How effective are contraceptives? The determination and measurement of pregnancy rates

Cross design analysis of randomized and observational data - application to continuation rates for a contraceptive intra uterine device containing Levonorgestrel in adolescents and adults

Background

To combine results from a randomized controlled study (RCT) and an observational study (OS) to evaluate discontinuation rate of a levonorgestrel-containing intrauterine contraceptive device (LNG IUD) in a real-life setting.

Methods

We included 253 parous and nulliparous women aged 21–40 years from our own phase II RCT. A total of 1607 women of all ages (including adolescents, < 20 years) were recruited from an OS. We applied the cross design synthesis (CDS) method recommended by the United States General Accounting Office. This method combines the different strengths of RCTs and OSs into one single estimate.

Results

Combined continuation rates for parous vs nulliparous women could be estimated more precisely as well as overall continuation rates after one (86.6%) and two years (78.5%), irrespective of age and parity.

Conclusion

Cross design synthesis allowed more precise estimation of continuation rates of an intrauterine device.

Overlapping but distinct effects of genistein and ethinyl estradiol (EE(2)) in female Sprague-Dawley rats in multigenerational reproductive and chronic toxicity studies

Genistein and ethinyl estradiol (EE(2)) were examined in multigenerational reproductive and chronic toxicity studies that had different treatment intervals among generations. Sprague-Dawley rats received genistein (0, 5, 100, or 500 ppm) or EE(2) (0, 2, 10, or 50 ppb) in a low phytoestrogen diet. Nonneoplastic effects in females are summarized here. Genistein at 500 ppm and EE(2) at 50 ppb produced similar effects in continuously exposed rats, including decreased body weights, accelerated vaginal opening, and altered estrous cycles in young animals. At the high dose, anogenital distance was subtly affected by both compounds, and a reduction in litter size was evident in genistein-treated animals. Genistein at 500 ppm induced an early onset of aberrant cycles relative to controls in the chronic studies. EE(2) significantly increased the incidence of uterine lesions (atypical focal hyperplasia and squamous metaplasia). These compound-specific effects appeared to be enhanced in the offspring of prior exposed generations.

Contraceptive method at first sexual intercourse and subsequent pregnancy risk: findings from a secondary analysis of 16-year-old girls from the RIPPLE and SHARE studies

PURPOSE

Existing failure rate studies indicate that typical use of oral contraception (OC) results in fewer unplanned pregnancies than condom use, even among teenagers. However, comparative data on pregnancy risk associated with different contraceptive methods are lacking for younger teenagers starting their first sexual relationship. This study examined associations between contraceptive method at first intercourse and subsequent pregnancy in 16-year-old girls.

METHODS

Six thousand three hundred forty-eight female pupils from 51 secondary schools completed a questionnaire at mean age 16 years; 2,501 girls reported sexual intercourse. Logistic regression (N = 1952) was used to model the association of contraceptive method at first intercourse with pregnancy.

RESULTS

At first intercourse (median age 15 years) 54% reported using condoms only, 11% dual OC and condoms, 4% OC only, 4% emergency contraception, and 21% no effective method. Method used was associated with a similar method at a most recent intercourse. One in 10 girls reported a pregnancy. When compared to use of condoms only, greater pregnancy risk was found with no effective method (odds ratio [OR] 2.97, 95% confidence interval [CI] 2.12-4.15) or OC only (OR 2.44, 95% CI 1.29-4.60). Pregnancy risk for dual use and emergency contraception did not differ from that for condoms only. Both significant effects were partially attenuated by adjusting for user characteristics and sexual activity.

CONCLUSIONS

Young teenagers may use OC less efficiently than condoms for pregnancy prevention. The characteristics of those using OC-only confirm vulnerability to unintended pregnancy, and suggest that alternative contraceptive strategies should be considered for these young women.

The effectiveness of a fertility awareness based method to avoid pregnancy in relation to a couple's sexual behaviour during the fertile time: a prospective longitudinal study

BACKGROUND

The efficacy of fertility awareness based (FAB) methods of family planning is critically reviewed. The objective was to investigate the efficacy and the acceptability of the symptothermal method (STM), an FAB method that uses two indicators of fertility, temperature and cervical secretions observation. This paper will recommend a more suitable approach to measure the efficacy.

