned or who had undergone an induced abortion in the previous five years. Since one of the principal objectives of the COCON survey was to study contraceptive failure, these women were over-represented by being systematically included in the sample (n= 1,034). The other women were assigned to the second stratum, from which 19% (n= 1,829) were selected at random. In all, the final sample of the COCON 2000 survey included 2,863 women.
Given the specific features of the sample design, weightings must be used when analysing the data. A first weighting was calculated equal to the inverse of the selection probability, and is thus a simple extrapolation coefficient. The final weighting was obtained after sample post-stratification to make the structure of the sample more like that of the female population aged 18-44 living in metropolitan France in 2000. The post-stratification variables are age, marital status, activity status and educational qualification. The maximum ratio obtained between extreme weights is 38.7 : the weight is highest when the woman is both in the second stratum (weight 5) and in a household containing a large number of eligible women.
All the results in the articles published here present weighted percentages and the crude numbers of women interviewed ; the sample design is systematically taken into account in the statistical tests.
The questionnaire answered by the women in 2000 lasted on average 40 minutes. It was elaborated using the first results from the qualitative survey, with the aim of limiting as much as possible the normative content of the questions, notably those dealing with the “contraceptive injunction” (Bajos, Ferrand and the GINE group, 2002) and the recourse to abortion. It collected information on socio-demographic characteristics, circumstances of first sexual intercourse, contraceptive and reproductive histories, last sexual intercourse, health effects of contraceptive methods, and medical and gynaecological histories, as well as on opinions and knowledge relative to contraception. A specific module collected detailed data on the last pregnancy and access to the health care system for the last induced abortion.
The follow-up surveys (COCON 2001 to 2004)
The second, third and fourth waves of the COCON survey, also referred to as “follow-up” surveys, took place in the autumn of 2001, 2002, and 2003, respectively, and the fifth and final is planned for autumn 2004. The objective on each occasion is to re-interview all the women present in the previous wave. The questions focus this time on the changes that have occurred since the last interview, notably regarding relational and professional contexts, reproductive history, the contraceptive methods used and the reasons for any changes. The average length of interview was around 20 minutes, which is less than half the time in the first wave.
A mechanism was put in place to achieve efficient follow-up of the women. For this follow-up the woman’s prior consent was required : at the end of each interview, the interviewer asked if she agreed to be interviewed the following year. In the data collection phase, if the woman could not be contacted on the telephone number given the previous year, the team called the number of a close friend or relative if this had been supplied in the previous wave (up to seven numbers were potentially usable to reach the women in 2002). If this was unsuccessful, further attempts were made to trace the woman through the telephone directory.
Considerable effort went into updating the file of women’s addresses between successive survey waves, notably to avoid losing those who changed address or telephone number in the interval. Hence, each summer before the new round of interviewing, a “COCON newsletter” presenting selected results from the survey was sent to all the women who wished to receive it. This newsletter contained a reply postcard so that women whose address or telephone number had changed could send the new one to INSERM. An advance letter was also sent to the women a few weeks before they were telephoned for re-interview. In addition, a “numéro vert” (free-phone number) was provided for them to use.
The results presented in this issue
This cohort survey, the first on the subject to be conducted in France, and by telephone moreover, required an extensive methodological effort. In addition to the stages of testing the questionnaire and optimizing the sampling frame parameters, the feasibility of a follow-up procedure for the women had to be verified, as regards both theoretical acceptance at the end of the first interview and actual acceptance when the interviewer called back 12 months later. The results of the pilot survey conducted in 1998 showed very high theoretical acceptance (7% refusals) but difficulty in contacting all of the women 16 months later (20% of women “lost to follow-up” and 13% not contacted). However, while such results indicated that the principle of a cohort could be accepted, the numbers were too small for a detailed analysis of the cohort attrition process.
Using the results from data collections carried out in 2000, 2001 and 2002, Nicolas Razafindratsima and Ngoy Kishimba give the first detailed study of attrition in a cohort interviewed by telephone, its causes, the biases it introduces and its potential effects on explanatory analysis. The authors show that loss of subjects was observed mainly between 2000 and 2001 and that it was greater for women presenting certain characteristics (the youngest, least qualified, living alone, etc.), but that it was not a source of major bias when modelling the key variables of the survey (previous induced abortion and contraceptive practice).
The underreporting of induced abortion is a common problem in population-based surveys and it received particular attention in the COCON survey. In spite of a substantial effort over issues of wording during elaboration of the questionnaire, the pilot survey revealed a high rate of underreporting, in the region of 50% (Houzard et al., 2000). A second pilot survey, seeking to limit still further the normative content of the questions and to diversify their wording on the basis of the discourses collected in the qualitative survey, achieved a slight reduction in this underreporting (Goulard and Bajos, 2000). The analysis presented here by Caroline Moreau et al. explores in detail the reasons for this underreporting and shows that it is probably not specific to the particular medical event of induced abortion. The terms used in the questionnaire and the context in which the questions are asked have an influence on how women report their experience of induced abortion.
The first analyses of data from the COCON survey show that the process of medicalization of contraception which began when contraceptive practice was legalized has continued to expand in recent years (Table 2 and Leridon et al., 2002), making French women the world’s main users of medical methods of contraception (pill and IUD). The figures for the youngest women are especially striking : at ages 20-24, more than two in three women were on the pill at the time of the survey (Table 3 and Bajos et al., 2003b). These data raise questions about the impact of this medicalization on women’s contraceptive histories and about the inequalities of access to contraception that may result.

