Adverse health outcomes in women exposed in utero to diethylstilbestrol

BACKGROUND

Before 1971, several million women were exposed in utero to diethylstilbestrol (DES) given to their mothers to prevent pregnancy complications. Several adverse outcomes have been linked to such exposure, but their cumulative effects are not well understood.

METHODS

We combined data from three studies initiated in the 1970s with continued long-term follow-up of 4653 women exposed in utero to DES and 1927 unexposed controls. We assessed the risks of 12 adverse outcomes linked to DES exposure, including cumulative risks to 45 years of age for reproductive outcomes and to 55 years of age for other outcomes, and their relationships to the baseline presence or absence of vaginal epithelial changes, which are correlated with a higher dose of, and earlier exposure to, DES in utero.

RESULTS

Cumulative risks in women exposed to DES, as compared with those not exposed, were as follows: for infertility, 33.3% vs. 15.5% (hazard ratio, 2.37; 95% confidence interval [CI], 2.05 to 2.75); spontaneous abortion, 50.3% vs. 38.6% (hazard ratio, 1.64; 95% CI, 1.42 to 1.88); preterm delivery, 53.3% vs. 17.8% (hazard ratio, 4.68; 95% CI, 3.74 to 5.86); loss of second-trimester pregnancy, 16.4% vs. 1.7% (hazard ratio, 3.77; 95% CI, 2.56 to 5.54); ectopic pregnancy, 14.6% vs. 2.9% (hazard ratio, 3.72; 95% CI, 2.58 to 5.38); preeclampsia, 26.4% vs. 13.7% (hazard ratio 1.42; 95% CI, 1.07 to 1.89); stillbirth, 8.9% vs. 2.6% (hazard ratio, 2.45; 95% CI, 1.33 to 4.54); early menopause, 5.1% vs. 1.7% (hazard ratio, 2.35; 95% CI, 1.67 to 3.31); grade 2 or higher cervical intraepithelial neoplasia, 6.9% vs. 3.4% (hazard ratio, 2.28; 95% CI, 1.59 to 3.27); and breast cancer at 40 years of age or older, 3.9% vs. 2.2% (hazard ratio, 1.82; 95% CI, 1.04 to 3.18). For most outcomes, the risks among exposed women were higher for those with vaginal epithelial changes than for those without such changes.

CONCLUSIONS

In utero exposure of women to DES is associated with a high lifetime risk of a broad spectrum of adverse health outcomes. (Funded by the National Cancer Institute.).

Autoimmune disease incidence among women prenatally exposed to diethylstilbestrol

OBJECTIVE

Animal studies have suggested that prenatal diethylstilbestrol (DES) exposure may alter immune system development and function including antigen self-recognition. A cohort study was conducted to investigate whether prenatal DES exposure might influence the incidence of at least some specific autoimmune diseases in women.

METHODS

A group of women who were and were not prenatally exposed to DES have been followed for more than 25 years for numerous health outcomes including autoimmune disease. To verify diagnoses, medical records or physician abstracts were requested for all women who reported a diagnosis of rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), optic neuritis (ON), and idiopathic thrombocytopenic purpura (ITP). Incidence rates of these autoimmune diseases were compared between women who were and who were not prenatally DES-exposed.

RESULTS

Overall, there was no increase in verified autoimmune disease among DES-exposed women relative to those who were not exposed (RR 1.2; 95% CI 0.7, 2.1). There was, however, a positive association between prenatal DES exposure and RA among women younger than 45 years (RR 4.9; 95% CI 1.1, 21.6) and an inverse association among women who were 45 years and older (RR 0.1; 95% CI 0.01, 0.7).

CONCLUSION

Overall, these data provide little support for an association between prenatal DES exposure and development of autoimmune disease. The implication that such exposure may be related to RA in an unusual age-related manner is based on small numbers of cases and warrants further study.

Breast cancer screening in women exposed in utero to diethylstilbestrol

PURPOSE

To determine if women exposed in utero to diethylstilbestrol (DES) are more likely than unexposed women to receive recommended or additional breast cancer screening examinations.

METHODS

1994 Diethylstilbestrol-Adenosis (DESAD) cohort data are used to assess the degree of recommended compliance of breast cancer screenings found in 3140 DES-exposed and 826 unexposed women. Participants were enrolled at four sites: Houston, Boston, Rochester, and Los Angeles. Logistic regression modeling was used to analyze mailed questionnaire data that included reported frequency over the preceding 5 years (1990-1994) of breast-self examinations (BSEs), clinical breast examinations (CBEs), and mammograms.

RESULTS

DES-exposed women exceeded annual recommendations for CBEs (aOR 2.20, 95% CI, 1.04-4.67) among women without a history of benign breast disease (BBD) compared with unexposed women. There were no other statistically significant differences between exposed and unexposed women who reported performing BSEs, CBEs (<40 years of age), and mammographies, regardless of BBD history.

