The intrauterine device and pelvic inflammatory disease: the Women's Health Study reanalyzed

[Critical reading of analytical observational studies]

Analytical observational studies provide very important information about real-life clinical practice and the natural history of diseases and can suggest causality. Furthermore, they are very common in scientific journals. The aim of this article is to review the main concepts necessary for the critical reading of articles about radiological studies with observational designs. It reviews the characteristics that case-control and cohort studies must have to ensure high quality. It explains a method of critical reading that involves checking the attributes that should be evaluated in each type of article using a structured list of specific questions. It underlines the main characteristics that confer credibility and confidence on the article evaluated. Readers are provided with tools for the critical analysis of the observational studies published in scientific journals.

Women's knowledge about intrauterine contraception

OBJECTIVES

To survey knowledge and attitudes about intrauterine contraception among reproductive-aged women in the area of Saint Louis, Missouri.

METHODS

We mailed an eight-page written survey to 12,500 randomly selected households in the St. Louis area that asked English-literate, reproductive-aged, adult women to respond. The survey asked about obstetric and contraceptive history and effectiveness of contraceptive methods, as well as appropriate candidates for, side effects of, and perceived risks of intrauterine contraception. The results from 1,665 (13.3%) returned surveys were weighted for the analysis, which included descriptive statistics and polynomial logistic regression.

RESULTS

Almost 8% of respondents were currently using or had previously used intrauterine contraception, and use was higher in women who reported discussing the method with their health care provider (adjusted odds ratio [OR] 13.4, 95% confidence interval [CI] 6.5-27.8). Sixty-one percent of respondents underestimated the effectiveness of intrauterine contraception, and up to one half of survey respondents were unable to correctly answer knowledge questions about intrauterine contraception use and safety. An additional 11%-36% of respondents indicated concern that intrauterine contraception is associated with complications such as infection, infertility, and cancer. Current and past intrauterine contraception users were more likely to be knowledgeable about intrauterine contraception. Women who were currently using intrauterine contraception were more likely to correctly estimate the effectiveness of intrauterine contraception (adjusted OR 7.6, 95% CI 3.2-18.0).

CONCLUSION

Reproductive-aged women's specific knowledge of the benefits and risks of intrauterine contraception is limited. More educational interventions are needed to increase women's knowledge about the effectiveness and benefits of intrauterine contraception.

LEVEL OF EVIDENCE

II.

Pitfalls of research linking the intrauterine device to pelvic inflammatory disease

Correctly diagnosing pelvic inflammatory disease (PID) using noninvasive clinical criteria remains challenging. Current guidelines for initiating treatment, based on minimal criteria (sensitive but not specific), are justified for public health purposes but inadequate and misleading for scientific purposes. Previous research on the link between the intrauterine device (IUD) and PID was controversial and subject to many limitations. Even today, these limitations still exist and include uncertainty of the PID diagnosis, unfair contraceptive comparisons, selection and diagnostic bias, and confounding. For example, IUD users are on heightened alert for PID relative to users of other methods. In addition, IUD users with pelvic pain may be more likely to seek physician consultation and consequently receive a PID diagnosis (true-positive or false-positive). Confounding factors such as higher coital frequency, multiple sexual partners, and low condom use may explain any finding that shows a higher PID rate among IUD users compared with other contraceptive users. Good evidence on how or whether the IUD changes the etiology of PID is lacking. In the past 10 years, use of the intrauterine device in the United States has increased markedly. Thus today, researchers may now have sufficient population-level exposure (IUD use) and disease (PID) to search for a connection and repeat past mistakes. Any new findings using observational research should be interpreted with caution. More rigorous research designs may not be pragmatic or feasible.

Adolescent and young adult women's knowledge of and attitudes toward the intrauterine device

BACKGROUND

This study aimed to assess adolescent (aged 14-18 years) and young adult (aged 19-24 years) women's knowledge of and attitudes toward intrauterine devices (IUDs) before and after a brief educational intervention.

STUDY DESIGN

We administered a 43-item survey to 144 women aged 14-24 years, with half in each age category. The survey assessed knowledge of and attitudes toward IUDs, and incorporated a 3-min educational intervention about IUDs. Predictors for knowledge of and attitudes toward the IUD were examined using logistic regression.

