Continuation rates for oral contraceptives and hormone replacement therapy

The ESHRE Capri Workshop Group*

Correspondence: Correspondence should be addressed to Professor P.G. Crosignani, Clinica Ostetrica e Ginecologica I, Facolta de Medicina e Chirurgia, Universita Degli Studi di Milano, Via Commenda, 12-20122 Milano, Italy. E-mail: piergiorgio.crosignani{at}unimi.it


    Abstract
 Top
 Abstract
 Introduction
 Availability and uptake
 Time factors of therapeutic...
 Continuation rate of OC...
 Counselling to improve OC...
 References
 
Despite the safety and effectiveness of low oestrogen-dose oral contraceptives (OC) and postmenopausal hormone replacement there is poor continuity of use of these agents by women. Patterns of use and the reasons affecting different frequencies of use in different countries are presented. Continuity and discontinuation rates are difficult to assess accurately but it is believed that the main reasons why women discontinue use of these agents are concerns about their perceived health risks and the presence of, or fear of, adverse clinical effects, particularly unscheduled uterine bleeding and weight gain. More information is needed about OC continuation rates in order to improve the acceptability of these safe, effective agents. Most women discontinue use of postmenopausal hormonal replacement within 2 years of initiating the therapy. Reasons include disappearance of symptoms of oestrogen deficiency, lack of awareness of health benefits of oestrogen, presence of side-effects (such as breast tenderness and weight gain), presence of uterine bleeding and increasing age. Suggestions to increase continuation of OC include extensive individual pretreatment counselling with a different emphasis in different age groups, education at the time of follow-up visits and telephone calls, and extensive use of educational aids such as brochures, pamphlets and audio tapes, and improvement of pharmaceutical packaging information. In conclusion there is an urgent need to assess the value of these strategies by long-term large controlled studies.

Key words: counselling/discontinuation rates/hormone replacement therapy/oral contraception


    Introduction
 Top
 Abstract
 Introduction
 Availability and uptake
 Time factors of therapeutic...
 Continuation rate of OC...
 Counselling to improve OC...
 References
 
Hormonal contraception is the most effective reversible method of contraception and oral contraception (OC) is its most widely used form. The chief advantages of OC are simplicity and safety, and that the products are widely available and can be easily taken by mouth. The chief disadvantage is the need to take a pill every day for as long as contraception is desired.

Because OC use is simple and effective and discontinuation of OC use terminates the contraceptive effect, an important objective of research into reasons for cessation is to find and address any modifiable reasons for premature discontinuation of OC use while contraception is still required.

The climacteric is frequently characterized by perimenopausal cycle disorders, vasomotor symptoms (hot flushes and night sweats) and adverse urogenital symptoms and complaints (vaginal dryness, micturition disorders). In addition to these typical climacteric symptoms there may also be other, more atypical symptoms, such as irritability, mood swings and joint pains. The climacteric cannot be completely characterized as a phase of declining oestrogens, nor can the postmenopausal state be characterized solely as a state of oestrogen deficiency. Nevertheless, many of these symptoms and complaints of climacteric and postmenopause have been shown to disappear with the administration of exogenous oestrogens, either alone or in combination with progestogens. Hormone replacement therapy (HRT) can be defined as perimenopausal and postmenopausal medication with oestrogens or a combination of oestrogens and progestogens to treat climacteric symptoms or to prevent of postmenopausal disorders, such as osteoporosis and cardiovascular disease. HRT given to treat menopausal symptoms is highly effective and it can be continued for preventive reasons. Despite the well-documented advantages of both short-term and long-term HRT, initiation of HRT and its continuation rate are generally poor.


    Availability and uptake
 Top
 Abstract
 Introduction
 Availability and uptake
 Time factors of therapeutic...
 Continuation rate of OC...
 Counselling to improve OC...
 References
 
OC
Patterns of contraceptive use vary in different countries. OC has, until very recently, not been approved as a contraceptive method in Japan. Prior to this approach women who wanted to use OC needed to have it prescribed by a gynaecologist for management of a (real or imagined) gynaecological condition, such as menorrhagia. In some countries, particularly developing countries, OC is little used because, compared with other methods, it is expensive.