METHODS

Since 1985, an ongoing prospective observational longitudinal cohort study has been conducted in Germany. Women are asked to submit their menstrual cycle charts that record daily basal body temperature, cervical secretion observations and sexual behaviour. A cohort of 900 women contributed 17,638 cycles that met the inclusion criteria for the effectiveness study. The overall rates of unintended pregnancies and dropout rates have been estimated with survival curves according to the Kaplan-Meier method. In order to estimate the true method effectiveness, the pregnancy rates have been calculated in relation to sexual behaviour using the 'perfect/imperfect-use' model of Trussell and Grummer-Strawn.

RESULTS

After 13 cycles, 1.8 per 100 women of the cohort experienced an unintended pregnancy; 9.2 per 100 women dropped out because of dissatisfaction with the method; the pregnancy rate was 0.6 per 100 women and per 13 cycles when there was no unprotected intercourse in the fertile time.

CONCLUSIONS

The STM is a highly effective family planning method, provided the appropriate guidelines are consistently adhered to.

Grossesses survenant sous contraception orale : les leçons de l'étude GRECO

OBJECTIVES

The GRECO study has collected data on pregnancies, regardless of their outcome, that occurred in women taking an oral contraceptive.

PATIENTS AND METHODS

The analysis concerned 551 women prospectively recruited in services of gynaecology or obstetrics, termination of pregnancy centres, family planning centres or consultations of gynaecology in France throughout 2002 and who were 12 weeks pregnant or less.

RESULTS

Contraception used during the cycle of conception was an estroprogestative combination in 88% of cases, a microprogestative in 8.7%, a macroprogestative in 0.9% or another type of pill in 2.4%. Progestatives were levonorgestrel 59.0%, gestoden 17.2%, desogestrel 4.7%, norethisterone acetate 2.9%, norgestimate 1.8%, cyproterone acetate 2.0%, norgestrel 1.6%. When asked about the potential cause of the oral contraceptive failure, 76.9% of women reported events such as missed pills which were the most frequent cause of failure (60.8% of failures and 80.1% of events, 2.7+/-2.7 missed pills), followed by vomiting and diarrhoea. 81.5% of women chose to terminate their pregnancy.

DISCUSSION AND CONCLUSION

The GRECO study, despite its limitations (retrospective collection of missed pills data, declaratory data) showed that missed pills, even once, were the most common reason for oral contraceptive failure. The most frequent decision was the termination of pregnancy.

The vaginal ring and transdermal patch: new methods of contraception

The most common method of reversible contraception used worldwide is the intrauterine device. However, in the Asia–Pacific the combined oral contraceptive pill and condoms, methods of contraception that require a high degree of day-to-day user compliance, are more popular. The combined vaginal ring and transdermal patch have been developed to overcome the need for daily compliance associated with combined pill use. They have the added advantages of non-oral delivery, thus avoiding gastro-intestinal interference with absorption, and in addition there is no hepatic first-pass effect. Both have been available internationally for some years and offer an alternative to the combined pill. This article reviews and summarises published data on these new methods.

Clinical performance and menstrual bleeding patterns with three dosage combinations of a Nestorone progestogen/ethinyl estradiol contraceptive vaginal ring used on a bleeding-signaled regimen

OBJECTIVE

We examined the clinical performance of contraceptive vaginal rings (rings) delivering Nestorone (NES) progestin and ethinyl estradiol (EE). Ring removal times were signaled by menstrual events. Bleeding patterns, adverse events, patterns of use and continuation rates were the principal parameters evaluated.

METHODS

In a two-stage 6-month trial, subjects were randomized to use rings releasing 50 microg/day of NES and either 10 (50/10) or 20 (50/20) microg/day of EE. Subjects were to keep rings continuously in situ until menstrual bleeding or prolonged spotting-signaled removal. Reinsertion was to occur 96 h later. After the randomized stage, an open-label 6-month trial of rings releasing 150 microg/day of NES and 15 microg/day of EE (150/15) began with the same menstrually signaled regimen.