RESULTS

Forty percent of participants had heard of the IUD. Having ever heard of the IUD was associated with age >18 years [adjusted odds ratio (OR)=5.7; 95% confidence interval (95% CI)=2.1-15.7], a higher level of maternal education (adjusted OR=4.5; 95% CI=1.5-13.3) and a history of voluntary sexual intercourse (adjusted OR=4.9; 95% CI=1.0-23.5). Of those who had heard of the IUD previously, 37.5% reported a positive attitude toward the IUD before the intervention. After the educational intervention, 53.5% of all participants reported a positive attitude toward the IUD, with both adolescent and young adult women having similarly positive attitudes (51.4% vs. 55.6%, p=.62). This positive attitude was associated only with a history of voluntary sexual intercourse (adjusted OR=5.2; 95% CI=1.3-21.1). The characteristics of the IUD that the participants strongly liked and disliked were rated similarly by the two age groups. However, more adolescent women considered the privacy of the IUD and the ability to use the copper IUD for 10 years as positive characteristics.

CONCLUSION

Most young women were unaware of IUDs but were likely to think positively about IUDs after being educated about them. Demographic and reproductive health history did not predict attitude; thus, all young women should be offered education about IUDs.

Use of IUD and subsequent fertility — follow-up after participation in a randomized clinical trial

PURPOSE

Although the IUD has been a contraceptive method for about 50 years, how it affects subsequent fertility remains controversial. The aim of our study was to examine time to pregnancy, pregnancy outcome and the need for infertility workup in a cohort of previous copper IUD users.

MATERIALS AND METHODS

From May 1993 to April 1995, 957 women were included in a prospective cohort IUD study in the city of Trondheim, Norway. From this randomized clinical trial, we identified 205 women eligible for study participation. Group A comprised 109 women who removed their IUD for purposes of planning to become pregnant, while Group B comprised 96 women who became pregnant or planned pregnancy after a complicated IUD use. Data were collected through a postal questionnaire. All information from the questionnaires was validated against data kept in the medical record at the general practitioner's office or in the hospital record of women who became pregnant or started an infertility workup. All analyses were done using SPSS.

RESULTS

In Group A, 93.6% (102/109) of the women became pregnant. Time to conception was unaffected by parity order, duration of use and age at time for removal of the IUD. Among the seven women who did not conceive, four women cancelled pregnancy plans, while three women started an infertility workup. The distribution of intra-/extrauterine pregnancies did not differ between Groups A and B. However, significantly more pregnancies were terminated as induced abortions in Group B. The two women (2%) who did not conceive in Group B did not start an infertility workup.

CONCLUSION

In line with results from other studies, there is no evidence that prior use of a copper-containing IUD increases the risk for impaired fertility regardless of the reason for removal.

Gynecologic health care for the adolescent solid organ transplant recipient

The improved survival of pediatric recipients of solid organ transplants has prompted increased attention to quality of life issues. These include attainment of normal growth, involvement in romantic relationships, and the desire to control fertility. As an increasing number of adolescent transplant recipients are involved in normal social and sexual relationships, they require careful attention to their gynecologic and reproductive health care needs. Anticipating the onset of sexual activity before it occurs may help to prevent a mistimed pregnancy by providing or prescribing condoms and emergency contraception in advance. In addition, many transplant recipients can safely use the currently available methods of hormonal contraception provided there is careful attention to organ function, other medical problems, and concurrently prescribed medications. In adolescent patients, issues such as pubertal development and menstruation, contraception, and routine gynecologic health care are typically addressed by the patient's primary care provider. However, the complexity of the adolescent transplant recipient's medical care necessitates close collaboration among all health care providers caring for the patient. This review is intended to help the transplant team better understand the gynecologic health care needs and treatment options of their adolescent patients.

