Tap or bottled water consumption and spontaneous abortion: a 1986 case-control study in California.

To investigate whether drinking tap or bottled water during pregnancy affects the risk of spontaneous abortion, we asked questions about water consumption in a large case-control study (626 cases, 1,300 controls). The study ascertained cases from hospital pathology laboratory reports of pregnancies that began in 1986 and obtained controls from birth certificates. The crude odds ratio for consumption of any vs no cold tapwater at home during the first trimester was 1.2 (95% confidence interval = 1.0-1.5), with no dose-response effect. The crude odds ratio for any bottled water consumption was 0.79 (95% confidence interval = 0.65-0.96), with a downward trend by amount consumed. Adjusting for many potential confounders did not alter these associations appreciably, although some variables appeared to be effect modifiers. The point estimates were stronger among women who were more difficult to contact, suggesting the possibility of bias.     

Adverse pregnancy outcomes in relation to water consumption: a re-analysis of data from the original Santa Clara County Study, California, 1980-1981.

Residents of a census tract that received drinking water from a well contaminated with solvents were previously shown to experience a spontaneous abortion rate over twice that occurring in an unexposed census tract. In addition, the rate of birth defects in the exposed tract was three times that in the unexposed tract. Surprisingly, increased tapwater consumption was associated with higher rates of spontaneous abortions in both the exposed and the unexposed tracts. Subsequent studies in this area have investigated the relation between spontaneous abortions and consumption of tapwater in more detail. In this report, data from the original study have been re-analyzed using methods comparable with those used in more recent studies. These results confirm the association between spontaneous abortions and reported cold tapwater consumption that was seen in the original study. The observed effect was not due to maternal risk factors, nor was it a function of consumption of bottled water. After controlling for bottled water, the odds ratio for consumption of tapwater was 3.4 (95% confidence interval = 0.6-19.4).     

Tap or bottled water consumption and spontaneous abortion in a case-control study of reporting consistency.

A recent case-control study of 1,926 women found a slightly increased risk of spontaneous abortion associated with reported consumption of tapwater and a decreased risk with reported consumption of bottled water. In a case-control study of spontaneous abortion designed to examine the consistency of prenatal exposure reporting, the association of spontaneous abortion with tap or bottled water consumption was also examined. Cases of spontaneous abortion (N = 100) were ascertained from hospital pathology reports, and pregnant controls (N = 200) were obtained from obstetrical appointment logs. Subjects were first interviewed approximately 24 weeks after their last menstrual period and again approximately 48 weeks after their last menstrual period. Neither an increased risk for spontaneous abortion associated with consumption of tapwater nor a protective effect for consumption of bottled water was observed. Changes in reporting of tapwater consumption from the first to the second interview suggest the possibility of differential reporting in cases and controls. There was no evidence suggesting biased reporting of bottled water consumption.     

Spontaneous abortion and work with visual display units.

OBJECTIVE--To determine whether women who work with visual display units are at increased risk of spontaneous abortion. DESIGN--Case-control study. SETTING--Women were recruited during the three years 1987-9 from the Royal Berkshire Hospital in Reading, and from a large group practice situated within the hospital's catchment area. SUBJECTS--Cases were 150 nulliparous working women with a clinically diagnosed spontaneous abortion and controls were 297 nulliparous working women attending for antenatal care. MAIN OUTCOME MEASURES--Cases and controls were contacted and personally interviewed using the same structured questionnaire. Exposure to visual display units (VDUs) at work was assessed from information supplied at interview. RESULTS--No evidence of an increased risk of spontaneous abortion was found in women who reported that they used a VDU at work compared with women who reported that they did not (odds ratio (OR) = 0.9, 95% confidence interval (95% CI) = 0.6-1.4); and no relation with the amount of time spent actively using a VDU was evident (OR = 0.9, 95% CI = 0.5-1.6 for women who worked with a VDU for 21 hours or more each week). No effect of passive exposure to VDUs at work was found (OR = 0.9, 95% CI = 0.6-1.6 for women who reported working less than 10 feet away from a VDU that was usually switched on). These findings were not explained by maternal age, marital state, housing tenure, partner's social class, educational level, smoking, alcohol consumption, or number of previous spontaneous abortions. CONCLUSION--Given the findings and their consistency with the results from other recent studies it is concluded that pregnant women who work with VDUs are not at increased risk of clinically diagnosed spontaneous abortion. For the many women who use VDUs in their jobs, this finding provides reassurance.     

Spontaneous abortion and work with visual display units.

