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Spanish population at risk of unwanted pregnancy: Results of a national survey
Lete I*, Bermejo R**, Coll C*, Dueñas JL*, Doval JL*, Martinez-Salmeán J*,
Parrilla JJ*, Serrano I*.
*Daphne team
**Medical Division. Schering Spain.
This study was supported by a grant of Schering España S.A.
In spite of the high percentage of use of contraception, one million Spanish women are
at risk of an unwanted pregnancy
Key words: contraceptives, unwanted pregnancy
Authors’ address:
Dr Iñaki Lete
Department of Obstetrics and Gynecology
Hospital Santiago Apóstol
01004 Vitoria. Spain
Phone: + 34 945007600
e-mail: ilete@hsan.osakidetza.net
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ABSTRACT
Objective: We performed a personal survey to 2218 Spanish women aged from 15 to
49 years to establish the contraceptive methods used by this population and to determine
the number of Spanish women of childbearing age exposed to unwanted pregnancy.
Methods: A stratified random sampling was performed to select the women to be
interviewed and this sampling design ensured adequate representation of the sample in
Spain.
Results: At the time of the survey, 69.1% of the women were using some contraceptive
method, but 5% of them used poorly effective contraceptive methods, and their exposure to
the risk of an unwanted pregnancy was therefore high. Moreover, among the 30.9% not
using any contraceptive method, 21.1% were at risk because they were having sexual
intercourse, did not want to become pregnant, and did not use a contraceptive method.
Conclusions: A little over one million Spanish women are exposed to the risk of having an
unwanted pregnancy. Compiling the data on this significant problem is the first step in
designing appropriate solutions.
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INTRODUCTION
Almost all women are exposed to an unwanted pregnancy during their reproductive lives,
either for not using any contraceptive method or for failure of some of them1 . The primary
and essential objective of the use of any contraceptive method is to prevent an unwanted
pregnancy with the following consequences: elective abortion, inadequate prenatal
monitoring, negative personal, family and social impact, adoption2. The existing
differences between different countries in unwanted pregnancy rates are mainly explained
by the rates of use of contraceptive methods3. The use of contraceptive methods is
conditioned by different factors including age, socioeconomic level, health coverage,
attitude of the partner, and race4.
One of the measures proposed to improve the situation (reduce the rate of unwanted
pregnancies) is to determine local data in order to be able to promote active prevention
policies5. We, therefore, considered it appropriate to analyze the data from a national
survey on the use of contraceptive methods from the perspective of the population at risk of
unwanted pregnancy.
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MATERIAL AND METHODS
In Spain we carry out a national survey regarding the use of different contraceptive
methods. We do this since 1997 and repeat it every two years.
During the months of April and May 2001, 2218 Spanish women aged 15 to 49 years were
interviewed personally to establish their contraceptive habits.
Statistical design
A probabilistic, stratified random sampling was performed to select the women to be
interviewed. A two-staged conglomerate sampling was made, with subsampling and
stratification of the first stage units, that were the censual sections in which the country is
divided. Once the censual sections used for sampling had been selected, all homes existing
in these sections were counted, and the list of homes selected for the sample (8 per censual
section) was drawn by simple random sampling, without replacement, from the total list of
homes. When there were several women susceptible to be surveyed (15-49 years) in the
home selected, one of them was selected at random using a random number table.
This sampling design ensures the adequate geographical and social-demographic
representativeness of the sample in the whole Spain, working in over 200 townships and all
Spanish provinces.
The variables used to stratify the sample to be selected were: age, marital status,
geographical location, educational level and occupation.
Methods for collecting information
Collection of information was controlled at all times in order to prevent potential errors
occurring during field work, for which the following measures were taken: (i) use of a team
of highly-qualified interviewers (all women), (ii) design of an easy-to-use questionnaire,
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(iii) preparation of an instruction manual for interviewers, (iv) performance of a pretest
(pilot survey) of 60 surveys by 10 interviewers to analyze the potential deficiencies of the
questionnaire, and (v) random inspection of 14% of the questionnaires received.
The basic limitation of this type of sampling is that all relevant strata or segments are
adequately represented in the investigated sample. In our case, after following the above
procedure, the sample of 2218 women is representative at a national level, and such
representativeness refers to the results of the research in the specific study period.
A detailed description of the working method has been previously published6 when we
reported the data of the 1999 national survey.
For the present study, in addition to considering the use of any contraceptive method, we
intended to analyze exposure to an unwanted pregnancy. For this, we classified the
contraceptive methods according to efficacy, as shown in Table 1, considering as poorly
effective those methods with a high failure rate7 and considering too that we have not the
data of correct use of reliable methods wich fails when it can be used incorrectly.
On the other hand, as regards women not using any contraceptive method, we wanted to
know the reasons for not using them, and classified these reasons based on whether the
women did or did not have a risk of unwanted pregnancy, considering at risk of unwanted
pregnancy those women that not use contraceptive methods due to religious reasons, fear to
side effects or lack of information and at not risk those that not have sexual intercourses,
are infertile or trying to get pregnant.
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RESULTS
In Spain, there are currently 10,168,337 women aged 15 to 49 years, distributed according
to age groups as: 13% in the group of 15-19 years, 15.6% in the 20-24, 15.9% in the 25-29,
15.5% in the 30-34, 14.7% in the 35-39, 13.3% in the 40-44 and 12% in the 45-49 years
group. Of all Spanish women of childbearing age, 69.1% were using some contraceptive
method at the time of the interview, while 30.9% did not. Table 2 shows the percentage of
use of each contraceptive method comparing the data of the 1999 survey and the 2001
survey. The condom is the method most commonly used with a 29.5% of the Spanish
population using it. When analyzing the data considering their efficacy Table 3 shows the
total number of women at risk of unwanted pregnancy, 9.97% of the total female
population of childbearing age. Table 4 shows the percentages of the female population at
risk of unwanted pregnancy by age. It can be seen that the number of women exposed to an
unwanted pregnancy increases with age.