Table 2
Main contraceptive method used in 1978, 1988, 1994 and 2000
IMGIMGFor 100 women aged 20-44: Survey yea...IMGIMF
For 100 women aged 20-44: Survey year (years of birth) 1978 (1933-1957) 1988 (1943-1967) 1994 (1949-1973) 2000 (1956-1980) Currently using contraception: 67.6 67.8 67.7 74.6 Of which: Pill 28.3 33.8 40.2 45.4 IUD 8.6 18.9 15.8 17.3 Periodic abstinence 5.5 5.0 3.9 1.3 Condom 5.1 3.4 4.6 7.4 Withdrawal 18.0 4.8 2.4 2.3 Other method(a) 2.1 1.8 0.8 0.9 Sterilization (for contraceptive reasons) 4.1 4.2 3.0 4.7 – woman 4.1 3.9 3.0 4.7* – partner (male) 0.0 0.3 0.0 0.0 Not using contraception: 28.5 28.2 29.4 20.7 Of which: Sterilized (for medical reasons only) 3.2 1.8 1.5 0.0* Sterile 1.4 2.8 2.6 1.3 Pregnant 4.8 5.4 5.1 4.0 No sexual relations 9.1 9.9 11.3 8.2 Wanting a child(b) 6.3 6.6 6.4 5.4 Not wanting a child 3.7 1.7 2.6 1.8 Total 100.0 100.0 100.0 100.0 Total female population aged 20-44 (thousands) 8,899 10,177 10,662 10,364 (a) Female barrier methods or unspecified methods. (b) Now or later; including “Don’t know” answers. * In 2000, among the sterilized women we cannot distinguish those sterilized for contraceptive reasons from those for medical reasons. Sources: INED, World Fertility Survey, 1978; Birth Control Survey (ERN), 1988; Family Situation and Employment Survey, 1994; INSERM-INED, COCON Cohort 2000.


Table 3
Main contraceptive method used in 2000 (per 100 women of each age)
IMGIMGAge on 1 January 2001 (years of birt...IMGIMF
Age on 1 January 2001 (years of birth) 18-19 (1981-1982) 20-24 (1976-1980) 25-29 (1971-1975) 30-34 (1966-1970) 35-39 (1961-1965) 40-44 (1956-1960) 18-44 (1956-1982) 20-44 (1956-1980) Using contraception Pill 53.9 68.3 56.7 43.8 33.2 28.0 45.8 45.4 IUD 0.0 0.9 7.5 18.3 27.6 29.6 16.1 17.3 Condom 9.2 8.6 7.7 8.0 6.2 6.7 7.5 7.4 Female barrier method 0.2 0.0 0.1 0.4 0.5 0.9 0.4 0.4 Periodic abstinence 0.0 0.8 0.8 0.4 2.9 1.7 1.3 1.3 Withdrawal 0.0 0.2 3.2 1.4 3.5 2.6 2.1 2.3 Other method, non-response 0.0 0.4 0.1 0.2 0.7 1.1 0.5 0.5 Sterilization (all reasons) 0.0 0.0 0.3 0.9 5.7 16.3 4.5 4.7 Not using contraception Sterile 0.0 0.0 0.6 0.5 1.7 4.2 1.4 1.3 Pregnant 1.5 1.8 7.1 6.9 3.3 0.4 3.8 4.0 No sexual relations 33.3 17.1 6.6 8.4 6.5 3.4 10.0 8.2 Trying for a child 0.0 1.4 7.0 6.9 4.5 1.9 4.1 4.4 Wanting a child 1.5 0.2 1.6 1.7 1.6 0.0 1.1 1.0 Other situation 0.4 0.2 0.7 2.3 2.1 3.1 1.6 1.8 Total 100.0 100.0 100.0 100.0 100.0 100.0 100.0 100.0 Total of reversible methods 63.3 79.2 76.1 72.5 74.6 70.6 73.7 74.6 In the case of multiple answers, the following hierarchy was adopted: sterilization, followed by the reversible methods in their order of appearance in the table. Source: INSERM-INED, COCON Cohort 2000.