In the developed world, OC is licensed for contraception and affordable to most people, although it must be prescribed by a physician. Some of the highest levels of OC use are in Europe, but with differences between countries in patterns of use. In the UK, OC is the most popular method of contraception, with 48% of women aged 20–24 years using it (Schering Consumer Contraception Survey, 1996Go). In Denmark 33% of young single women utilize OC (Svare et al., 1997Go), while in the USA a survey undertaken in 1995 found that only 17% of women of reproductive age were using OC (USA National Survey of Family Growth, 1995Go). In the USA, the most popular method of birth control is sterilization, with 15% of women aged 25–29 years and 51% of those aged 40–44 years having been sterilized. We can only speculate on why sterilization is such a popular choice in the USA and why relatively few women continue to use hormonal contraception.

Women and men choose different methods of contraception for a variety of reasons (Table IGo) and many will use a number of methods during their reproductive lives. Some methods are more appropriate than others at certain times of life, OC for example is less likely to be used by the very young and by women approaching menopause.


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Table I. Motives for chosing a given contraceptive method currently used in Great Britain (percentages) (Oddens et al., 1994aGo)
 
Nevertheless factors in the choice of contraceptive method fall into three groups:

(i) The perceived properties of each method (e.g. reliability, ease of use, degree of interference with sex) and the perceived risks.
In order to be effective, OC must be taken reliably. Many women find it difficult to remember to take a pill every day and one of the attractions of the long-acting methods of contraception, especially intrauterine device and implants, is that once inserted nothing further needs to be done for at least 5 years.
The non-contraceptive health benefits of the pill are widely recognized (Table IIGo) and some women find the short, light and reliable withdrawal bleeds associated with OC use a reason to continue using it right up to the menopause.
(ii) Demographic factors, such as country of residence, ethnicity, age, marital status, education and fertility intentions.
Many young women start their reproductive lives using condoms. As they become more sexually active, more aware of the limitations of condoms, and perhaps more confident about approaching a clinician for contraceptive advice, many shift to the pill. In the UK the peak of OC use is in the 20–24 year old age group. In a recent study of pre-provision of emergency contraception (Glasier and Baird, 1999Go), 36% of a group of women using condoms changed to the pill over the course of 1 year. After age 24 years the use of OC tends to decline. In a longitudinal study in Sweden (Larsson et al., 1997Go) reporting 10 years of contraceptive practice among the same group of women, 51% of women were using OC at age 24 years compared with only 22% at age 29. Pill use also declines with increasing parity, as women choose long-acting or permanent methods of fertility regulation after child bearing is complete.
(iii) Outside influences, such as views and beliefs of the provider, the media (e.g. the pill scare), public beliefs (e.g. human immunodeficiency virus) and cost.
There are widespread misconceptions about OC. It is little used in China where many women believe that it makes them fat and hairy. In the UK there is a general belief that taking hormones is `bad for you' and surprising numbers of women will continue to use less reliable barrier methods, even after experiencing method failure and unwanted pregnancy because they don't want to `poison' their bodies.
In conclusion, uptake of any method depends on its availability, accessibility (including the need to see a physician), perceived efficacy and side-effects, cost, acceptability and, often, folklore and myth. Many of these factors are interrelated.


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Table II. Non-contraceptive benefits of oral contraceptives (OC) (Mishell, 1993Go)
 
HRT
Many factors are known to influence uptake and continuation rates of HRT. The proportion of peri- and postmenopausal women using HRT varies considerably. At present, it is estimated that in developed countries, 20–30% of women aged 45–60 years use HRT.

Among the factors influencing uptake, the following are recognized:

(i) Severity of menopausal symptoms. Although the majority (~75%) of peri- and postmenopausal women experience menopausal symptoms, only a minority (~22%) reported their complaints as severe (e.g. Porter et al., 1996). In a Danish survey (Oddens and Boulet, 1997Go), two-thirds of all women with symptoms consulted a physician, half of these women were then prescribed HRT (34% of total) and 49% of these actually started treatment.
(ii)Prevention reasons. A minor fraction, generally over 50 years, starts HRT because of osteoporotic concerns (Cauley et al., 1990Go; Oddens and Boulet, 1997Go).
(iii) Country of residency. There is a wide variation among various countries, even within the developed part of the world (e.g. Italy 3%, Netherlands 3.6%, UK 7%, France 12%, Denmark 12%, Germany 25%, USA 38%) (Oddens et al., 1992Go, 1994bGo; Keating et al., 1999Go). In recent years, in many countries the prevalence of uptake of HRT has increased considerably, for instance in the UK uptake increased from less than 5% in 1987 to almost 30% in 1994 (Townsend, 1998Go) (Table IIIGo).
(iv) Menopause status. Perimenopausal women (20%) use HRT more often than postmenopausal women (9%) (Oddens et al., 1992Go, 1994bGo).
(v) Surgical status. Current use is three times more common after hysterectomy (Keating et al., 1999Go) and especially bilateral oophorectomy (Cauley et al., 1990Go; Oddens and Boulet, 1997Go).
(vi) Social status. Use is more common among more highly educated women (Keating et al., 1999Go) (Table IVGo) and by female doctors (Isaacs et al., 1995Go).
(vii) Health status. HRT use is less common among women with a disease such as diabetes mellitus (Keating et al., 1999Go) or a history of breast cancer.
(viii)New technologies. Use of HRT increased with the introduction of the patch and possibly also with the medicated IUD.
(ix) Others. Uptake of HRT use is more frequent in previous OC users (Hammar et al., 1996Go) and in women who regularly exercise or do sports.