OBJECTIVE--To determine whether women who work with visual display units are at increased risk of spontaneous abortion. DESIGN--Case-control study. SETTING--Women were recruited during the three years 1987-9 from the Royal Berkshire Hospital in Reading, and from a large group practice situated within the hospital's catchment area. SUBJECTS--Cases were 150 nulliparous working women with a clinically diagnosed spontaneous abortion and controls were 297 nulliparous working women attending for antenatal care. MAIN OUTCOME MEASURES--Cases and controls were contacted and personally interviewed using the same structured questionnaire. Exposure to visual display units (VDUs) at work was assessed from information supplied at interview. RESULTS--No evidence of an increased risk of spontaneous abortion was found in women who reported that they used a VDU at work compared with women who reported that they did not (odds ratio (OR) = 0.9, 95% confidence interval (95% CI) = 0.6-1.4); and no relation with the amount of time spent actively using a VDU was evident (OR = 0.9, 95% CI = 0.5-1.6 for women who worked with a VDU for 21 hours or more each week). No effect of passive exposure to VDUs at work was found (OR = 0.9, 95% CI = 0.6-1.6 for women who reported working less than 10 feet away from a VDU that was usually switched on). These findings were not explained by maternal age, marital state, housing tenure, partner's social class, educational level, smoking, alcohol consumption, or number of previous spontaneous abortions. CONCLUSION--Given the findings and their consistency with the results from other recent studies it is concluded that pregnant women who work with VDUs are not at increased risk of clinically diagnosed spontaneous abortion. For the many women who use VDUs in their jobs, this finding provides reassurance.     

Pregnancy outcomes, infant mortality, and arsenic in drinking water in West Bengal, India

Between 2001 and 2003, the authors studied pregnancy outcomes and infant mortality among 202 married women in West Bengal, India. Reproductive histories were ascertained using structured interviews. Arsenic exposure during each pregnancy, including all water sources used, was assessed; this involved measurements from 409 wells. Odds ratios for spontaneous abortion, stillbirth, neonatal mortality, and infant mortality were estimated with logistic regression based on the method of generalized estimating equations. Exposure to high concentrations of arsenic (> or =200 microg/liter) during pregnancy was associated with a sixfold increased risk of stillbirth after adjustment for potential confounders (odds ratio (OR) = 6.07, 95% confidence interval (CI): 1.54, 24.0; p = 0.01). Arsenic-related skin lesions were found in 12 women who had a substantially increased risk of stillbirth (OR = 13.1, 95% CI: 3.17, 54.0; p = 0.002). The odds ratio for neonatal death was 2.81 (95% CI: 0.73, 10.8). No association was found between arsenic exposure and spontaneous abortion (OR = 1.01, 95% CI: 0.38, 2.70) or overall infant mortality (OR = 1.33, 95% CI: 0.43, 4.04). This study adds to the limited evidence that exposure to high concentrations of arsenic during pregnancy increases the risk of stillbirth. However, there was no indication of the increased rates of spontaneous abortion and overall infant mortality that have been reported in some studies.     

Caffeine consumption during pregnancy and spontaneous abortion

We conducted a case-control study of spontaneous abortion in Santa Clara County, California between 1986 and 1987. We analyzed data on 607 cases and 1,284 controls to evaluate the potential association between caffeine consumption during the first trimester of pregnancy and spontaneous abortion. About 70% of the women consumed caffeinated coffee, tea, and/or soda; 7% of the women consumed more than an average of 300 mg of caffeine daily. The crude odds ratio (OR) for heavy caffeine consumption (greater than 300 mg/day) was 1.55 (95% CI: 1.04-2.31), which decreased to 1.22 (95% CI: 0.80-1.87) after controlling for confounding factors. For these heavy users, nausea modified the association of spontaneous abortion and caffeine; heavy caffeine consumers reporting nausea had a doubled risk for spontaneous abortion (adjusted OR = 2.10, 95% CI: 1.20-3.70), in contrast to those who did not report nausea (adjusted OR = 0.53, 95% CI: 0.27-1.04). Heavy caffeine consumers who decreased their caffeine intake early in pregnancy had a risk of spontaneous abortion similar to that of nonconsumers.     

Prior spontaneous abortion, prior elective termination, interpregnancy interval, and risk of neural tube defects

A woman with a history of spontaneous abortion in her immediately prior pregnancy may be at increased risk for a pregnancy affected by a neural tube defect (NTD). A short interpregnancy interval may further increase this risk. Using data from a population-based case-control study (1989-1991), the authors investigated NTD risk resulting from a prior spontaneous abortion or elective termination and a short interpregnancy interval. Of 538 interviewed case mothers and 539 interviewed control mothers, 408 case mothers and 433 control mothers reported having a prior pregnancy. Analysis showed a slightly decreased NTD risk among mothers whose immediately prior pregnancy had ended in a spontaneous abortion or elective termination in comparison with a live birth (odds ratio (OR) = 0.82; 95% confidence interval (CI): 0.61, 1.1). This decreased risk was consistent across strata of short or long interpregnancy intervals. Additional analysis revealed an increased NTD risk for mothers with an interpregnancy interval of < or =6 months compared with >12-< or =24 months (OR = 1.5; 95% CI: 0.93, 2.4). This latter risk was greatest among mothers whose immediately prior pregnancy had resulted in a live birth (OR = 2.0; 95% CI: 1.0, 3.8) rather than a spontaneous abortion or elective termination (OR = 0.96; 95% CI: 0.44, 2.1). Adjustment for potential covariates did not substantially alter observed risk estimates.     

Social differences of very preterm birth in Europe: interaction with obstetric history. Europop Group.

