Maternal lipid levels during pregnancy and gestational diabetes: a systematic review and meta-analysis

BACKGROUND

Lipid levels during pregnancy in women with gestational diabetes mellitus (GDM) have been extensively studied; however, it remains unclear whether dyslipidaemia is a potential marker of preexisting insulin resistance.

OBJECTIVE

To evaluate the relationship between lipid measures throughout pregnancy and GDM.

SEARCH STRATEGY

We searched PubMed-MedLine and SCOPUS (inception until January 2014) and reference lists of relevant studies.

SELECTION CRITERIA

Publications describing original data with at least one raw lipid (total cholesterol, high-density lipoprotein cholesterol [HDL-C], low-density lipoprotein cholesterol [LDL-C], or triglyceride) measurement during pregnancy in women with GDM and healthy pregnant controls were retained.

DATA COLLECTION AND ANALYSIS

Data extracted from 60 studies were pooled and weighted mean difference (WMD) in lipid levels was calculated using random effects models. Meta-regression was also performed to identify sources of heterogeneity.

MAIN RESULTS

Triglyceride levels were significantly elevated in women with GDM compared with those without GDM (WMD 30.9, 95% confidence interval [95% CI] 25.4-36.4). This finding was consistent in the first, second and third trimesters of pregnancy. HDL-C levels were significantly lower in women with GDM compared with those without GDM in the second (WMD -4.6, 95% CI -6.2 to -3.1) and third (WMD -4.1, 95% CI -6.5 to -1.7) trimesters of pregnancy. There were no differences in aggregate total cholesterol or LDL-C levels between women with GDM and those without insulin resistance.

AUTHOR'S CONCLUSIONS

Our meta-analysis shows that triglycerides are significantly elevated among women with GDM compared with women without insulin resistance and this finding persists across all three trimesters of pregnancy.

Cervical surgery for cervical intraepithelial neoplasia and prolonged time to conception of a live birth: a case-control study

OBJECTIVE

To determine whether women with a history of surgery for cervical intraepithelial neoplasia (CIN) are at an increased risk of subfertility, measured as a time to pregnancy of more than 12 months.

DESIGN

Case-control study.

SETTING

Iowa Health in Pregnancy Study (IHIPS), a population-based case-control study of preterm and small-for-gestational-age (SGA) live birth outcomes (from May 2002 through June 2005) in the USA.

SAMPLE

Women with an intended pregnancy and a history of either one prior cervical surgery (n = 152), colposcopy only (n = 151), or no prior cervical surgery or colposcopy (n = 1021).

METHODS

Cervical treatment history, pregnancy intention, time to pregnancy, and other variables were self-reported by computer-assisted telephone interviews. Odds ratios were calculated using logistic regression to estimate the risk of prolonged time to pregnancy among women with a history of cervical surgery or colposcopy alone, compared with untreated women (control group).

MAIN OUTCOME MEASURE

Prolonged time to pregnancy (i.e. >1 year).

RESULTS

Prolonged time to pregnancy was most prevalent among treated women (16.4%), compared with untreated women (8.4%) and women with colposcopy only (8.6%) (P = 0.039). After adjusting for covariates, women with prior cervical surgery had a more than two-fold higher risk of prolonged time to pregnancy compared with untreated women (aOR 2.09, 95% CI 1.26-3.46). In contrast, women with a history of colposcopy only had a risk equivalent to that found among untreated women (aOR 1.02, 95% CI 0.56-1.89).

CONCLUSIONS

Women with a history of cervical treatment for CIN are at increased risk of subfertility, measured as a time to pregnancy of more than 12 months.