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Table III. Current use of hormone replacement therapy in various countries
 

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Table IV. Hormone replacement therapy (HRT) use and education among 495 postmenopausal women, 50–74 years of age, USA, 1999 (Keating et al., 1999Go)
 
The study of McNagny et al. (1997) concluded that current users of HRT were significantly more likely to be younger, white, sexually active, to be previous users of OC, to have had a hysterectomy, to have no personal or family history of breast cancer and to be female gynaecologists. Of women physicians, 47.7% overall were users. The percentage of users in the age group from 40 to 49 years was 59.8%. There is very little information on long-term use and use by women older than 60 years.


    Time factors of therapeutic and side-effects of OC
 Top
 Abstract
 Introduction
 Availability and uptake
 Time factors of therapeutic...
 Continuation rate of OC...
 Counselling to improve OC...
 References
 
OC
Time factors in OC use are key aspects of their therapeutic effects and also for defining and evaluating their side-effects. Some of these factors have been widely investigated in epidemiological studies, enabling us to formulate the following conclusions, with specific reference to OC:

(i) Duration of use is not a major determinant of risk of breast cancer, nor of cardiovascular disease. In fact, among 35 767 controls who had ever been OC users in the Collaborative Group of Hormonal Factors in Breast Cancer (CGHFBC, 1996aGo,bGo), 25% had used OC for <1 year, 37% for 1–4 years, 24% for 5–9 years, 11% for 10–14 years, and 3% for >=15 years. The risk of breast cancer was not related to duration of OC use, but was higher [relative risk = 1.24, 95% confidence interval (CI) = 1.15–1.33] for current than for those who had never been OC users.
(ii) With reference to age at first use, 13% had first used OC at age <20 years, 29% at age 20–24 years, 23% at age 25–29 years, 17% at age 30–34 years and 18% at age >=35 years. While a potential role of OC use at very young age (i.e. <18 years) on breast cancer risk remains open to discussion (CGHFBC, 1996bGo), use at age >=35 years, and even more at age >=40 years, should be evaluated in terms of benefits/risks, for both breast cancer and cardiovascular disease. Information is, however, limited for age at last use.
(iii) Although time since first use has no important effect on subsequent OC risks or benefits, time since last use, including current use, is a determinant of cancer and cardiovascular disease risk. The favourable effect of OC on endometrial and epithelial ovarian cancer is long-lasting (Franceschi et al., 1991Go; Whittemore et al., 1992Go), but detailed information on time-related factors is inadequate. There is also only limited information about patterns of OC use (continuous versus interval use).
(iv) Periodic discontinuation of OC use is not rational for contraceptive purposes, but has frequently been adopted in the past in several countries, without any justification (Parazzini et al., 1996Go).

HRT

(i) In the control group of the CGHFBC (1997) study, 28% of the women had used HRT for <1 year, 4% for 1–4 years, 19% for 5–9 years, 9% for 10–14 years and 6% for >=15 years. It is therefore clear that more than 30% of women had used HRT for short periods (<4 years), most likely for control of menopausal symptoms only. Such a pattern of use conveys no material benefit or risk for any disease. Duration of use is longer in North America, but generally shorter in Europe, especially in southern Europe (Hemminki et al., 1988Go; Parazzini et al., 1993Go).
(ii) Most risks and benefits of HRT are restricted to current users, or to the short term after stopping use (Tavani and La Vecchia, 1999Go). Thus, information on time since last use and age at use is important in order to define the pattern of risks and benefits, since breast cancer is more frequent than cardiovascular disease below age 60 years, whereas cardiovascular disease and osteoporotic fractures are more common in elderly women. For HRT, therefore, the issue of duration of use and age at last use are of major importance on individual and public health levels, and would appreciably modify any practical indication for prescriptions. More information on HRT use above age 60 would, in any case, be important.