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DISCUSSION
It should first be stressed that 69.1% of Spanish women of childbearing age use some type
of contraceptive method. In a similar survey conducted in 19996, the percentage of women
using some type of contraceptive method was 60.6%, which means that in the past two
years there has been an 8% increase in the use of contraception. There are different reasons
for this increase, but we think that the role of the mass media, the main source of
information on contraception for Spanish women8, has been essential.
In spite of the high percentage of use of contraception, similar to or higher than the
percentages of use in countries such as France9 or the United States10, one million Spanish
women are at risk of an unwanted pregnancy. Of these women, 66% are at risk of unwanted
pregnancy because they do not use any contraceptive method, and the remaining 34%
because they use poorly effective contraceptive methods, unlike in other countries, such as
China, where the most common cause of unwanted pregnancy is the failure of a
contraceptive method11.
One of the main reasons reported by women for not using contraceptive methods is the fear
for their potential side effects12. A similar situation occurs in Spain, where 7.1% of women
of a childbearing age are exposed to an unwanted pregnancy for fear of the side effects of
contraceptive methods. Another factor determining the use of contraception is the health
coverage status of each social group or woman. This is not a relevant factor in Spain, since
the entire Spanish population is covered by the National Health System and, from this
viewpoint, there are no differences in the accessibility to contraception.
Local and partial data of a specific area of Spain place the percentage of unwanted
pregnancy at 29.4%13 , while the Ministry of Health data for the year 2000 state that there
were 67,000 voluntary terminations of pregnancy. In principle, it seems that the use of
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abortion is low among Spanish women, since a higher number could be expected
considering the million women exposed, but it is likely that many unwanted pregnancies
are accepted by the women and lead to term. This occurs in other countries, such as the
United States, where in spite of the decrease in the number of unwanted pregnancies, up to
49% of full-term pregnancies are not wanted, but accepted14, Canada with 45% unintended
pregnancies15, or Nigeria, where 42% of unwanted pregnancies are accepted by women16.
One of the main causes of unwanted pregnancy is the inadequate use of condoms17, which
are the most commonly used method by women in some social groups when they become
pregnant unplanned18.
Adolescents are usually considered an age group at risk for unwanted pregnancy19, which
in some countries, particularly the United States, reaches worrying rates20. In Spain, when
the concepts of use of an effective method are applied, only 2.8% of Spanish adolescents
would be at risk of an unwanted pregnancy. Despite this and the fact that adolescents using
some contraceptive method use methods with a high theoretical efficacy, mainly condoms,
the rate of voluntary termination of pregnancy in this group is 7.5 per 1000 women, higher
than in the other age groups. This paradoxical fact could be explained by inadequate use of
this effective contraceptive method and leads us to consider this a high risk group and to
continue working towards improving their contraceptive habits. Women older than 40 years
are most exposed to an unwanted pregnancy (16.6%), despite the fact that sterilization is
widely used by Spanish women older than 40 years; 38% of women trust in surgical
methods (including vasectomy). This sterilization rate is higher than in countries with a
high tradition of this type of method, such as Brazil, where the sterilized female population
reaches 25%21. We think that this is a too drastic method, considering the availability of
other reversible, highly effective methods (pill, levonorgestrel-releasing IUD).
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These women also have less abortions because their natural fertility declines
We agree that adequate knowledge of unwanted pregnancy rates represents the first step to
achieve adequate levels of reproductive health22, and consider that a strategy to decrease
the number of unwanted pregnancies should be based on a higher rate of use of effective
contraceptive methods, banning poorly effective methods, together with a policy for
addressing the reasons claimed by many women for not using contraceptive methods.
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Table 1. Classification of contraceptive methods according to their efficacy7
Highly effective methods Poorly effective methods
Diaphragm Natural or rhythm methods
Vasectomy Coitus interruptus
Intrauterine device Spermicides
Condom Others
Pill
Tubal ligation
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Table 2. Percentage of use of contraceptive methods in two different years
Methods 1999 2001
Rhythm method or natural 0.7 0.6
Coitus interruptus 4.3 2.6
Spermicide Ovule 0.2 0.1
Diaphragm 0.2 0.4
IUD 5.9 4.7
Condoms 21.9 29.5
Contraceptive pill 16.5 19.2
Tubal ligation 4.5 5.3
Vasectomy 6.4 6.5
Others 0.0 0.2
None 39.3 30.9
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Table 3. Spanish female population at risk of pregnancy
Use of contraceptive method N Percentage
YES 7,026,295 69.1
Highly effective 6,674,980 95.0
Poorly effective 351,315 5.0
NO 3,142,042 30.9
No risk 2,479,071 78.9
Risk 662,971 21.1
Population at risk 1,014,286 9.97
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Table 4. Spanish female population at risk of pregnancy by age
Contraception 15-19 20-24 25-29 30-34 35-39 40-44 45-49 years
YES (%) 43.8 74.6 73.7 72.5 76.9 74.7 63.3
Highly effective 100.0 96.8 98.6 95.2 95.2 91.2 87.7
Poorly effective 0.0 3.2 1.4 4.8 4.8 9.8 12.3
NO (%) 56.2 25.4 26.3 27.5 23.1 25.3 36.7
No risk 94.6 84.5 77.7 72.4 69.0 63.3 79.6
Risk 5.1 15.5 22.3 27.6 31.0 36.7 20.4
Population at
risk (%) 2.8 6.3 6.9 11.0 10.8 16.6 15.2