Association of human leucocyte antigen sharing with recurrent spontaneous abortions

An estimated 15% of clinically recognized pregnancies abort spontaneously. Recurrent spontaneous abortion (RSA) is defined as three or more consecutive miscarriages conceived with the same partner in the absence of uterine, genetic or autoimmune abnormalities. Evidence points to human leucocyte antigens (HLA) as playing a role in the successful development of the foetus. In particular, HLA compatibility is more prevalent in couples experiencing reproductive failure, especially RSA couples, compared to fertile couples. According to the immunological hypothesis, an adequate immune response is necessary for proper implantation of the embryo; conversely, a depressed response of maternal lymphocytes to the stimulation by paternal antigens because of HLA sharing can result in disorders, such as RSA. The genetic hypothesis implicates homozygosity for recessive lethal alleles in linkage disequilibrium with specific HLA haplotypes. The specificity of HLA alleles or haplotypes responsible for or linked to other RSA susceptibility genes remains unclear. In this study, we identified 40 observational studies (32 case-control, five cohort, one cross-sectional, one case series and one basic science) that examined the associations between HLA and RSA, focusing on HLA allele couple and maternal-foetal sharing, and the special role of HLA-G. We sought to identify consistent findings among studies examining similar questions. Evidence remains divided concerning the role of HLA allele couple sharing. Of major concern is the focus of many studies on couple sharing as a proxy measure of maternal-foetal sharing. Therefore, adequately powered studies are needed, which employ standard case definitions and reproducible methodologies to directly assess the role of maternal-foetal HLA sharing on the risk of RSA.

Work, leisure-time physical activity, and risk of preeclampsia and gestational hypertension

Few studies of preeclampsia have assessed physical activity level, yet recent evidence suggests that the pathologic mechanisms in preeclampsia are similar to those in cardiovascular disease, for which physical activity is shown to be protective. The authors assessed the independent and combined effects of work and regular leisure-time physical activity (LTPA) during early pregnancy on risk of de novo preeclampsia (n = 44) and gestational hypertension (n = 172) among women recruited from 13 obstetric practices in the New Haven, Connecticut, area between 1988 and 1991. Control subjects were normotensive throughout pregnancy (n = 2,422). Information on time at work spent sitting, standing, and walking and on LTPA before and during pregnancy was collected via face-to-face interviews. Logistic regression analyses suggested that women who engaged in any regular LTPA regardless of caloric expenditure (adjusted odds ratio (aOR) = 0.66, 95% confidence interval (CI): 0.35, 1.22), were unemployed (aOR = 0.64, 95% CI: 0.21, 2.00), or had nonsedentary jobs (aOR = 0.71, 95% CI: 0.37, 1.36) were at decreased risk of preeclampsia. Analyses of gestational hypertension showed no indication of a protective effect of workplace activity, LTPA, or unemployment. Consistent with other studies, these data suggest that regular physical activity during pregnancy may reduce preeclampsia risk.

Maternal caffeine intake and intrauterine growth retardation

This study estimates the effect of maternal caffeine consumption throughout pregnancy on fetal growth. We studied 2,714 women who delivered a liveborn infant between 1988 and 1991. Detailed information regarding coffee, tea, and soda drinking during the first and third trimesters of pregnancy was obtained. Average caffeine intake during month 1 of pregnancy was higher than for month 7 (72.4 vs 54.0 mg per day). Consumption of >300 mg caffeine per day during month 1 (adjusted odds ratio = 0.91; 95% confidence interval = 0.44--1.90) and during month 7 (adjusted odds ratio = 1.00; 95% confidence interval = 0.37--2.70) was not associated with intrauterine growth retardation. There was little evidence for any effect modification due to cigarette smoking on the caffeine associations. This study provides evidence that antenatal caffeine consumption has no adverse effect on fetal growth.

Racial disparity in pregnancy-related mortality associated with livebirth: can established risk factors explain it?

The authors conducted a nested case-control study to determine whether the fourfold increased risk of pregnancy-related mortality for US Black women compared with White women can be explained by racial differences in sociodemographic and reproductive factors. Cases were derived from a national surveillance database of pregnancy-related deaths and were restricted to White women (n = 840) and Black women (n = 448) whose pregnancies resulted in a livebirth and who died of a pregnancy-related cause between 1979 and 1986. Controls were derived from national natality data and were randomly selected White women and Black women who delivered live infants and did not die from a pregnancy-related cause (n = 5,437). Simultaneous adjustment for risk factors by using logistic regression did not explain the racial gap in pregnancy-related mortality. The largest racial disparity occurred among women with the lowest risk of pregnancy-related death: those of low to moderate parity who delivered normal-birth-weight babies (adjusted odds ratio = 3.53, 95% confidence interval: 2.9, 4.4). In contrast, no racial disparity was found among women with the highest risk of pregnancy-related death: high-parity women who delivered low-birth-weight babies. These findings indicate that reproductive health care professionals need to develop strategies to reduce pregnancy-related deaths among both high- and low-risk Black women.