Gynecologic issues of the adolescent female solid organ transplant recipient

Advances in the field of transplant medicine are providing adolescent recipients with continual improvements in health and quality of life. With expanding opportunities for normal social and sexual relationships, adolescents require careful attention to their gynecologic and reproductive health (Box 1). Medical considerations vary depending on the type of organ transplanted, underlying and comorbid conditions, and current medication use. Most adolescent girls achieve menarche, however, and irregular cycles should be evaluated and managed with the same considerations applied to healthy young women. The management of menstrual disorders frequently uses hormonal contraceptive methods. Many transplant recipients also are sexually active and require a contraceptive method to prevent a mistimed pregnancy. With careful attention to organ function, other medical problems, and concurrently prescribed medications, many transplant recipients can use safely the currently available methods of hormonal contraception.

A randomized controlled trial of coil removal prior to treatment of pelvic inflammatory disease

OBJECTIVE

To evaluate the effects of removing coils on the treatment of mild and moderate pelvic inflammatory disease (PID).

METHODS

Of 126 women who had mild to moderate PID during coil usage, 60 were treated following coil removal and 66 without. Clinical symptoms, findings of gynecologic examination, erythrocyte sedimentation rates (mm/h), leukocyte counts (mm(-3)) were recorded before and after treatment and recovery rates of symptoms and findings were compared with Chi-square and Fisher's absolute Chi-square tests. Student's t-test was used for the comparison of mean sedimentation rates and leukocyte counts.

RESULTS

Recovery rates of pelvic pain, purulent vaginal discharge, dysuria/frequency and dyspareunia and clinical improvements in abdominal and cervical tenderness were significantly higher (P<0.05) in the coil removed group.

CONCLUSIONS

Removing the coil before medical therapy, increases the rates of clinical improvement in mild to moderate PID.

Bias and causal associations in observational research

Readers of medical literature need to consider two types of validity, internal and external. Internal validity means that the study measured what it set out to; external validity is the ability to generalise from the study to the reader's patients. With respect to internal validity, selection bias, information bias, and confounding are present to some degree in all observational research. Selection bias stems from an absence of comparability between groups being studied. Information bias results from incorrect determination of exposure, outcome, or both. The effect of information bias depends on its type. If information is gathered differently for one group than for another, bias results. By contrast, non-differential misclassification tends to obscure real differences. Confounding is a mixing or blurring of effects: a researcher attempts to relate an exposure to an outcome but actually measures the effect of a third factor (the confounding variable). Confounding can be controlled in several ways: restriction, matching, stratification, and more sophisticated multivariate techniques. If a reader cannot explain away study results on the basis of selection, information, or confounding bias, then chance might be another explanation. Chance should be examined last, however, since these biases can account for highly significant, though bogus results. Differentiation between spurious, indirect, and causal associations can be difficult. Criteria such as temporal sequence, strength and consistency of an association, and evidence of a dose-response effect lend support to a causal link.

Use of copper intrauterine devices and the risk of tubal infertility among nulligravid women

BACKGROUND

Previous studies of intrauterine devices (IUDs), many of which are no longer in use, suggested that they might cause tubal infertility. The concern that IUDs that contain copper--currently the most commonly used type--may increase the risk of infertility in nulligravid women has limited the use of this highly effective method of birth control.

METHODS

We conducted a case-control study of 1895 women recruited between 1997 and 1999. We enrolled 358 women with primary infertility who had tubal occlusion documented by hysterosalpingography, as well as 953 women with primary infertility who did not have tubal occlusion (infertile controls) and 584 primigravid women (pregnant controls). We collected information on the women's past use of contraceptives, including copper IUDs, previous sexual relationships, and history of genital tract infections. Each woman's blood was tested for antibodies to Chlamydia trachomatis. We used stratified analyses and logistic regression to assess the association between the previous use of a copper IUD and tubal occlusion.

RESULTS

In analyses involving the women with tubal occlusion and the infertile controls, the odds ratio for tubal occlusion associated with the previous use of a copper IUD was 1.0 (95 percent confidence interval, 0.6 to 1.7). When the primigravid women served as the controls, the corresponding odds ratio was 0.9 (95 percent confidence interval, 0.5 to 1.6). Tubal infertility was not associated with the duration of IUD use, the reason for the removal of the IUD, or the presence or absence of gynecologic problems related to its use. The presence of antibodies to chlamydia was associated with infertility.