RESULTS

Two-hundred forty-six subjects participated in the trial. Six-month pregnancy rates ranged by ring dose from 1.3 to 3.9 per 100. For each ring dose combination, 6-month continuation rates were above 80 per 100. Bleeding and spotting (B+S) days in women with the 50 microg/day NES rings were similar in number to those experienced by cycling women not using contraception. Nevertheless, in the initial 90 days, fewer B+S days were reported by subjects with the 50/20 ring than by subjects with the 50/10 ring (p < .05). Throughout the trial, subjects using the 150/15 ring reported significantly fewer B+S episodes than did subjects with either 50 microg/day NES ring.

CONCLUSION

Combined contraceptive rings used with a bleeding-signaled regimen led to few terminations attributed to bleeding problems and to acceptable continuation rates. The 150/15 ring appeared to induce fewer bleeding problems than did the lower-dose NES combination rings, but no important difference in 6-month continuation rates among the three doses was noted.

Applying motivational interviewing to contraceptive counseling: ESP for clinicians

Healthcare providers are in a unique position to address women's risk of unintended pregnancy and sexually transmitted infections (STIs), yet evidence for effective counseling strategies is limited. One approach to developing effective contraceptive counseling methods may be the application of theory-based behavior counseling models. One such model, motivational interviewing (MI), is a promising approach for addressing risk-taking behaviors of many kinds. We propose application of MI to contraceptive counseling. This process, ESP, involves Exploring discrepancies between pregnancy intention and contraceptive use and between risk of STIs and condom use, Sharing information and Promoting behaviors to reduce risk. This model emphasizes the importance of identifying discrepancies between goals and behaviors and supporting women's confidence in using appropriate contraceptive methods

Initiating contraception in sexually transmitted disease clinic setting: a randomized trial

OBJECTIVE

Our purpose was to determine the effectiveness of sexually transmitted disease (STD) clinic-initiated contraceptive care.

STUDY DESIGN

Nonpregnant women (n=877) attending an urban STD clinic using either no contraception or only condoms were randomly assigned to either an intervention (n=437) or control group (n=440). Both groups received condoms with spermicide and a referral list of primary care providers (PCP) for ongoing reproductive health care, and the intervention group also received enhanced contraceptive counseling, initial provision of contraception, and facilitated referral to a PCP. Outcomes measured at 4-, 8-, and 12-month follow-up were transition to a PCP, effective contraceptive use (ECU), interval pregnancy, and STD.

RESULTS

The median time to PCP transition was 79 days for the intervention group versus 115 days for the control group (P=.007). Rates of ECU were higher for the intervention group than for control group at the 4-month visit (50% vs 22%, P<.0001) as well as the 8-month visit, although in the intervention group ECU diminished over the course of the study. During follow-up, pregnancy outcomes were documented for 229 women (26.1%), for an overall pregnancy rate of 38.2 per 100 person-years of follow-up. Of the 159 pregnancies defined by patient self-report, 153 (96.2%) were described as unintended and 32 (20%) resulted in a therapeutic abortion. The pregnancy rate was 15% lower in the intervention (105/437, 24.0%) than the control group (124/440, 28.2%) (P=.16), but this difference was not statistically significant.

CONCLUSION

The intervention helped women transition to a PCP and initiate ECU but did not significantly reduce the pregnancy rate. More intensive interventions are needed to prevent unintended pregnancy in this high-risk population.

Factors associated with adolescent pregnancy- a sample of Taiwanese female adolescents

This study was designed to explore the factors that differentiate sexually experienced teenagers who become pregnant from those who do not. The study examined the differences between pregnant and never-pregnant female adolescents in personal background characteristics, family characteristics, substance use, contraceptive attitude, contraceptive knowledge, contraceptive self-efficacy, sexual history, and effective contraceptive use. Sexually experienced but never-pregnant female adolescents were selected from two vocational high schools. Pregnant adolescents were recruited by convenience sampling from obstetric clinics and health stations in Tainan City, Taiwan. Multiple logistic regression analysis identified six factors associated with pregnancy: poor contraceptive knowledge, poor contraceptive self-efficacy, low socioeconomic status, low effective contraceptive use scores, more frequent sexual intercourse, and older age. The results of this study provide health professionals with information to develop more-effective prevention and intervention programs to reduce adolescent pregnancy. The results also could be used as a reference for related research and policy development in other countries.