CONCLUSIONS

The majority of DES-exposed women receive breast cancer screenings at least at recommended intervals, but over two thirds do not perform monthly BSEs. Future efforts should be focused on further educating this and other at-risk populations through mailed reminders and during patient consultations on the benefits of screening examinations.

Urogenital abnormalities in men exposed to diethylstilbestrol in utero: a cohort study

BACKGROUND

Diethylstilbestrol (DES), a synthetic estrogen widely prescribed to pregnant women during the 1940s70s, has been shown to cause reproductive problems in the daughters. Studies of prenatally-exposed males have yielded conflicting results.

METHODS

In data from a collaborative follow-up of three U.S. cohorts of DES-exposed sons, we examined the relation of prenatal DES exposure to occurrence of male urogenital abnormalities. Exposure status was determined through review of prenatal records. Mailed questionnaires (1994, 1997, 2001) asked about specified abnormalities of the urogenital tract. Risk ratios (RR) were estimated by Cox regression with constant time at risk and control for year of birth.

RESULTS

Prenatal DES exposure was not associated with varicocele, structural abnormalities of the penis, urethral stenosis, benign prostatic hypertrophy, or inflammation/infection of the prostate, urethra, or epididymus. However, RRs were 1.9 (95% confidence interval 1.13.4) for cryptorchidism, 2.5 (1.54.3) for epididymal cyst, and 2.4 (1.54.4) for testicular inflammation/infection. Stronger associations were observed for DES exposure that began before the 11th week of pregnancy: RRs were 2.9 (1.65.2) for cryptorchidism, 3.5 (2.06.0) for epididymal cyst, and 3.0 (1.75.4) for inflammation/infection of testes.

CONCLUSION

These results indicate that prenatal exposure to DES increases risk of male urogenital abnormalities and that the association is strongest for exposure that occurs early in gestation. The findings support the hypothesis that endocrine disrupting chemicals may be a cause of the increased prevalence of cryptorchidism that has been seen in recent years.

The association between in utero cigarette smoke exposure and age at menopause

Menopause onset, on average, occurs earlier among women who smoke cigarettes than among women who do not smoke. Prenatal smoke exposure may also influence age at menopause through possible effects on follicle production in utero. Smoking information was obtained from the mothers of 4,025 participants in the National Cooperative Diethylstilbestrol Adenosis (DESAD) Project, a US study begun in 1975 to examine the health effects of prenatal diethylstilbestrol exposure. Between 1994 and 2001, participants provided information on menopausal status. Cox proportional hazards modeling compared the probability of menopause among participants who were and were not prenatally exposed to maternal cigarette smoke. Participants prenatally exposed to maternal cigarette smoke were more likely than those unexposed to be postmenopause (hazard ratio = 1.21, 95% confidence interval: 1.02, 1.43). The association was present among only those participants who themselves had never smoked cigarettes (hazard ratio = 1.38, 95% confidence interval: 1.10, 1.74) and was absent among active smokers (hazard ratio = 1.03, 95% confidence interval: 0.81, 1.31). In this cohort of participants predominantly exposed to diethylstilbestrol, results suggest that prenatal exposure to maternal cigarette smoke may play a role in programming age at menopause. The possibility that active cigarette smoking modifies this effect is also suggested.

Correlation of umbilical cord blood hormones and growth factors with stem cell potential: implications for the prenatal origin of breast cancer hypothesis

Introduction

Prenatal levels of mitogens may influence the lifetime breast cancer risk by driving stem cell proliferation and increasing the number of target cells, and thereby increasing the chance of mutation events that initiate oncogenesis. We examined in umbilical cord blood the correlation of potential breast epithelial mitogens, including hormones and growth factors, with hematopoietic stem cell concentrations serving as surrogates of overall stem cell potential.

Methods

We analyzed cord blood samples from 289 deliveries. Levels of hormones and growth factors were correlated with concentrations of stem cell and progenitor populations (CD34⁺ cells, CD34⁺CD38^- cells, CD34⁺c-kit⁺ cells, and granulocyte–macrophage colony-forming units). Changes in stem cell concentration associated with each standard deviation change in mitogens and the associated 95% confidence intervals were calculated from multiple regression analysis.

Results

Cord blood plasma levels of insulin-like growth factor-1 (IGF-1) were strongly correlated with all the hematopoietic stem and progenitor concentrations examined (one standard-deviation increase in IGF-1 being associated with a 15–19% increase in stem/progenitor concentrations, all P < 0.02). Estriol and insulin-like growth factor binding protein-3 levels were positively and significantly correlated with some of these cell populations. Sex hormone-binding globulin levels were negatively correlated with these stem/progenitor pools. These relationships were stronger in Caucasians and Hispanics and were weaker or not present in Asian-Americans and African-Americans.