Abortion and its effect on risk of preeclampsia and transient hypertension

We examined the effect of abortion type, number, and gestational age on the risk of preeclampsia and transient hypertension among women who received prenatal care from 13 obstetric practices in southern Connecticut between April 1988 and December 1991 (N = 2,739). Subjects were interviewed before 16 weeks' gestation regarding reproductive history and pregnancy-related risk factors. We estimated the risk of preeclampsia (N = 44) and transient hypertension (N = 172) among nulliparous women who had had one or more abortions, with nulliparous women with no abortion as the referent group. Similar effects were seen for one spontaneous or induced abortion, when analyzed separately. A single prior abortion was associated with a decreased risk of preeclampsia [odds ratio (OR) = 0.35; 95% exact confidence interval (CI) = 0.09-1.01]. One abortion had only a small association with risk of transient hypertension (OR = 1.09, 95% exact CI = 0.68-1.72); however, a history of two or more abortions was associated with a decreased risk (OR = 0.42, 95% exact CI = 0.16-0.94). Among nulliparous women with a history of one abortion, a decreased risk of both hypertensive disorders was observed among women whose aborted pregnancy ended at > or =3 months gestation. These findings suggest that a history of abortion in nulliparous women is a protective factor against the risk of preeclampsia in the subsequent pregnancy.

Maternal anthropometric factors and risk of primary cesarean delivery

OBJECTIVES

This study examined absolute and proportional gestational weight gain and prepregnancy body mass index as predictors of primary cesarean delivery.

METHODS

Data were derived from a prospective study of pregnancy outcome risk factors in 2301 women in greater New Haven, Conn, who had singleton deliveries by primary cesarean (n = 312) or vaginal delivery (n = 1989) and for whom height, prepregnancy weight, and weight gain were available. Women were divided into 4 body mass index groups (underweight, low average, high average, and obese) and further subdivided into 8 groups according to median proportional or absolute weight gain.

RESULTS

Risk of cesarean delivery increased with increasing body mass index and gestational weight gain greater than the median for one's body mass index. Proportional weight gain was more predictive of cesarean delivery than absolute weight gain. Underweight women gaining more than 27.8% of their prepregnancy weight had a 2-fold adjusted relative risk of cesarean delivery.

CONCLUSIONS

Proportional weight gain is an important predictor of cesarean delivery for underweight women; high body mass index is also predictive of increased risk.

Low-to-moderate gestational alcohol use and intrauterine growth retardation, low birthweight, and preterm delivery

PURPOSE

Heavy drinking during pregnancy is an established risk factor for fetal alcohol syndrome and other adverse perinatal outcomes. However, there is still debate as to the effects of low-to-moderate drinking during pregnancy.

METHODS

This prospective investigation was based on 2714 singleton live births at Yale-New Haven Hospital during 1988-1992. Alcohol drinking during pregnancy was evaluated with respect to intrauterine growth retardation (IUGR), preterm delivery, and low birthweight.

RESULTS

Mild drinking, defined as > 0.10-0.25 oz of absolute alcohol per day, during the first month of pregnancy was associated with a protective effect on IUGR (OR, 0.39; 95% confidence interval (CI), 0.20-0.76). Overall, drinking during month 1 of pregnancy suggested a curvilinear effect on growth retardation, with consumption of > 1.00 oz of absolute alcohol per day showing increased risk. Drinking during month 7 was associated with a uniform increase in the odds of preterm delivery; the ORs were 2.88 (95% CI, 1.64-5.05) for light drinking and 2.96 (95% CI, 1.32-6.67) for mild-to-moderate alcohol consumption.