Adolescents' attitudes and experiences regarding levonorgestrel 100 mcg/ethinyl estradiol 20 mcg

STUDY OBJECTIVE

Oral contraceptive pills (OCs) are a commonly prescribed method of birth control for sexually experienced adolescents. The purpose of the current study was to describe anticipated parental involvement and adolescent compliance with pill taking, and to describe experiences with a 20-mcg OC regarding satisfaction and side effects after six cycles.

DESIGN

Anticipated parental involvement and anticipated compliance, and experiences with an OC, were assessed at baseline, and after the first and sixth cycles during a clinical trial of oral contraceptives, which required parental consent.

SETTING

Three adolescent medicine clinics in New York, NY; Cincinnati, OH; and San Juan, Puerto Rico.

PARTICIPANTS

The sample consisted of 43 female adolescents with a mean age of 17 years.

RESULTS

The majority of adolescents living with a parent anticipated parental involvement, and few adolescents anticipated difficulties with consistent pill taking. For two side effects (weight and mood changes), more than 30% of the adolescents anticipated the occurrence or worsening of side effects. However, few adolescents actually experienced increases in any of the nine side effects assessed. Ninety-seven percent of adolescents in this trial reported being satisfied with a 20-mcg OC.

CONCLUSIONS

Health care providers can assess adolescents' anticipated difficulties with compliance with daily pill taking, and desire for help from their parents. This information can be incorporated into counseling to promote consistent and correct use.

Contraceptive applications of estrogen

Estrogens are a primary component of several contraceptive methods: combined oral contraceptive pills, a combined injectable contraceptive, the combined contraceptive vaginal ring, the combination transdermal contraceptive patch, and combined emergency contraceptive pills. Contraceptive formulations that contain estrogen are referred to as combined contraceptives because they also contain some form of progestin. This article reviews the contraceptive methods containing estrogen, beginning with a discussion of combined oral contraceptive pills. Formulations and clinical management, mechanisms of action, noncontraceptive benefits of use, therapeutic uses in addition to contraception, side effects, contraindications to use, and drug-drug interactions are described. Information follows about the newer combined contraceptive products including the injection, vaginal ring, and patch. Finally, combined emergency contraceptive pills are reviewed. Thorough knowledge of the contraceptive methods containing estrogen enables clinicians to provide expert care for women using these products.

Health benefits of oral contraceptives

A sizeable literature corroborates the multiple health benefits of oral contraceptive use. The first estrogen/progestin combination pills were marketed to treat a variety of menstrual disorders. Although currently used oral contraceptives no longer carry FDA-approved labeling for these indications, they remain important therapeutic options for a variety of gynecologic conditions. Well-established gynecologic benefits include a reduction in dysmenorrhea and menorrhagia, iron-deficiency anemia, ectopic pregnancy, and PID. Although older, higher-dose pills reduced the incidence of ovarian cysts, low-dose pills suppress follicular activity less consistently. Nevertheless, cycle-related symptoms, including functional cysts, dysmenorrhea, chronic pelvic pain, and ovulation pain (mittelschmerz), generally improve. Women with polycystic ovary syndrome note improvement in bleeding patterns and a reduction in acne and hirsutism. Symptoms from endometriosis also improve with oral contraceptive therapy. Current data suggest that oral contraceptive therapy increases bone density and that past use decreases fracture risk. Oral contraceptives also improve acne, a major health concern of young women. Oral contraceptives provide lasting reduction in the risk of two serious gynecologic malignancies--ovarian and endometrial cancer. The data with respect to ovarian cancer are compelling enough to recommend the use of oral contraceptives to women at high risk by virtue of family history, positive carrier status of the BRCA mutations, or nulliparity, even if contraception is not required. Health care providers must counsel women regarding these benefits to counteract deeply held public attitudes and misconceptions regarding oral contraceptive use. Messages should focus on topics of interest to particular groups of women. The fact that oral contraceptives increase bone mineral density and reduce ovarian cancer is of great interest to women in their forties and helps influence use and compliance in this group. In contrast, the beneficial effects of oral contraceptives on acne resonates with younger women. Getting the good news out about the benefits of oral contraceptives will enable more women to take advantage of their positive health effects.