Conclusion

Our data support the concept that in utero mitogens may drive the expansion of stem cell populations. The correlations with IGF-1 and estrogen are noteworthy, as both are crucial for mammary gland development.

Secondary sex ratio among women exposed to diethylstilbestrol in utero

BACKGROUND

Diethylstilbestrol (DES), a synthetic estrogen widely prescribed to pregnant women during the mid-1900s, is a potent endocrine disruptor. Previous studies have suggested an association between endocrine-disrupting compounds and secondary sex ratio.

METHODS

Data were provided by women participating in the National Cancer Institute (NCI) DES Combined Cohort Study. We used generalized estimating equations to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for the relation of in utero DES exposure to sex ratio (proportion of male births). Models were adjusted for maternal age, child's birth year, parity, and cohort, and accounted for clustering among women with multiple pregnancies.

RESULTS

The OR for having a male birth comparing DES-exposed to unexposed women was 1.05 (95% CI, 0.95-1.17). For exposed women with complete data on cumulative DES dose and timing (33%), those first exposed to DES earlier in gestation and to higher doses had the highest odds of having a male birth. The ORs were 0.91 (95% C, 0.65-1.27) for first exposure at > or = 13 weeks gestation to < 5 g DES; 0.95 (95% CI, 0.71-1.27) for first exposure at > or = 13 weeks to > or = 5 g; 1.16 (95% CI, 0.96-1.41) for first exposure at < 13 weeks to < 5 g; and 1.24 (95% CI, 1.04-1.48) for first exposure at < 13 weeks to > or = 5 g compared with no exposure. Results did not vary appreciably by maternal age, parity, cohort, or infertility history.

CONCLUSIONS

Overall, no association was observed between in utero DES exposure and secondary sex ratio, but a significant increase in the proportion of male births was found among women first exposed to DES earlier in gestation and to a higher cumulative dose.

American Cancer Society Guideline for human papillomavirus (HPV) vaccine use to prevent cervical cancer and its precursors

The American Cancer Society (ACS) has developed guidelines for the use of the prophylactic human papillomavirus (HPV) vaccine for the prevention of cervical intraepithelial neoplasia and cervical cancer. These recommendations are based on a formal review of the available evidence. They address the use of prophylactic HPV vaccines, including who should be vaccinated and at what age, as well as a summary of policy and implementation issues. Implications for screening are also discussed.

Age at natural menopause in women exposed to diethylstilbestrol in utero

Age at natural menopause is related to several health outcomes, including cardiovascular disease and overall mortality. Age at menopause may be influenced by the number of follicles formed during gestation, suggesting that prenatal factors could influence menopausal age. Diethylstilbestrol (DES), a nonsteroidal estrogen widely prescribed during the 1950s and 1960s, is related to reproductive tract abnormalities, infertility, and vaginal cancer in prenatally exposed daughters but has not been studied in relation to age at menopause. The authors used survival analyses to estimate the risk of natural menopause in 4,210 DES-exposed versus 1,829 unexposed US women based on responses to questionnaires mailed in 1994, 1997, and 2001. DES-exposed women were 50% more likely to experience natural menopause at any given age (hazard ratio = 1.49, 95% confidence interval: 1.28, 1.74). Among women for whom dose information was complete, there were dose-response effects, with a greater than twofold risk for those exposed to >10,000 mg. The causal mechanism for earlier menopause may be related to a smaller follicle pool, more rapid follicle depletion, or changes in hormone synthesis and metabolism in DES-exposed daughters. Age at menopause has been related, albeit inconsistently, to several exposures, but, to the authors' knowledge, this is the first study to suggest that a prenatal exposure may influence reproductive lifespan.

Prenatal Diethylstilbestrol Exposure and Risk of Breast Cancer

It has been hypothesized that breast cancer risk is influenced by prenatal hormone levels. Diethylstilbestrol (DES), a synthetic estrogen, was widely used by pregnant women in the 1950s and 1960s. Women who took the drug have an increased risk of breast cancer, but whether risk is also increased in the daughters who were exposed in utero is less clear. We assessed the relation of prenatal DES exposure to risk of breast cancer in a cohort of DES-exposed and unexposed women followed since the 1970s by mailed questionnaires. Eighty percent of both exposed and unexposed women completed the most recent questionnaire. Self-reports of breast cancer were confirmed by pathology reports. Cox proportional hazards regression was used to compute incidence rate ratios (IRR) for prenatal DES exposure relative to no exposure. During follow-up, 102 incident cases of invasive breast cancer occurred, with 76 among DES-exposed women (98,591 person-years) and 26 among unexposed women (35,046 person-years). The overall age-adjusted IRR was 1.40 [95% confidence interval (95% CI), 0.89-2.22]. For breast cancer occurring at ages >or=40 years, the IRR was 1.91 (95% CI, 1.09-3.33) and for cancers occurring at ages >or=50 years, it was 3.00 (95% CI, 1.01-8.98). Control for calendar year, parity, age at first birth, and other factors did not alter the results. These results, from the first prospective study on the subject, suggest that women with prenatal exposure to DES have an increased risk of breast cancer after age 40 years. The findings support the hypothesis that prenatal hormone levels influence breast cancer risk.