CONCLUSIONS

Differences in the risk estimates for IUGR and preterm delivery may indicate etiological differences that warrant further investigation of these outcomes and critical periods of exposure. Low birthweight is not a useful neonatal outcome for this exposure because it is a heterogeneous mix of preterm delivery and IUGR. Despite the observed protective effects of mild drinking on IUGR, the increased risk of preterm delivery with alcohol use supports a policy of abstinence during pregnancy.

Head and neck radiation carcinogenesis: epidemiologic evidence

This article provides an overview of the long-term carcinogenic effects of medical radiation exposure to the head and neck and focuses on studies that allow risk quantification. The thyroid gland in children is extremely sensitive to the tumorigenic effects of external radiation for many years after exposure. Risk of thyroid cancer decreases with increasing age at exposure, with little risk, if any, apparent among persons exposed as adults. Large risks of neural tumors have been reported after moderate- and high-dose radiotherapy in childhood; however, the magnitude of the risk at low doses and for adult exposures is unclear. Data on salivary gland tumors are limited but tend to support an association with radiation exposure. In contrast, the pituitary gland appears to be relatively resistant to the tumorigenic effects of radiation. Several cohort studies have reported an increased risk of hyperparathyroidism among irradiated populations. In summary, radiation exposure to the head and neck can result in tumors of the thyroid, salivary, and parathyroid glands, as well as the brain and central nervous system.

Violence and women's health. The role of epidemiology

Survival, a basic indicator of health, indicates that violence is a threat to the health of women. Furthermore, the quality of women's lives is compromised by the threat of violence, which creates a sense of chronic endangerment. "Stranger danger" is a misplaced emphasis; community-based investigations in the past decade have underscored that women are at highest risk of homicide, physical assault, and sexual assault at the hands of a man they know, often their husband or male intimate. Potential contributions of the science of epidemiology are identified and the relative absence of epidemiologists working in the field is noted. Violence against women may be an important, although often ignored, confounding variable or effect modifier in studies of women's health.

Do alcohol intake and mammographic densities interact in regard to the risk of breast cancer?

BACKGROUND

The effect of alcohol intake on mammographic densities and the possible interaction between these two factors in regard to the risk of breast cancer were assessed using information from the Breast Cancer Detection and Demonstration Project.

METHODS

Mammograms taken during the first year of screening for patients whose breast cancer was detected in the 5th year of follow-up (n = 266) and their matched controls (n = 301) were blindly assessed for the percent of mammographic densities, which were measured by planimetry.

RESULTS

Among controls, alcohol intake was weakly, positively associated with the percent of mammographic densities (Spearman rank correlation coefficient, 0.09), although the association may have been the result of chance (P = 0.12). After adjustment for confounding factors, the lifetime alcohol intake did not appear to modify the effect of the percent mammographic densities on the risk of breast cancer (P for the interaction, 0.09).

CONCLUSIONS

Longitudinal studies and larger case-control studies should be conducted to assess the relationship between diet and changes in mammographic densities further.

Is breast size a predictor of breast cancer risk or the laterality of the tumor?

The relationship of breast size both to breast cancer risk and to the laterality of the tumor was studied among 261 women diagnosed with breast cancer and 291 control subjects who were enrolled in the United States' Breast Cancer Detection and Demonstration Project from 1973 to 1980. Standardized measures of breast area were obtained by applying planimetry to bilateral screening mammograms taken four years before breast cancer was diagnosed in case subjects. The left breast was larger in 53 percent of women with breast cancer and in 60 percent of women in the control group; the difference in breast area by laterality was significant only among controls (P = 0.01). To assess breast cancer risk, breast area was categorized by quartiles, with the lowest quartile being the referent group. Risk was increased minimally among women with the largest breast area (odds ratios = 0.9, 0.9, 1.2); however, the point estimates were not statistically significant and there was no evidence of a linear trend. Left-sided diseased was diagnosed in 51 percent of women in the case group. Although the mean area of the breast with the malignancy did not differ significantly from the opposite breast, cancer developed in the larger breast of 57 percent of women with left- and 46 percent of women with right-sided disease. Breast size was associated with cancer of the left breast but not the right. However, these size differences were small since the area of the larger breast was less than 10 percent greater than the smaller breast among half of the case subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Trends in obstetric operative procedures, 1980 to 1987

OBJECTIVES

Increasing rates of cesarean deliveries have received widespread attention in recent years, as concern in the United States about unnecessary surgical procedures has increased. However, little information has been published on the national trends of other operative obstetric procedures occurring during deliveries.