The oral contraceptive pill: a revolution for sportswomen?

OBJECTIVES

To determine the effects of the oral contraceptive pill (OCP) on skeletal health, soft tissue injury, and performance in female athletes.

METHODS

A literature review was performed using literature retrieval methods to locate relevant studies.

RESULTS

Most female athletes primarily choose to use the OCP for contraceptive purposes, but cycle manipulation and control of premenstrual symptoms are secondary advantages of its use. The effect of the OCP on bone density in normally menstruating women is unclear, with some studies reporting no effect, others a positive effect, and some even a negative effect. The OCP is often prescribed for the treatment of menstrual disturbances in female athletes, and improvements in bone density may result. Whether the OCP influences the risk of stress fracture and soft tissue injuries is not clear from research to date. Effects of the OCP on performance are particularly relevant for elite sportswomen. Although a reduction in Vo2MAX has been reported in some studies, this may not necessarily translate to impaired performance in the field. Moreover, some studies claim that the OCP may well enhance performance by reducing premenstrual symptoms and menstrual blood loss. A fear of weight gain with the use of the OCP is not well founded, as population studies report no effect on weight, particularly with the lower dose pills currently available.

CONCLUSIONS

Overall, the advantages of the pill for sportswomen would appear to outweigh any potential disadvantages. Nevertheless, there is individual variation in response to the OCP and these should be taken into account and monitored in the clinical situation. Women should be counselled as to the range of potential benefits and disadvantages in order to make an informed decision based on individual circumstances.

Immediate recall of oral contraceptive instructions: implications for providers

OBJECTIVE

The object of the study was to determine the patient characteristics associated with inadequate recall of oral contraceptive pill-taking instructions.

STUDY DESIGN

Sexually active women aged 13 to 40 years (n = 150) attending university-based family planning clinics completed anonymous self-report measures that assessed demographic and reproductive characteristics, understanding of pill-taking instructions, and contraceptive compliance. Logistic regression was used to determine factors associated with inadequate recall for the sample, stratified by minority versus nonminority women.

RESULTS

Minority women with inadequate recall were almost 6 times more likely than minority women with adequate recall not to know the name of the prescribed oral contraceptive and were 3 times more likely to have less than a high school education. In addition there were 1-fold and 2-fold increases in likelihood of inadequate recall as certainty of pill-taking instructions and general oral contraceptive knowledge, respectively, decreased. Inadequate recall was associated with poor compliance.

CONCLUSION

Women with inadequate recall may be identified at the conclusion of their visit so that interventions to enhance their pill-taking skills can be provided.

Combining qualitative with quantitative approaches to study contraceptive pill use

According to large-scale studies, oral contraceptive users become pregnant at rates that exceed ideal use failure rates. It is thought that a major cause is missed pills, but current research on consistent contraceptive pill taking is characterized by inadequate measures and a failure to investigate women's thinking about their own patterns of use. The purpose of this study was to gain some understanding about women's interpretations of consistency in their own pill taking through combining qualitative with quantitative data. The study was conducted in China, where contraception is free and widely available. Five urban and five rural oral contraceptive users were followed for up to three pill-taking cycles during 1996 for a total of 759 person-days. Consistency of pill taking was measured with electronic data obtained from a new blister package made by Anderson Clinical Technologies (Elmhurst, IL). Data from these devices were reviewed and interpreted by the study participants during in-depth private interviews. The users' reasons for missing pills included disruptions in their daily routines, their husband's absence, spotting, and trouble implementing the family planning program's instructions to take one pill per day for 22 days and start the next cycle on the fifth day of menses. One user gave these reasons for two cycles but denied missing numerous pills in her third cycle. Data from a series of four questionnaires showed that most demographic, psychosocial, and service system characteristics were not related to missed pills. However, results suggested that the daily routines of rural living may make consistent use more likely and that instructions for taking the pill may be associated with prolonged pill-free intervals and skipping pills during episodes of spotting. Three of the 10 women were at increased risk of pregnancy during the study period because of their pill-taking pattern. We concluded that the combination of qualitative with quantitative data enhances understanding of contraceptive use. Women themselves offer plausible reasons for their use behaviors. Listening to women could be useful in improving programs.