Breast cancer incidence in women prenatally exposed to maternal cigarette smoke

BACKGROUND

Clinical studies show that maternal cigarette smoking reduces pregnancy estrogen levels. Women prenatally exposed to maternal cigarette smoke may, therefore, have a lower breast cancer risk because the fetal mammary gland's exposure to maternal estrogen is decreased. Associations between prenatal maternal cigarette smoke exposure and breast cancer, however, have not been observed in previous case-control studies that relied on exposure assessment after the onset of cancer. At the start of this study, cigarette smoking history was obtained directly from the mother.

METHODS

The National Cooperative DES Adenosis project was a follow-up study of health outcomes in women prenatally exposed to diethylstilbestrol (DES). At the start of the study, women's mothers provided information about cigarette smoking habits during the time they were pregnant with the study participant. In the current study, the breast cancer rates are compared among 4031 women who were or were not prenatally exposed to maternal cigarette smoke. The resultant relative rate (RR) is adjusted for potential confounding by other breast cancer risk factors using Poisson regression modeling.

RESULTS

Fetal exposure to maternal cigarette smoke appeared to be inversely associated with breast cancer incidence (RR = 0.49; 95% confidence interval [CI] = 0.24-1.03). The inverse association was more apparent among women whose mothers smoked 15 cigarettes or fewer per day than among daughters of heavier smokers. There were, however, too few cases to precisely estimate a possible dose-response relationship.

CONCLUSION

These results support the hypothesis that in utero exposure to maternal cigarette smoke reduces breast cancer incidence.

Hypospadias in Sons of Women Exposed to Diethylstilbestrol In Utero

BACKGROUND

Diethylstilbestrol (DES) is a synthetic estrogen that was widely prescribed to pregnant women before 1971. DES increases the risk of breast cancer in women who took the drug and the risk of reproductive tract abnormalities in their offspring. Dutch investigators have reported a 20-fold increase in risk of hypospadias among sons of women who were exposed to DES in utero. We assessed this relation in data from an ongoing study of DES-exposed persons.

METHODS

Several U.S. cohorts of women with documented exposure in utero to DES have been followed by mailed questionnaires since the 1970s. Comparison subjects are unexposed women of the same ages. In 1997, participants were asked about congenital abnormalities in their children. We calculated prevalence odds ratios for the risk of hypospadias in sons of exposed mothers relative to sons of unexposed mothers using generalized estimating equations to adjust for multiple sons per mother and controlling for maternal age at the son's birth.

RESULTS

We obtained data from 3916 exposed and 1746 unexposed women. These women reported a total of 13 liveborn sons with hypospadias (10 exposed, 3 unexposed). The prevalence odds ratio for risk of hypospadias among the exposed was 1.7 (95% confidence interval = 0.4-6.8).

CONCLUSIONS

Our findings do not support a greatly increased risk of hypospadias among the sons of women exposed to DES in utero, as has been previously reported.

Risk of Benign Gynecologic Tumors in Relation to Prenatal Diethylstilbestrol Exposure

OBJECTIVE

To investigate the association between prenatal diethylstilbestrol (DES) exposure and risk of benign gynecologic tumors.

METHODS

We conducted a collaborative follow-up study of women with and without documented intrauterine exposure to DES. We compared the incidence of self-reported ovarian cysts, paraovarian cysts, and uterine leiomyomata confirmed by medical record in DES-exposed and unexposed women.

RESULTS

A total of 85 cases of uterine leiomyomata and 168 cases of ovarian or paraovarian cysts were confirmed histologically. After adjustment for age, no association was found between prenatal DES exposure and ovarian cysts or uterine leiomyomata. Prenatal DES exposure was positively associated with paraovarian cysts.

CONCLUSION

The present results do not support the hypothesis that prenatal DES exposure increases risk of uterine leiomyomata or ovarian cysts. Prenatal DES exposure was associated with an increased risk of paraovarian cysts, but detection bias cannot be ruled out as an explanation of this finding.