CONCLUSIONS

The previous use of a copper IUD is not associated with an increased risk of tubal occlusion among nulligravid women whereas infection with C. trachomatis is.

Intrauterine devices and pelvic inflammatory disease: meta-analyses of published studies, 1974-1990

We conducted a meta-analysis of 36 papers published between 1974 and 1990 to estimate the effects of intrauterine device (IUD) use and Dalkon Shield use, in particular, on pelvic inflammatory disease (PID). The number of women studied in each report ranged from 50 to 26,507. For general IUD use, analyses were separated by type of PID (symptomatic or asymptomatic) because of extreme rate-ratio heterogeneity across studies. Dalkon Shield rate ratios were more homogeneous and were considered in a single meta-regression. There was substantial heterogeneity, however, in all three meta-regressions; the rate-ratio estimates ranged from 0.51 to 12 for IUD use and symptomatic PID, from 1.0 to 132 for IUD use and asymptomatic PID, and from 0.32 to 28 for Dalkon-Shield use and PID. This heterogeneity appeared to be due to differences in reference groups, study populations, and characteristics of study design. We observed consistent, positive associations of IUD use with both symptomatic and asymptomatic PID. These associations were largest for the Dalkon Shield.

The "boom and bust phenomenon": the hopes, dreams, and broken promises of the contraceptive revolution

The "boom and bust phenomenon" is a pattern that has emerged in the development, introduction, and delivery of a number of significant new contraceptive products in the United States. When a new contraceptive product is introduced with great promise and publicity, it usually experiences a "boom" during which sales, demand, and expectations are high. This boom is often followed by a "bust" phase during which a product does not live up to expectations, initial excitement falls off, and a drop in sales and use ensues. The boom and bust phenomenon goes to the heart of what some have referred to as the failed promise of the contraception revolution by creating obstacles to significant expansion of contraceptive choice in the United States. Case studies of oral contraceptives, intrauterine devices, and Norplant(R) are used to illustrate the boom and bust phenomenon and the effect it has had in shaping the direction of advances in contraceptive technology.

Modern intra-uterine devices

Modern intrauterine devices (IUDs) provide effective, safe and long-term contraception and could be recommended to most women. The mechanism of action of an IUD is still not fully understood, but most recent research suggests that copper-IUDs as well as hormone-releasing intrauterine systems (IUSs) prevent conception. In women in mutually monogamous relationships the risk of PID is low and related to the insertion procedure. IUD/IUS use should be discouraged if there is a suspicion of increased risk of sexually transmitted disease. The risk of ectopic pregnancy is extremely low if modern, highly effective IUDs/IUSs are used. Copper-IUDs increase menstrual blood loss by around 50%, whereas hormone-releasing IUSs substantially reduce menstrual blood loss. Careful patient selection and counselling are the most important tools in order to provide acceptable and safe IUD use.

Intrauterine contraception in nulligravid vs parous women

The performance of MLCu-250 IUDs inserted in 525 nulligravid women was studied for four years and is compared to the results obtained in the same period from 2770 parous women using TCu-200, 7Cu-200 and Nova-T IUDs. In every case the choice of the particular IUD model took into account hysterometry and diameter of the inner cervical orifice in order to aim at the highest theoretical efficacy. The MLCu-250 in nulligravid women produced failure and expulsion rates below those of the other models in parous users; no difference was observed in the case of removal because of bleeding or pain. Finally, there was no case of subsequent infertility or pelvic inflammatory disease (PID) recorded among nulliparae. These results suggest that an adequate choice of the IUD model for nulliparous women with low risk of PID gives as reliable results as in multiparous women.

The Dalkon syndrome--a rare condition?

A patient who presented acutely with severe pelvic sepsis related to Dalkon shield is reported. Although the Dalkon syndrome has been described (Tatum HJ, Connell EB. Intrauterine contraception. Duvant: Creative Informatics, 1985) the term is not widely used and controversy surrounds this condition. However, the condition may still present to the modern day gynaecologist.

The pathology of intra-uterine contraceptive devices

The IUCD is a simple and effective way of producing contraception without the need for patient compliance. It is not rendered ineffective by other drugs, as may be steroid contraceptives, and its side-effects, for carefully selected patients, are considered by most practitioners to be acceptably low (Van Kets et al. 1989).