In their article on contraceptive histories, Clémentine Rossier and Henri Leridon show that the retrospective data collected in the 2000 survey on women’s detailed contraceptive histories are reliable and can be used to explain the modifications that have occurred across the generations, especially among young people particularly concerned by the AIDS epidemic in the 1980s and by the need to use condoms.
The article by Nathalie Bajos et al. on social inequalities in access to contraception and to oral contraception in particular, shows how these inequalities have changed over time. Given the predominant place the pill has come to occupy, the issue now is less one of differences in use by broad categories of method (pill, IUD, other) than of new inequalities associated with the type of pill used, in terms of access and user satisfaction. A highly specific and important question concerns whether or not the product used is reimbursed by the social security system.
Other analyses
The data from the COCON survey also help to elucidate what we have termed the “French contraceptive paradox”, namely the relative stability of induced abortion rates in a context of generalized access to medical contraceptive methods of higher use-effectiveness than so-called natural methods. Thus it has been shown that contraceptive failure remains common : 30% of pregnancies today are still unplanned, and of these roughly one in two lead to a termination (Bajos et al., 2003b). Nearly two in three unplanned pregnancies occur among women who report using contraception when they became pregnant. These data reflect the difficulties women experience in the day-to-day management of their contraceptive practice. Some light was cast on these difficulties by the qualitative survey, which showed that contraceptive practice, as regards both the choice of method and its day-to-day use, is situated at the intersection of several normative logics. These logics are those of “contraceptive normality”, gender relations, and medical power, and are at times in contradiction with each other. Contraceptive failure exposes the obstacles that women can encounter when resolving these contradictions (Bajos, Ferrand and the GINE group, 2002).
In such a context, the use of emergency contraception could offer an effective “remedial” solution. Yet it appears that its use remains limited today (Bajos et al., 2003a ; Goulard et al., 2003).
When contraceptive failure occurs, one in two women terminate the pregnancy. The data show that the decisional logics differ widely depending on the phases of the life cycle (Sihvo et al., 2003), though it seems that the stability of the parental couple is almost always a fundamental factor (Donati et al., 2002).
Prior to the COCON survey no data were available on conditions of access to abortion services from the viewpoint of those most directly concerned. The COCON survey has made it possible to analyse the patterns of access followed by women (Moreau et al., 2004) and, through a combined analysis of quantitative and qualitative information, has identified a number of dysfunctionings and highlighted the social stigma still attached to induced abortion in France (Bajos et al., 2004).
The successive follow-up surveys (up to 2004) will allow us to address further issues. Prominent among these are studying the impact on women’s contraceptive histories of emergency contraception and induced abortion, improving measurement of the effectiveness of contraceptive methods, identifying obstacles to the use of emergency contraception, and analysing more fully the process of recourse to abortion. Thanks to the follow-up of the women, there will also be scope for detailed analysis of the health effects of contraception and their consequences for changes of methods over time, changes that are often accompanied by periods of contraceptive non-use during which women are particularly exposed to the risk of unplanned pregnancy.
 