Interim guidance for the use of human papillomavirus DNA testing as an adjunct to cervical cytology for screening

Human papillomavirus (HPV) DNA testing was recently approved by the Food and Drug Administration for use as an adjunct to cytology for cervical cancer screening. To help provide guidance to clinicians and patients when using HPV DNA testing as an adjunct to cervical cytology for screening, a workshop was cosponsored by the National Institutes of Health-National Cancer Institute, American Society of Colposcopy and Cervical Pathology (ASCCP), and American Cancer Society. Consensus was reached based on a literature review, expert opinion, and unpublished results from large ongoing screening studies. The conclusions of the workshop were that HPV DNA testing may be added to cervical cytology for screening in women aged 30 years or more. Women whose results are negative by both HPV DNA testing and cytology should not be rescreened before 3 years. Women whose results are negative by cytology, but are high-risk HPV DNA positive, are at a relatively low risk of having high-grade cervical neoplasia, and colposcopy should not be performed routinely in this setting. Instead, HPV DNA testing along with cervical cytology should be repeated in these women at 6 to 12 months. If test results of either are abnormal, colposcopy should then be performed. This guidance should assist clinicians in utilizing HPV DNA testing in an effective manner, while minimizing unnecessary evaluations and treatments.

Cervical cytology screening practices among obstetrician-gynecologists

OBJECTIVE

To estimate the current cervical cytology screening practices of American College of Obstetricians and Gynecologists (ACOG) Fellows, to establish a baseline for tracking future changes in practice.

METHODS

Questionnaires were mailed to a random sample of ACOG Fellows (n = 599) and to a group of Fellows who have regularly participated in past ACOG surveys (n = 409). The questionnaires asked about current cytology screening and evaluation practices and presented clinical practice vignettes with additional questions. Descriptive statistical methods were used to evaluate the responses.

RESULTS

Questionnaires were returned by 651 physicians (64.6%); 624 were complete. More than 94% of the respondents start cytology testing at age 18 years. Almost three fourths (74.2%) continue screening indefinitely. More than 80% use a liquid-based method of collection. Almost two thirds (65.1%) order human papillomavirus testing occasionally, usually (81.9%) for reports of atypical squamous cells of undetermined significance (ASCUS). Most Fellows in the sample perform colposcopy for an ASCUS result. Reports of atypical glandular cells resulted in variable approaches to further evaluation. Patient age and history were important variables for all test reports. Legal concerns were mentioned as important determinants of practice patterns.

CONCLUSION

In this sample of ACOG Fellows, most perform cervical cytology and evaluate abnormal results in accord with guidelines in place before the recommended changes in screening and evaluation were published in 2003.

The centrality of the clinician in the evaluation of patients with abnormal cervical cytologic studies

The management of women with abnormal cervical cytologic studies requires in-depth knowledge of the patient and the disease, as well as the illness caused by their interaction. Only the clinician has access to these three parameters. Therefore, recommendations regarding patient care made by the cytology laboratory that appear on the cytology report are often inappropriate, may lead to mismanagement, and have the potential for disruption of the physician-patient relationship. Even suggestions based on guidelines that are evidence based often do not apply to a particular patient because such guidelines are most appropriate for only the "average" patient.

Risk of breast cancer in women exposed to diethylstilbestrol in utero: prelimiinary results (United States)

BACKGROUND

A synthetic estrogen, diethylstilbestrol (DES), was widely prescribed to pregnant women during the 1950s and 1960s but was later discovered to be associated with an increased risk of clear-cell carcinoma of the vagina and cervix in female offspring. DES has not been linked to other cancers in female offspring, but studies of other prenatal factors such as twin gestation and pre-eclampsia have indicated that in-utero estrogen levels may influence breast cancer risk. We evaluated the relation of in-utero DES exposure to the risk of adult breast cancer.

METHODS

A cohort of 4821 exposed women and 2095 unexposed women, most of whom were first identified in the mid-1970s, were followed by mailed questionnaires for an average of 19 years. Reported cancer outcomes were validated by medical record review. Breast cancer incidence in DES-exposed daughters was compared with cancer incidence in unexposed daughters with use of Poisson regression analysis, adjusting for year of birth, age at menarche, age at first birth, and number of births.

FINDINGS

The rate ratio for incidence of invasive breast cancer in exposed versus unexposed women was 1.4 (95% confidence interval (CI) = 0.7-2.6). DES exposure was not associated with an increased risk of breast cancer in women under 40 years, but among women aged 40 and older the rate ratio was 2.5 (95% CI = 1.0-6.3). The rate ratio for the association of DES exposure with estrogen receptor-positive tumors was 1.9 (95% CI = 0.8-4.5).

INTERPRETATION

While not statistically significant, the overall 40% excess risk, arising exclusively from the subset of estrogen receptor-positive cases, raises a concern calling for continued investigation.