What we have learned from recent IUD studies: a researcher's perspective

Many studies published on intrauterine devices (IUDs) during the last six years have consistently reported findings in favor of IUD use. Notable among these findings are: IUDs are not abortifacients; newly developed IUDs are highly effective and the efficacy is long-lasting; IUDs can be safely used by most lactating women, with lower removal rates attributable to bleeding and/or pain; and immediate postplacental IUD insertion reduces the risk of expulsion usually associated with postpartum insertion. Most importantly, in apparent contrast to results often reported in the late 1960s through the early 1980s, recent findings show that IUDs per se, especially the medicated ones, are not associated with an increased risk of pelvic inflammatory disease (PID), nor are they associated with an increased risk of ectopic pregnancy or subsequent infertility. There are still issues concerning IUD use that are controversial in spite of numerous studies. Should some of the contraindications currently listed for IUD use be modified according to the newer findings? Is the risk of uterine perforation increased when the IUD is inserted in lactating women? Do IUD tails increase the risk of PID? Does oral use of antibiotics at IUD insertion help prevent postinsertion PID? There are also issues that have not been sufficiently addressed and more information from empirical studies is needed. These include: the effect of the insertor's skill on IUD performance; IUD use in nulliparous as well as in older women; the relationship between IUD use and chlamydia infection; and long-term IUD use and safety, including actinomycosis, etc. Answers are also needed by administrators facing difficult programmatic decisions. For instance, should programs involving massive IUD removal be implemented as many IUD-wearing women are approaching or passing menopause? Similarly, are large programs to remove less-effective devices and replace them with newer and more effective IUDs advisable? This article reviews the state-of-the-art findings from recent IUD studies on the above issues.

Another look at the Dalkon Shield: meta-analysis underscores its problems

Numerous non-comparative clinical trials of the Dalkon Shield appear to provide ample evidence that the Dalkon Shield was an effective IUD; they seem to yield little evidence that it was a dangerous device, nor markedly different from its contemporaries. Equating the performance of the Dalkon Shield IUD to that of the Lippes Loop or of Copper IUDs is erroneous, however, with respect to rates of pregnancy, expulsion, pelvic infection, septic abortion, death with the device in situ, and tubal infertility. Randomized studies show the Dalkon Shield had approximately double the pregnancy rates of the Lippes Loop D or Copper IUDs (P < .05) and a significantly lower expulsion rate. These differences coupled together with the distinguishing multifilament tail of the Dalkon Shield underlay the higher rates of pregnancy complications, including septic abortions with the device in situ and deaths, associated with the Shield. A five-fold increased risk of hospitalized pelvic infection among Dalkon Shield users found in the Women's Health Study resulted not from ascertainment bias, but was related to the fact that Dalkon Shield users had more severe hospitalized PID than did other hospitalized women with PID and IUD use. Following cessation of distribution and of use of the Dalkon Shield, and following the FDA's recommendation to remove IUDs in case of pregnancy, there have been no deaths reported among pregnant American women with an IUD in situ in a 15-year period. Neither the IUDs of today nor those in use during 1970-1974 are equitable to the Dalkon Shield [corrected].

Contraception and sexually transmitted diseases: interactions and opportunities

Today "safe sex" means protection from both unintended pregnancy and sexually transmitted disease and human immunodeficiency virus. These parallel complications of sexual activity have serious biologic and clinical sequelae that should be considered at the time of contraceptive selection. In addition, there is ongoing debate regarding potential interactions between antibiotic intervention and contraceptive steroids. This article assesses the impact of hormonal contraception, spermicides, barrier methods, intrauterine devices, and douching on the pathogenesis of sexually transmitted disease and the human immunodeficiency virus infection. It discusses the direct and indirect effects of contraception methods on clinical physiology and host immune responses while also considering the possible consequences on maternal and infant health if pregnancy results from the use of ineffective contraception. Counseling and care for both family planning and infectious disease protection must be provided to all sexually active individuals.