    Continuation rate of OC and reasons for discontinuation
 Top
 Abstract
 Introduction
 Availability and uptake
 Time factors of therapeutic...
 Continuation rate of OC...
 Counselling to improve OC...
 References
 
Continuation and discontinuation rates are difficult to assess reliably and good data are few, since data from clinical trials are generally short-term and thus not representative. The limited data that do exist suggest that the most common reason for stopping the OC is to become pregnant. In general, in any one year 10–15% of women will stop using OC. Fear of risks and the presence of side-effects (whether real or perceived) and, especially, weight gain account for many discontinuations.

Although the absolute risks of serious side-effects are extremely small, nevertheless some women do not even start the pill because of fears concerning safety (Oddens et al., 1994aGo; Larsson et al., 1997Go). Fear of the more serious risks will also lead to cessation of pill use. In the Swedish study (Larsson et al., 1997Go) more than 30% of 29 year old women gave `fear' as the main reason for stopping the pill. The media, tending to report only negative news about contraception and to sensationalize that news, are quite effective in this respect. The `pill scare' of 1995 was said to have resulted in 25 000 women in Norway stopping the OC in November and December of 1995 (Skjeldestad, 1997Go).

The continuation rate in women taking OC in a survey of 29 studies has been compared to the compliance with other medical treatments and, surprisingly, the rates of compliance differ little from rates of compliance with other treatments (Cramer, 1996Go).

The majority of epidemiological studies in this area are cross-sectional designs which provide information on contraceptive methods in use and the proportion of the population using each method, but no data on discontinuation. A 1997 study from Sweden, however, details reasons for discontinuation, and provides longitudinal data over 10 years from subjects in the same representative sample (Larsson et al., 1997Go). The sample comprised 25% of the women aged 19 years in Göteborg in 1981, the data were collected in 1981, 1986 and 1991, and the response rate in the last survey was 74% of the original sample. From 1981 to 1991, the proportion remaining unmarried changed from 94% to 45%, the proportion using any contraceptive method changed from 61% to 75%, and the proportion using OC alone or in combination with another method changed from 48% to 26%. Reasons for discontinuing OC were similar at ages 19, 24 and 29 years. The most common reason was fear of OC side-effects (34% at age 29). Although the authors cite several reports in the mass media that were associated with reductions in national sales of OC, their survey questionnaire did not seek information on the precipitating cause of the fear in individual women. Other reasons included: contraception not required (19%), mood disorders (19%), weight gain (16%); and menstrual disorders (12%).

Of course, the single reason for discontinuation which changed dramatically with age was the desire to become pregnant, rising from 6% at age 19 to 32% at age 24 years and 52% at age 29 years.

Subjects enrolled in randomized clinical trials (RCT) are not typical OC users because they agree to additional follow-up, accept an uncertain treatment allocation and generally are committed to a fixed interval of use within the duration of the trial. RCT data are useful, nevertheless, in part because the follow-up is more intense than in clinical practice, and the data collected are more complete and detailed. Of 14 randomized controlled trials, three trials published in the 1990s annotate reasons for discontinuation of OC. Two of these trials were conducted in developing countries (McLaurin and Dunson, 1991Go; Koetsawang et al., 1995Go), and accrual for the other took place in the 1980s (Percival-Smith et al., 1990Go).

In the largest of these trials, reasons for stopping use in the 12 month study were similar for a 1 mg norethindrone monophasic with 35 or 50 µg ethinyl oestradiol (McLaurin and Dunson, 1991Go). Among the 1602 subjects, 26% discontinued for the following reasons: non-medical (13%), breakthrough bleeding (4%), other side-effects (4%), and planning pregnancy (3%).

In another trial, continuation rates at 6 months were 88% and 86%, respectively, for a 30 µg ethinyl oestradiol monophasic with 150 µg desogestrel or 75 µg gestodene (Koetsawang et al., 1995Go). Among the 783 subjects, 7% discontinued for the following reasons: non-medical (3%), breakthrough bleeding (0.3%), other side-effects (3%), and planning pregnancy (0.5%).