The management of ASCUS cervical cytologic abnormalities and HPV testing: a cautionary note

A recently published study of the management of low-grade cytologic smears compared immediate colposcopy to human papillomavirus (HPV) triage and entry cytology smears (conservative management) as three triage techniques for managing atypical squamous cells of undetermined significance (ASCUS) smears (Atypical Squamous Cells of Undetermined Significance/Low-grade Squamous Intraepithelial Lesion Triage Study [ALTS]). The study reported a high sensitivity (96.3%) for HPV testing using hybrid capture 2 to detect cervical intraepithelial neoplasia (CIN) III. The authors concluded that HPV testing is a viable option for managing ASCUS smears. We have reviewed the published data from the ALTS trial and have found a large excess of colposcopies and biopsies in the HPV arm in comparison with the conservative management (cytology) arm. In addition, the ALTS trial quality control and pathology review results raise doubts about the diagnostic validity of the study to establish standards of clinical practice. Furthermore, until the 2-year follow-up analysis of the conservative management arm is completed to detect CIN III, a valid comparison between HPV triage and conservative management is not possible. We conclude that, based on published data, HPV testing for routine clinical management of low-grade cytologic abnormalities (ASCUS smears) is not warranted, and that HPV testing is currently an investigational tool.

Incidence of squamous neoplasia of the cervix and vagina in women exposed prenatally to diethylstilbestrol (United States)

OBJECTIVES

Women exposed prenatally to diethylstibestrol (DES) have an excess risk of clear-cell adenocarcinoma of the vagina and cervix, but the effect on the incidence of squamous neoplasia is uncertain. The purpose of the current study was to evaluate the long-term risk of developing high-grade squamous neoplasia of the genital tract among women exposed prenatally to DES.

METHODS

A cohort comprising 3,899 DES-exposed and 1,374 unexposed daughters was followed for 13 years (1982 1995) for pathology-confirmed diagnoses of high-grade squamous intraepithelial neoplasia (HSIL) of the genital tract. Poisson regression analysis was used to compute relative risks (RR) and 95% confidence intervals (95% CI), adjusting for age, calendar year, and other covariates.

RESULTS

The RR (95% CI) among DES-exposed versus unexposed, based on 111 cases of high-grade disease, was 2.1 (1.2-3.8). Adjustment for screening history estimated by the number of years since the last Pap smear had little effect. Risk estimates were higher with earlier intrauterine exposure; the RR (95% CI) for exposure within 7 weeks of the last menstrual period was 2.8 (1.4-5.5). Only two cases of invasive squamous cervical cancer occurred in total, precluding separate analysis.

CONCLUSIONS

The findings support an association between in-utero DES exposure and high-grade squamous neoplasia, although a role for more intensive screening among DES-exposed women in the production of this excess could not be completely ruled out.

Infertility among women exposed prenatally to diethylstilbestrol

Although it is well established that women exposed to diethylstilbestrol in utero have an increased risk of spontaneous abortion, ectopic pregnancy, and preterm delivery, it is not known whether they also have an increased risk of infertility. The authors assessed this question in data from a collaborative follow-up study of the offspring of women who took diethylstilbestrol during pregnancy. In 1994, 1,753 diethylstilbestrol-exposed and 1,050 unexposed women from an ongoing cohort study (National Cooperative Diethylstilbestrol Adenosis Study and Dieckmann cohorts) provided data on difficulties in conceiving and reasons for the difficulty. Age-adjusted relative risks were computed for the association of diethylstilbestrol exposure with specific types of infertility. A greater proportion of exposed than unexposed women were nulligravid (relative risk (RR) = 1.3, 95% confidence interval (CI): 1.1, 1.5), and a greater proportion had tried to become pregnant for at least 12 months without success (RR = 1.8, 95% CI: 1.6, 2.1). Diethylstilbestrol exposure was significantly associated with infertility due to uterine and tubal problems, with relative risks of 7.7 (95% CI: 2.3, 25) and 2.4 (95% CI: 1.2, 4.6), respectively. The present findings indicate that diethylstilbestrol-exposed women have a higher risk of infertility than do unexposed women and that the increased risk of infertility is primarily due to uterine or tubal problems.

Cancer risk in men exposed in utero to diethylstilbestrol

BACKGROUND

An association between prenatal diethylstilbestrol (DES) exposure and cancer in men, especially testicular cancer, has been suspected, but findings from case-control studies have been inconsistent. This study was conducted to investigate the association between prenatal DES exposure and cancer risk in men via prospective follow-up.

METHODS

A total of 3613 men whose prenatal DES exposure status was known were followed from 1978 through 1994. The overall and site-specific cancer incidence rates among the DES-exposed men were compared with those of the unexposed men in the study and with population-based rates. The relative rate (RR) was used to assess the strength of the association between prenatal DES exposure and cancer development. All statistical tests were two-sided.

RESULTS

Overall cancer rates among DES-exposed men were similar to those among unexposed men (RR = 1.07; 95% confidence interval [CI] = 0.58 to 1.96) and to national rates (RR = 0.99; 95% CI = 0.65 to 1.44). Testicular cancer may be elevated among DES-exposed men, since the RRs for testicular cancer were 3.05 (95% CI = 0.65 to 22.0) times those of unexposed men in the study and 2.04 (95% CI = 0.82 to 4.20) times those of males in the population-based rates. The higher rate of testicular cancer in the DES-exposed men is, however, also compatible with a chance observation.