METHODS

We analyzed data from the National Hospital Discharge Survey to examine trends in the use of forceps, vacuum extraction, and cesarean section from 1980 through 1987.

RESULTS

The rate of cesarean sections increased by 48%, while the rate of forceps procedures declined by 43%. Although the risk of cesarean section was significantly increased for older women, the risk of forceps and vacuum extraction procedures did not vary by age. Women with private insurance were significantly more likely to receive a cesarean section (rate ratio [RR] = 1.2), forceps procedure (RR = 1.7), and vacuum extraction procedure (RR = 1.8) than were women without private insurance.

CONCLUSIONS

As pressure mounts to decrease the national cesarean section rate from 24% to 15% by the year 2000, attention should also be given to surveillance of other operative delivery procedures.

Hospitalization for pregnancy complications, United States, 1986 and 1987

OBJECTIVE

The purpose of our analysis was to provide a national overview of the magnitude of the public health burden associated with inpatient care for pregnancy complications.

STUDY DESIGN

We analyzed data from the National Hospital Discharge Survey for 1986 and 1987. We calculated ratios of hospitalizations for pregnancy complications for every 100 hospitalizations involving a birth. Standard errors for these ratios were calculated with RATIOEST, and relative ratios with 95% confidence intervals were calculated for subgroups of interest.

RESULTS

We found that for every 100 hospitalizations involving a birth, there were 22.2 nondelivery hospitalizations for pregnancy complications (14.6 antenatal complications, 7.6 pregnancy loss complications). These ratios were higher for black than for white women (relative ratio 1.4, 95% confidence interval 1.2 to 1.6). The effects of marital status, age, and insurance coverage differed between black and white women, and mean length of stay was longer for black than for white women.

CONCLUSION

Hospitalization for pregnancy complications is far more common than is widely appreciated and is more frequent among black than white women.

National trends in the incidence of abruptio placentae, 1979-1987

Premature separation of the normally implanted placenta is a serious complication of pregnancy and a leading cause of maternal and perinatal morbidity and mortality. Using data from the National Hospital Discharge Survey, we estimated rates of abruptio placentae in the United States for the years 1979-1987 and examined the association of this condition with several demographic risk factors and coexisting obstetric conditions. In 1987, the national rate was 11.5 cases per 1000 deliveries. The rate of abruptio placentae increased significantly between the years 1979-1987 among women of all racial groups. The increase in the rate of placental abruption occurred mainly among women under the age of 25, unmarried women, and women on Medicaid compared with those who had private insurance. Women with placental abruption were 54 times more likely to have coagulopathies and 11 times more likely to have stillbirths than those without placental abruption. Twin gestations, preterm premature rupture of membranes, chorioamnionitis, chronic hypertension, and preeclampsia/eclampsia were also associated with placental abruption. Although the cause for the increase in the incidence of abruptio placentae is not known, most of the increase occurred among women likely to be financially and socially disadvantaged.

National trends in the management of tubal pregnancy, 1970-1987

Tubal pregnancy leads to reduced childbearing potential and is a major cause of maternal morbidity and mortality in the United States. Several hospital-based studies have shown a trend toward more conservative management of tubal pregnancies, which reflects attempts to reduce morbidity and preserve fertility; however, the impact on future fertility remains unclear. To study national trends in the management of tubal pregnancy from 1970-1987, we analyzed data from the National Hospital Discharge Survey. Tubal pregnancies managed conservatively, using operative procedures that attempt to preserve the function of the involved fallopian tube, increased from approximately 2% in 1970-1978 to 12% in 1984-1987. During 1979-1987, conservative procedures were more than twice as common for women with private insurance as for those without it. The use of diagnostic laparoscopy increased from 10% of tubal pregnancies in 1970-1978 to 33% in 1979-1987, whereas the use of diagnostic laparotomy decreased from 24 to 2%.