Intrauterine contraceptive device and pelvic inflammatory disease

Comprehensive, mainly epidemiological data has helped us to recognize the strongest risk factors of pelvic inflammatory disease during intrauterine contraceptive device use. These are user's exposure to sexually transmitted diseases, young age and insertion of the device. Moreover, parity of the user and type of device may affect the risk of pelvic infection.

Pelvic inflammatory disease: risk factors and microbial etiologies

OBJECTIVE

To review the risk factors and microbial etiologies of pelvic inflammatory disease (PID).

DATA SOURCES

Include 77 current and historical references on PID, PID risk factors, and sexually transmitted diseases.

STUDY SELECTION

34 studies that address specific research questions.

DATA EXTRACTION

Data were used from studies whose methodologies are discussed.

DATA SYNTHESIS

This review identifies research problems regarding the definition, diagnosis, and identification of microbial profiles and risk factors of PID.

CONCLUSIONS

More reliable diagnostic criteria for the varied clinical presentations of this polymicrobial infection are needed. PID is a disease with multiple, interrelated risks. Education is an important nursing intervention.

Is users' knowledge about contraceptives adequate? A case study of Finnish IUD users

Intrauterine contraceptive devices (IUDs) are popular: in Finland, in 1987, about 25% of women of childbearing age used them. We studied Finnish women's knowledge about contraindications for and side-effects of IUD use, with emphasis on current users. In December 1987-January 1988, a postal questionnaire was sent to a random sample of 1000 women of childbearing age, in Uusimaa province, which includes the capital, Helsinki. After three reminders, the response rate was 84%. We compared the answers of current and past users and nonusers of IUDs, and analyzed the associations between IUD use, education, age, and knowledge about side-effects. In contrast to the recommendations for use and information to be given to the contraceptive users, a substantial proportion of current IUD users assumed there are few limitations for IUD use. Some side-effects possibly leading to severe consequences were not considered to be connected with IUD use, not even by users. Although risk of infection was a quite well known fact, infertility was seldom associated with IUD use, and 22% of current IUD users did not associate ectopic pregnancy with IUDs. The results thus suggest that contraceptive counseling is not fully adequate and should receive more attention.

Was the Dalkon Shield a safe and effective intrauterine device? The conflict between case-control and clinical trial study findings

OBJECTIVE

To compare the findings of the case-control and cohort studies used to indict the Dalkon Shield (A.H. Robins Company, Inc., Richmond, VA) with the findings of the Dalkon Shield clinical trials.

DATA IDENTIFICATION

All published reports on the Dalkon Shield were identified through MEDLARS system (United States National Library of Medicine) searches and by cross checking all references in these reports. The same approach was used to identify all case-control and cohort studies of the purported relationship between intrauterine devices (IUDs) and pelvic inflammatory disease (PID).

STUDY SELECTION

Only studies of interval patients that included 50 or more women and 6 or more months of follow up that computed standard IUD event rates (rates of pregnancy and expulsion and removal for pain and bleeding) were selected for this study. All case-control and cohort studies identified were included except two case-control studies that included women with sterile chronic salpingitis.

RESULTS

The 16 case-control and 2 cohort studies found or suggested that the Dalkon Shield increased the risk of PID. The 71 clinical trials of the Dalkon Shield show that when this device is inserted by an experienced clinician it is a safe and effective contraceptive method, comparable with other IUDs used at the time. There was no evidence of an increased risk of PID found in these clinical trials.

CONCLUSIONS

This study offers convincing evidence that the indictment of the Dalkon Shield was a mistake. Additionally, this study shows that physician skill and experience is far more important to successful IUD insertion than previously recognized, a finding with considerable implications for IUD study designs and for marketing strategies.

Accuracy of recall of use of an intrauterine device

Within a case-control study of the relationship between oral contraceptives and breast cancer, information on other contraceptive practices, including use of an intrauterine device (IUD) was obtained through interviews of study subjects and from the records of gynaecologists. Information from these two sources was compared for 239 women who had ever used an IUD. The results showed that agreement on total duration, number of IUD episodes, and time since first and time since last IUD use was excellent. As approximately 75% of IUDs used were unknown, agreement on brands could not be investigated. Studies investigating the effects of individual types of IUDs should use physician records as an additional source of information.