In a 1980s trial, the reasons for stopping use were similar for a 30 µg ethinyl oestradiol monophasic, a biphasic and two triphasic preparations (Percival-Smith et al., 1990Go). Among the 469 subjects 300 continued to the end of the six cycle trial period; breakthrough bleeding or spotting was the reason for discontinuing of 6%.

The subjects involved in non-experimental follow-up studies may be more typical of OC users, although they frequently consent to use an investigational drug product. A recent large open-label multicentre study involved 1477 women, and 7870 cycles of use of the study product (levonorgestrel 100 µg and ethinyl oestradiol 20 µg) (Archer et al., 1997Go). Over 50% (792 women) had completed more than six cycles of use at the time of the interim report. In this North American trial, 131 subjects discontinued because of adverse events, the most common of which were headache (1%) and breakthrough bleeding (1%). Other side-effects causing discontinuation in less than 1% of subjects were amenorrhoea, depression, emotional lability, hypertension, acne, menorrhagia, nausea, hypercholesterolaemia, weight gain, dysmenorrhoea and flatulence.

Conclusions
Although acceptance and continuation of OC is less than ideal, little is known of the reasons for discontinuance. Women involved in follow-up and experimental studies frequently cite more than one reason. The reason cited most often by women in a community survey (fear of OC) was not mentioned in any follow-up and experimental studies. There is still very little information about the following points:

(i)use of OC for longer than 15 years;
(ii)use of OC by women who are 35–40 years old;
(iii)continuous versus discontinuous use.

Clearly, more information is needed about the dynamics of OC continuance in order to improve the acceptability of this effective contraceptive agent.

HRT
Generally, HRT is continued for less than 2 years. Factors that influence continuation after 1–2 years are the following:

(i) Symptoms. Both effective therapy (disappearance of complaints) and ineffective therapy are reasons for discontinuation (Oddens and Boulet, 1997Go).
(ii) Preventive reasons. There is no great awareness of preventive reasons for use of HRT in climacteric women (Oddens and Boulet, 1997Go).
(iii) Side-effects. Side-effects, which can be real (bleeding, breast tenderness) or presumed (weight gain), are major factors in discontinuation.
(iv) Uterine status: continuation is much more common in hysterectomized women (Oddens and Boulet, 1997Go; Keating et al., 1999Go).
(v) Regimens chosen. Regimens that do not induce withdrawal bleeding (continuous combined HRT, Tibolone) are used much longer than regimens that induce bleeding (sequential) (Nachtigall, 1990Go; Doren and Schneider, 1996Go; Oddens and Boulet, 1997Go).
(vi) Age. For all the reasons mentioned above, or as a reason on its own, the rate of continuation decreases with age (Vestergaard et al., 1997Go).
(vii) Others. Previous OC use is not a factor. Regular exercise is associated with a better continuation rate (Oddens and Boulet, 1997Go).

A large proportion of women stop on the basis of advice from their family physician.

A French study (Berthet et al., 1995Go) found an overall adherence to HRT of 30% in postmenopausal women and concluded that a better continuation rate depends largely on better information from the physicians and the drug companies. Better health care education is needed. In the USA (Ettinger et al., 1998Go), it has been observed that the continuation rate was significantly better in women taking peroral than transdermal HRT: the relative risk for discontinuation was 2.7 (95% CI: 1.8–3.9) in the transdermal group relative to that in the oral group, 25% of the women having transdermal patches switched to orally administered agents; however, there is no confirmation of these data from other, especially European countries.


    Counselling to improve OC continuation rate
 Top
 Abstract
 Introduction
 Availability and uptake
 Time factors of therapeutic...
 Continuation rate of OC...
 Counselling to improve OC...
 References
 