Surveillance of postneonatal mortality, United States, 1980-1987

In the United States, one-third of all infant deaths (deaths of infants ages 0-364 days) occurs in the postneonatal period (28-364 days). A substantial proportion of these deaths potentially could be prevented. To examine recent trends in postneonatal mortality (PNM) in the United States, the investigators analyzed birth and death certificate data for resident infants for the period from 1980 through 1987. Rates of PNM declined 11% from 3.5 to 3.1/1,000 live births among white infants and declined 16% from 7.3 to 6.1/1,000 live births among black infants. Most of the decline resulted from reduced mortality from infectious diseases and injuries. A decreased mortality attributable to sudden infant death syndrome (SIDS) among black infants additionally accounted for the decline. Autopsy rates for SIDS increased from 82% to 92% but did not differ for black infants and white infants. Birth defects-related PNM declined more among white infants than among black infants. The racial gap in PNM (rate ratio (RR) = approximately 2.0) persisted. However, the largest black/white gap occurred in the Northeast (RR = 2.5), the region with the lowest PNM. Black infants were 2.7 and 2.3 times more likely to die of infections and injuries, respectively, than were white infants. Although PNM rates declined during the 1980s, a greater rate of reduction is needed to achieve the Year 2000 objectives, especially among black infants. Such reductions are possible through improved access to comprehensive pediatric care as well as education and community-oriented prevention programs designed to reduce deaths due to infections and injuries. A better understanding of the etiology of SIDS and birth defects is critical for preventing postneonatal deaths.

Mammographic densities and risk of breast cancer

To determine the relation of mammographic densities to subsequent breast cancer risk, a case-control study was undertaken using prediagnostic mammograms of screening program participants. Mammograms of cases (n = 266) and controls (n = 301) were blindly assessed for mammographic densities, which were measured by planimetry. The odds of breast cancer increased steadily with increasing breast density (test for trend, P less than 0.0001). Breast cancer odds was 1.7 for densities between 5% and 24.9%, 2.5 for 25% through 44.9%, 3.8 for 45% through 64%, and 4.3 for densities of 65% and greater (referent = less than 5% densities). Odds ratios also increased with increasing densities among women with the P2 and DY mammographic patterns. These findings suggest that the percentage of mammographic densities in the breast can predict breast cancer risk more accurately than a qualitative assessment of mammographic patterns.

Ectopic pregnancy surveillance, United States, 1970-1987

In 1987, both the rate of hospitalizations due to ectopic pregnancy and the number of women hospitalized increased from those reported in 1986. Although ectopic pregnancy represented 1.7% of all pregnancies in 1987, complications of this condition accounted for 12% of all maternal deaths in that year. The case-fatality rate was 3.4 deaths per 10,000 ectopic pregnancies, a decline of 30% from the rate of 4.9 deaths reported in 1986, and a 90% decline from the 35.5 deaths per 10,000 ectopic pregnancies reported in 1970. Although the racial gap decreased slightly in 1987, the risk of ectopic pregnancy remained 1.4 times higher for women of black and other minority races than for white women. The risk of death from this condition remained 1.8 times higher for women of black and other minority races.

Epidemiology of preeclampsia and eclampsia in the United States, 1979-1986

Preeclampsia and eclampsia continue to be among the leading causes of maternal death. However, national estimates of the occurrence of these conditions have not been available. To derive national rates of preeclampsia and eclampsia and to characterize the women at highest risk of the development of these conditions, we analyzed data from the National Hospital Discharge Survey for the years 1979 through 1986. We found that 26 per 1000 births during this period were complicated by preeclampsia and 0.56 per 1000 births were complicated by eclampsia. The rate of mild or unspecified preeclampsia remained constant over the study period. In contrast, the rate of severe preeclampsia increased sharply and the rate of eclampsia declined by 36%. Maternal age less than 20 years old was the strongest risk factor for both preeclampsia and eclampsia. These data indicate a need for improved prenatal care among teenagers.