CONCLUSIONS

To date, men exposed to DES in utero do not appear to have an increased risk of most cancers. It remains uncertain, however, whether prenatal DES exposure is associated with testicular cancer.

Cancer risk in women exposed to diethylstilbestrol in utero

CONTEXT

The association between in utero exposure to diethylstilbestrol (DES) and clear cell adenocarcinoma (CCA) of the vagina and cervix is well known, yet there has been no systematic study of DES-exposed daughters to determine whether they have an increased risk of other cancers. As many as 3 million women in the United States may have been exposed to DES in utero.

OBJECTIVE

To determine whether women exposed to DES in utero have a higher risk of cancer after an average of 16 years of follow-up.

DESIGN

A cohort study with mailed questionnaires and medical record review of reported cancer outcomes.

PARTICIPANTS

A cohort of 4536 DES-exposed daughters (of whom 81% responded) and 1544 unexposed daughters (of whom 79% responded) who were first identified in the mid-1970s.

MAIN OUTCOME MEASURES

Cancer incidence in DES-exposed daughters compared with population-based rates and compared with cancer incidence in unexposed daughters.

RESULTS

To date, DES-exposed daughters have not experienced an increased risk for all cancers (rate ratio, 0.96; 95% confidence interval [CI], 0.58-1.56) or for individual cancer sites, except for CCA. Three cases of vaginal CCA occurred among the exposed daughters, resulting in a standardized incidence ratio of 40.7 (95% CI, 13.1-126.2) in comparison with population-based incidence rates. The rate ratio for breast cancer was 1.18 (95% CI, 0.56-2.49); adjustment for known risk factors did not alter this result.

CONCLUSIONS

Thus far, DES-exposed daughters show no increased cancer risk, except for CCA. Nevertheless, because exposed daughters included in our study were, on average, only 38 years old at last follow-up, continued surveillance is warranted to determine whether any increases in cancer risk occur during the menopausal years.

Environmental endocrine modulators and human health: an assessment of the biological evidence

Recently, a great deal of attention and interest has been directed toward the hypothesis that exposure, particularly in utero exposure, to certain environmental chemicals might be capable of causing a spectrum of adverse effects as a result of endocrine modulation. In particular, the hypothesis has focused on the idea that certain organochlorine and other compounds acting as weak estrogens have the capability, either alone or in combination, to produce a variety of adverse effects, including breast, testicular and prostate cancer, adverse effects on male reproductive tract, endometriosis, fertility problems, alterations of sexual behavior, learning disability or delay, and adverse effects on immune and thyroid function. While hormones are potent modulators of biochemical and physiological function, the implication that exposure to environmental hormones (e.g., xenoestrogens) has this capability is uncertain. While it is reasonable to hypothesize that exposure to estrogen-like compounds, whatever their source, could adversely affect human health, biological plausibility alone is an insufficient basis for concluding that environmental endocrine modulators have adversely affected humans. Diethylstilbestrol (DES) is a potent, synthetic estrogen administered under a variety of dosing protocols to millions of women in the belief (now known to be mistaken) that it would prevent miscarriage. As a result of this use, substantial in utero exposure to large numbers of male and female offspring occurred. Numerous studies have been conducted on the health consequences of in utero DES exposure among the adult offspring of these women. There are also extensive animal data on the effects of DES and there is a high degree of concordance between effects observed in animals and humans. The extensive human data in DES-exposed cohorts provide a useful basis for assessing the biological plausibility that potential adverse effects might occur following in utero exposure to compounds identified as environmental estrogens. The effects observed in both animals and humans following in utero exposure to sufficient doses of DES are consistent with basic principles of dose response as well as the possibility of maternal dose levels below which potential non-cancer effects may not occur. Significant differences in estrogenic potency between DES and chemicals identified to date as environmental estrogens, as well as an even larger number of naturally occurring dietary phytoestrogens, must be taken into account when inferring potential effects from in utero exposure to any of these substances. The antiestrogenic properties of many of these same exogenous compounds might also diminish net estrogenic effects. Based on the extensive data on DES-exposed cohorts, it appears unlikely that in utero exposure to usual levels of environmental estrogenic substances, from whatever source, would be sufficient to produce many of the effects (i.e., endometriosis, adverse effects on the male reproductive tract, male and female fertility problems, alterations of sexual behavior, learning problems, immune system effects or thyroid effects) hypothesized as potentially resulting from exposure to chemicals identified to date as environmental estrogens.

Incident and demographic trends in cervical neoplasia

During the past several years, information has been published that suggests that preinvasive cervical neoplasia may be increasing in the United States. Part of the increase can be explained by changes in disease definition, in disease reporting, and in screening patterns. However, a small increase may have occurred in certain population subsets.