OC
Women can decide to discontinue use of OC at any time without consulting their health care providers. Therefore, it is extremely important for adequate counselling to be given at the time OC use is initiated, so that women will not discontinue using them because of minor side-effects or misperceptions about health risks associated with their use. Clinicians need to be aware of these misconceptions, become knowledgeable about the evidence refuting them and counsel women about this evidence. There are very few studies in which strategies to improve OC compliance have been evaluated (Rosenberg et al., 1995aGo). A recent programme about OC developed in the USA provided information about several aspects of patient counselling (Rosenberg et al., 1995bGo). Recommended areas of counselling differed for women in different age groups. Counselling of adolescents differed from that for young adults and perimenopausal women. Older women who have completed childbearing tend, at least in Europe, to change from OC to IUD or sterilization. The combined OC are not contraindicated for older women (over 35 years) who do not have risk factors for cardiovascular disease, e.g. smoking and hypertension. Indeed, the additional benefits beyond contraception for OC are particularly relevant to older women, who have a higher incidence of menstrual problems and an increasing risk of ovarian and endometrial cancer. The report concluded that it is best if the counselling is individualized to address the concerns of each woman, based upon her baseline knowledge. Information about the perceived risks of OC use, cancer and cardiovascular disease should be clarified. Information about non-contraceptive benefits should be given (Table IIGo). Potential side-effects and their transient nature should be discussed and instruction regarding correct OC use should be given. OC users should be encouraged to call the practitioner's office about any concerns that may arise after OC use is initiated. OC providers need to include all members of the office group so that consistent messages are given to women who ask questions by telephone. To reduce the number of women discontinuing OC use, it would be helpful to establish written question-and-answer protocols so that non-medical staff can answer basic questions. Follow-up visits and telephone calls by patients should be regarded as opportunities to enhance continuation of OC use. Interactive communication should be used at these times. The potential OC user should also be encouraged to read literature about the product which has been written for the consumer. A randomized trial was performed in Britain in which either information leaflets or a blank control were given to women when they visited practitioners for repeat prescriptions of OC (Little et al., 1998Go). Half the women were also questioned about their knowledge of OC. Three months later the women completed a questionnaire. Women who had read the leaflet or were asked questions initially had significantly greater knowledge of OC than those who had not. A Dutch study analysed OC compliance among OC new users and those who switched to a new formulation (Deijen and Kornaat, 1997Go). All women were interviewed by the physician regarding OC action and side-effects. The women were then randomly given (i) no additional information, (ii) two printed brochures, (iii) the brochures plus information on audio tape. At the end of 1 and 3 cycles of pill use, assessments were made of attitude, compliance, and management of missed pills. It was determined that use of the brochures and audio tapes significantly increased knowledge of the medical advantages of the OC and decreased the number of OC missed. The investigators did not analyse continuation of use. In addition to these ways to enhance OC compliance, Rosenberg et al. (1995a) suggested that OC manufacturers develop new OC packaging to enhance compliance and develop a standardized content of instruction and reminder materials that are comprehensible to women with different degrees of education. Additional studies need to be undertaken to see whether use of these techniques improves OC continuation rates.

HRT
Obviously, if HRT continuation is considered to be desirable, as it is for OC, a good counselling programme is essential. The programme can be summarized as follows:

(i) Provision: primary care doctors and nurses, specialist doctors and nurses, friends and relatives and the media.
(ii) More time for consultation. In the UK, the primary care doctor spends an average of 7 min with each patient.
(iii) This is supplemented with nurse counselling and with printed information. It was emphasized that the counsellors should check the correctness of this information.
(iv) The patient should be well-informed about the risk/benefit ratios, both individual- and age-specific. They should also be informed about possible side-effects.
(v) The patient should have easy access to expert help.
(vi) The patients should be informed about existing alternatives (lifestyle, drugs) for `prevention' or `control' of the condition for which they are taking HRT. Probably these should be integrated with the HRT.
(vii) Pharmaceutical companies should be urged to be precise and to update packaging information and inserts.

In conclusion, the strategies which may improve compliance include better information and education.

Finally, since there are very few solid data available at present, the group emphasized the urgent need for long-term and large studies.


    Notes
 
1 A meeting was organized by ESHRE (Anacapri, August 28–30, 1999) with financial support from Schering S.p.A. to discuss the above subjects. The speakers included M.H.Birkhauser (Bern), J.Collins (Hamilton), A.Glasier (Edinburgh), U.Habenicht (Berlin), P.Kenemans (Amsterdam), C.La Vecchia (Milano), D.R.Mishell (Los Angeles), J.C.Stevenson (London) and B.Tarlatzis (Thessaloniki). The discussants included D.T.Baird (Edinburgh), P.G.Crosignani (Milano), E.Diczfalusy (Rönninge), M.Meschia (Milano), L.Puglisi (Milano) and S.O.Skouby (Copenhagen). This report was prepared by P.G.Crosignani and B.L.Rubin. Back


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 Top
 Abstract
 Introduction
 Availability and uptake
 Time factors of therapeutic...
 Continuation rate of OC...
 Counselling to improve OC...
 References
 
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