Abortion surveillance, United States, 1984-1985

Since 1983, the number of legal abortions reported to CDC increased by 5% to 1,333,521 in 1984; in 1985, that number decreased by less than 1% to 1,328,570. The national abortion rate was the same for both years-24 per 1,000 females ages 15-44 years. The abortion ratio for 1984 was 364 legally induced abortions per 1,000 live births; the ratio for 1985 was 354 per 1,000. Abortion ratios were higher among women of black and other minority races and among women younger than 15 years of age. Women undergoing legally induced abortions tended 1) to be young, white, and unmarried, 2) to have had no previous live births, and 3) to be having the procedure for the first time. Curettage was the procedure used in 96% of the reported cases. Eleven deaths were associated with legally induced abortions in 1984, and six in 1985. The case-fatality rate in 1985 was 0.5 deaths per 100,000 legally induced abortions, down from the 0.8 per 100,000 reported in 1983 and 1984. Overall, since 1980, the numbers and rates of abortion have had only slight year-to-year fluctuations. The steady increase in the percentage of repeat abortions since 1972 reflects the ongoing availability of legal abortions. Since the beginning of CDC's abortion mortality surveillance, the number of deaths related to legal abortions has decreased 75%, from 24 deaths in 1972 to six deaths in 1985.

Ectopic pregnancy in the United States, 1970-1986

In 1986, both the rate of hospitalizations due to ectopic pregnancy and the number of hospitalizations decreased from those reported in the previous year, although the decreases were not statistically significant. If this leveling off of previous yearly increases becomes a continuing trend, possible explanatory hypotheses include a leveling off of disease occurrence, and an increasing use of outpatient management. The case-fatality rate rose slightly in 1986, to 4.9 deaths per 10,000 ectopic pregnancies, although this rate still represents an 86% decline from the 35.5 deaths per 10,000 ectopic pregnancies reported in 1970. In 1986, ectopic pregnancy accounted for only 1.4% of all pregnancies but was associated with over 13% of maternal deaths. Compared with white women, women of black and other minority races had a 1.6 times greater risk of ectopic pregnancy. Ectopic pregnancy remains one of the leading causes of maternal death in the United States and continues to be an important public health problem.

Mammographic parenchymal patterns as indicators of breast cancer risk

Mammographic parenchymal patterns have been suggested as indicators of breast cancer risk. However, few well-controlled studies have used prediagnostic mammograms to determine the pattern classification. The authors studied 266 cases of breast cancer and 301 controls from 25 screening centers of the Breast Cancer Detection and Demonstration Project, a nationwide screening program conducted between 1973 and 1980 to evaluate the risk associated with mammographic patterns using mammograms taken four years before the detection of breast cancer. Mammograms of the cancerous breast of cases and of the ipsilateral breast in the control matched to each case were blindly assessed by one of the investigators (J.N.W.), originator of the mammographic pattern classification. The breast cancer odds ratio among women with the combined P2 + DY patterns, compared with women with the N1 pattern, was 2.8 (95% confidence interval (CI): 1.6-5.1). This estimate of relative risk was comparable with the risk associated with other recognized breast cancer risk factors. The odds ratio among P2 + DY women with a first-degree family history of breast cancer was 5.5 (95% CI: 2.6-11.8) compared with N1 women without a family history. These data provide additional evidence that mammographic patterns are indicators for subsequent development of breast cancer, particularly among women with a first-degree family history of this malignancy.