BIBLIOGRAPHIE
 
Publications from the COCON survey
·  Bajos N., Goulard H., Job-Spira N. and the COCON group, 2003a, “Emergency contraception : from accessibility to counselling”, Contraception, 67, pp. 39-40.
·  Bajos N., Leridon H., Goulard H., Oustry P., Job-Spira N., and the COCON Group, 2003b, “Contraception : from accessibility to efficiency”, Human Reproduction, 18(5), pp. 994-998.
·  Bajos N., Moreau C., Ferrand M., Bouyer J., 2003, “Filières d’accès à l’interruption volontaire de grossesse en France : approches qualitative et quantitative”, Revue d’épidémiologie et de santé publique, 51, pp. 631-647.
·  Goulard H., Bajos N., Job-Spira N. and the COCON Group, 2003, “Caractéristiques des utilisatrices de pilule du lendemain en France”, Gynécologie obstétrique et fertilité, 31(9), pp. 724-729.
·  Goulard H., Bajos N. and the COCON Group, 2000, “Impact de la formulation et de la structure du questionnaire sur la déclaration des interruptions volontaires de grossesses dans les enquêtes en population générale”, 24e Congrès de l’Adelf, October 2000.
·  Houzard S., Bajos N., Warszawski J., de Guibert-Lantoine C., Kaminski M., Leridon H., Lelong N., Ducot B., Hassoun D., Ferrand M., 2000, “Analysis of the underestimation of induced abortions in a survey of the general population in France”, European Journal of Contraception and Reproductive Health Care, Vol. 5, pp. 52-60.
·  Leridon H., Oustry P., Bajos N. and the COCON group, 2002, “The growing medicalization of contraception in France”, Population & Societies, n° 318 (available on line at : hhttp:// www.ined.fr/englishversion).
·  Moreau C., Bajos N., Bouyer J. and the COCON group, 2004 (in press), “Access to health care for an abortion in France”, European Journal of Public Health.
·  Sihvo S., Bajos N., Ducot B., Kaminski M. and the COCON group, 2003, “Women’s life cycle and abortion decision in unintended pregnancies”, Journal of Epidemiology and Community Health Care, 57(8), pp. 601-605.

Other references

·  Bajos N., Ferrand M. and the GINE group, 2002, De la contraception à l’avortement. Sociologie des grossesses non prévues, Éditions INSERM (Coll. Santé publique).
·  Bajos N., Spira A. and the ACSF group, 1992, “What kind of advance letter increases the acceptance rate in a telephone survey on sexual behavior ?”, Bulletin de méthodologie sociologique, 35, pp. 46-54.
·  Beck F., Legleye S., Peretti-Watel P., 2004 (forthcoming), “Le recours au téléphone dans les enquêtes en population générale dans le domaine des drogue”, Actes des Journées de méthodologie statistique de l’Insee 2004.
·  Donati P., Cèbe D., Bajos N., 2002, “Interrompre ou poursuivre la grossesse ?” in Bajos N., Ferrand M. and the GINE group, De la contraception à l’avortement. Sociologie des grossesses non prévues, Éditions INSERM (Coll. Santé publique).
·  Guibert-Lantoine C. (de), Leridon H., 1999, “Contraception in France : An assessment after 30 years of liberalization”, Population : An English Selection, 11, pp. 89-114.
·  Leridon H., Charbit Y., Collomb P., Sardon J.-P., Toulemon L., 1987, La seconde révolution contraceptive : la régulation des naissances en France de 1950 à 1985, INED/PUF, (Coll. Travaux et documents, Cahier n° 117).
·  Riandey B., Firdion J.-M., 1996, “Private life and the telephone survey : the example of the ACSF survey”, in M. Bozon, H. Leridon (eds.), Sexuality and the Social Sciences, Dartmouth, Aldershot, pp. 83-106.
·  Toulemon L., Leridon H., 1992, “Maîtrise de la fécondité et appartenance sociale : contraception, grossesses accidentelles et avortements”, Population, 47(1), pp. 1-46.
 
NOTES
 
[1]The COCON group members are Nathalie Bajos, Nadine Job-Spira (group leaders), Hélène Goulard (coordinator), Jean Bouyer, Béatrice Ducot, Michèle Ferrand, Danielle Hassoun, Monique Kaminski, Nathalie Lelong, Henri Leridon, Caroline Moreau, Pascale Oustry, Nicolas Razafindratsima, Clémentine Rossier and Josiane Warszawski. Translated by Godfrey I. Rogers.
[2]The reverse telephone directory allows the name and address of subscribers to be obtained from their telephone number. This is impossible for “liste rouge” (ex-directory) subscribers, whose names and addresses are not in the directory, or for non-attributed numbers.
© Cairn 2007 Vie privée | Conditions d’utilisation | Conditions générales de vente
À propos | Éditeurs | Bibliothèques | Aide à la navigation | Plan du site | Raccourcis
[1]
The COCON group members are Nathalie Bajos, Nadine Job-Spir...
[suite] Suite de la note...
[2]
The reverse telephone directory allows the name and address...
[suite] Suite de la note...