The effect of changes in atmospheric pressure on the occurrence of the spontaneous onset of labor in term pregnancies

OBJECTIVE

Our purpose was to determine whether there is a relationship between changes in atmospheric pressure and spontaneous onset of labor in term pregnancy.

STUDY DESIGN

All women admitted to Medical Center of Central Massachusetts-Memorial Hospital with spontaneous onset of labor at term and who were delivered on the service during a 12-month period represent the cohort for this study. Each maternal chart was abstracted to ensure that each member of the cohort met the inclusion criteria. Hourly recordings of atmospheric pressure made at the Worcester Station of the National Weather Service, Department of Commerce, were used as the meteorologic data points of interest. Least-squares regression was used to determine an equation that expresses the probability of the onset of labor in this cohort as a function of gestational age, which was used to calculate expected numbers for the statistical analyses. Two relationships were studied: (1) the ratio of the observed to the expected number of onsets of labor and (2) the initiation of labor and atmospheric pressure changes in the preceding 3 hours.

RESULTS

Three-hour periods of falling atmospheric pressure were less often followed by initiation of labor than were the periods with other types of pressure sequences. No association was observed between the onset of labor and days of low mean pressure.

CONCLUSION

Although there was an observed statistically significant association between falling barometric pressure and onset of labor, the magnitude of the difference is not of clinical significance.

Role of colposcopy in the examination of diethylstilbestrol-exposed women

Both epithelial and structural abnormalities of the lower genital tract are known to occur in women exposed in utero to DES with greater frequency than in the general population. These changes are usually easily identified by pelvic and colposcopic examination. In general, no treatment is suggested for benign changes. DES-exposed women, however, must be carefully followed-up because of the potential, although rare, of the development of clear cell adenocarcinoma and the increased incidence of squamous intraepithelial neoplasia. With rare exception, screening at yearly intervals is sufficient.

Increased risk of profound weight loss among women exposed to diethylstilbestrol in utero

We surveyed 1711 women exposed to diethylstilbestrol in utero, and 919 women not exposed, concerning lifetime weight loss histories. The prevalence of a history of unexplained profoundly low body weight (weight less than or equal to 80% of expected weight for age, sex, and height) was 18.7 per 1000 in the exposed group compared to 3.3 per 1000 in the unexposed group; a 5.72 to 1 ratio of increased risk.

Cervical cytology and the evaluation of the abnormal Papanicolaou smear

The pap smear is a safe, easy, and inexpensive method for the screening of large numbers of sexually active women for the presence of neoplasia of the cervix. When the pap smear is reported as being abnormal, it is highly accurate. Unfortunately, some cytology laboratories report lesions as "Class II" or "atypical." These reports are not helpful to the clinician and require further evaluation. Most sexually active women are at "high risk" for the development of cervical neoplasia because of early sexual activity for multiple sexual partners. All women at high risk should have annual pap smears. If a woman has a pap smear that suggests the presence of CIN (dysplasia or carcinoma in situ), colposcopy should be performed. This office procedure allows for the detection of the areas causing the abnormal cytology. Colposcopy can often allow outpatient therapy of CIN lesions. Conization should be performed only when the colposcopic examination is unsatisfactory or patient or lesion factors are not favorable for office therapy. Hysterectomy is not recommended for treatment of cervical dysplasia or carcinoma in situ.

Cancer after exposure to metronidazole

We assessed the risk of occurrence of cancer associated with exposure to metronidazole in the 771 female residents of Rochester, Minnesota, who were treated with metronidazole for vaginal trichomoniasis during the period 1960 through 1969 and were followed up for a total of 12,628 person-years. Standardized morbidity and mortality ratios were determined by using an expected number calculated by applying age-specific incidence rates from Rochester studies and Cancer Surveillance, Epidemiology, and End-Results Reporting (SEER) data to the person-years of follow-up. The overall standardized morbidity ratios for cancer at all sites were 1.4 (Rochester, 1978 through 1983), 1.5 (SEER data for Iowa, 1978 through 1981), and 1.2 (SEER data for Connecticut, 1978 through 1981). By site of the cancers, the standardized morbidity ratios greater than unity were those for malignant lesions of the lung, breast, thyroid, bladder, brain, kidney, nasopharynx, and oral cavity, as well as for multiple myeloma and malignant melanoma; however, the only significantly elevated standardized morbidity ratio was that for bronchogenic carcinoma. After adjustment for smoking status, the standardized morbidity ratio for bronchogenic cancer was 2.5 (95% confidence interval of 1.3 to 4.4). The standardized mortality ratio for cancer at all sites was 1.4 (95% confidence interval of 0.9 to 2.2). The analysis of these data suggests no significant increase in cancer-related morbidity or mortality for women exposed to metronidazole for treatment of vaginal trichomoniasis.