Ectopic pregnancy surveillance, United States, 1970-1985

Ectopic pregnancy is now one of the leading causes of maternal death in the United States. In 1984 and 1985, both the numbers and rates of ectopic pregnancy increased. Since the rate of ectopic pregnancy remained unchanged for white women, the rate increase appears to be driven by the increasing rate among women of black and other races. Although ectopic pregnancies accounted for only 1.5% of the total pregnancies in 1984 and 1985, they accounted for 14% of the total maternal deaths in 1984 and for 11% of those deaths in 1985. However, the case-fatality rate for 1985 decreased to 4.2/10,000 ectopic pregnancies, down from the 35.5 deaths/10,000 ectopic pregnancies reported in 1970. Several factors may contribute to the increase in ectopic pregnancies, including heightened awareness of the condition, improved diagnostic technology, and possibly the higher prevalence of risk factors (e.g., acute and chronic salpingitis and sexually transmitted diseases) and the lower prevalence of protective factors (e.g., decreased use of oral contraceptives). Heightened awareness of the condition and improved technology may also be factors resulting in the decreased case-fatality rate.

Mammographic parenchymal patterns and quantitative evaluation of mammographic densities: a case-control study

The classification of breast parenchymal patterns (N1, P1, P2, DY) and the percentage of the breast containing radiographic densities are two highly correlated radiographic measures proposed as predictors of the risk of breast cancer. In this case-control study, 160 cases of breast cancer and 160 matched controls from a mammography referral practice were compared to determine the risk of breast cancer associated with each of these two radiographic measures. The mammographic densities were quantified on caudal projections by means of a compensating polar planimeter. A relative risk estimate of 3.3 (p less than .05) was associated with the P2 + DY patterns compared with the N1 + P1 patterns. Significantly elevated risks of 4.3 to 5.5 also were observed among women whose breasts contained at least 25% mammographic densities, compared with women with less than 25% involvement. These radiographic measures tended to be more predictive of the risk of breast cancer in black women than in white women. Although the precise clinical roles of breast parenchymal patterns and densities have not been defined fully, the results of this study suggest that they are useful in the recognition of women at high risk of breast cancer. We make no claims that the findings of this study are sufficiently developed to be used as a basis for screening strategies.

Cancer and other causes of death among Wisconsin farmers

Computerized mortality listings for Wisconsin for 1968-1976 were used in proportional mortality ratio (PMR) and proportional cancer mortality ratio (PCMR) analyses to evaluate mortality patterns among Wisconsin farmers. Examination of PCMR trends by per capita county level of agricultural production was limited to the youngest birth cohort (1905-1958) and cancer sites associated with farming exposures in either the present or previous analyses. Among all Wisconsin farmers, significantly decreased PMRs were seen for tobacco- and alcohol-related causes of death, while excesses occurred for accidental causes, asthma, and cancer of the stomach, prostate, eye, and lymphatic and hematopoietic systems. Elevated PCMR's for leukemia and all lymphopoietic cancer and cancers of the stomach, rectum, eye occurred in farmers born 1905-1958, while deficits were observed for cancer of the pancreas and the category, "all other cancers." Increases in PCMR's with level of various agricultural activities were largely associated with cancers of other lymphatic tissue (2/3 of which were multiple myeloma) and the rectum. Certain agricultural exposures were also positively associated with deaths due to cancers of the prostate, brain, lymphosarcoma and reticulosarcoma, and all lymphopoietic cancers. No positive PCMR gradients were observed for leukemia and malignancies of the stomach and eye. Modern chemical practices in farming may account for some of the patterns noted.

Methods of cancer case selection: implications for research

The race, age, and sex differences between clinically and microscopically diagnosed cancer cases for a total of 63,301 incident cases for 18 sites are reported. The cases, diagnosed during 1973-1978, were drawn from the Cancer Surveillance Section in the Division of Epidemiology at the Michigan Cancer Foundation in Detroit, a participant in the Surveillance, Epidemiology, and End Results (SEER) program. Although microscopically diagnosed cases and those diagnosed by other methods differed by race and sex for a few sites, the two case groups differed by age for 15 of the 18 sites examined. Cases without microscopic diagnoses (i.e., clinical diagnoses) tended to be older than microscopically confirmed cases. These findings indicate that in studies of certain cancer sites, the method of case selection could affect results pertaining to age differences in exposure to and effects of relevant risk factors.