Social differences of very preterm birth (22-32 completed weeks of amenorrhea) were studied using data from a large case-control survey in Europe between 1994 and 1997; 1,675 very preterm births and 7,965 full-term births were included. The relation between social factors and very preterm birth was studied according to obstetric history and the mode of delivery onset. Very preterm birth was significantly related to low educational level among women with no previous adverse pregnancy outcome (odds ratio (OR) = 2.67, 95 percent confidence interval (CI) 1.66-4.28) and among primigravid women and those with previous first-trimester abortion (OR = 2.01, 95 percent CI 1.56-2.58). In this group, unemployment of all household members was associated with a double risk of very preterm birth. No significant association between very preterm birth and socioeconomic status was observed among women with previous second-trimester abortion or preterm birth. Socioeconomic indicators remained significantly associated with both spontaneous and induced very preterm births among women with no previous late fetal loss or preterm birth. The results are consistent with social factors affecting the risk of very preterm birth, but the relation differs according to obstetric history.     

The use of electric bed heaters and the risk of clinically recognized spontaneous abortion

We conducted a prospective cohort study to evaluate the relation of spontaneous abortion and electric bed heater use during the first trimester of pregnancy. Compared with non-users, rates of spontaneous abortion were lower for women who used electric bed heaters. The adjusted odds ratio and 95% confidence interval (CI) for the two major devices used, electric blankets (N = 524) and waterbeds (N = 796), were, respectively, 0.8 (95% CI = 0.5-1.1) and 0.9 (95% CI = 0.7-1.2). An increase of risk with increasing intensity (setting-duration combination) of use was not observed. Users of electric blankets at low settings for most of the night (N = 171) had lower risks of spontaneous abortion than non-users (adjusted odds ratio = 0.5; 95% CI = 0.3-1.0). Twenty women who used electric blankets at a high setting for 1 hour or less had an adjusted odds ratio of 3.0 (95% CI = 1.1-8.3), but we found no spontaneous abortions among the few women (N = 13) who used a high setting for 2 or more hours. We found that exposure rankings of the magnetic field time-weighted average and a rate of change metric did not correspond monotonically to the pattern of spontaneous abortion risks and that electric blankets contribute less to overnight time-weighted average magnetic fields than has been thought.     

Induced abortion and low birthweight in the following pregnancy

BACKGROUND: To examine whether induced abortion increases the risk of low birthweight in subsequent singleton live births. METHODS: Cohort study using the Danish Medical Birth Registry (MBR), the Hospital Discharge Registry (HDR), and the Induced Abortion Registry (IAR). All women who had their first pregnancy during 1980-1982 were identified in the MBR, the HDR, and the IAR. We included all 15,727 women whose pregnancy was terminated by a first trimester induced abortion in the induced abortion cohort and 46,026 women whose pregnancy was not terminated by an induced abortion were selected for the control cohort. All subsequent pregnancies until 1994 were identified by register record linkage. RESULTS: Low birthweight (<2500 g) in singleton term live births occurred more frequently in women with one, two, three or more previous induced abortions, compared with women without any previous induced abortion of similar gravidity, 2.2% versus 1.5%, 2.4% versus 1.7%, and 1.8% versus 1.6%, respectively. Adjusting for maternal age and residence at time of pregnancy, interpregnancy interval, gender of newborn, number of previous spontaneous abortions and number of previous low birthweight infants (control cohort only), the odds ratios (OR) of low birthweight in singleton term live births in women with one, two or more previous first trimester induced abortions were 1.9 (95% CI: 1.6, 2.3), and 1.9 (95% CI: 1.3, 2.7), respectively, compared with the control cohort of similar gravidity. High risks were mainly seen in women with an interpregnancy interval of more than 6 months. CONCLUSIONS: The findings suggest a positive association between one or more first trimester induced abortions and the risk of low birthweight in subsequent singleton term live births when the interpregnancy interval is longer than 6 months. This result was unexpected and confounding cannot be ruled out.     

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.     

Induced abortion and risk of subsequent miscarriage

BACKGROUND: To evaluate the impact of surgically induced first-trimester abortion on the risk of miscarriage in a subsequent pregnancy. METHODS: The study is a pregnancy cohort study. It was conducted among 15 general hospitals or maternity and infant health institutes in Shanghai, China from November 1993 to March 1998. The abortion cohort consisted of pregnant women whose previous pregnancies were terminated by vacuum aspiration (98%). The reference cohort consisted of primigravidae. Subjects were recruited at 35-63 days of gestational age. A total of 2953 pregnant women were enrolled; 1502 in the abortion cohort, 1451 in the reference cohort. RESULTS: There were only 62 women lost to follow-up. The remaining 2891 women had 2732 live births, and 137 miscarriages. About 5.5% of pregnancies in the abortion cohort were miscarried and 4.0% in the reference cohort. Once potential confounders were controlled for by logistic regression, odds ratio (OR) of miscarriage between the abortion cohort and the reference cohort was 1.55 (95% CI: 1.08-2.23). The adjusted OR were 2.44 (95% CI: 1.16-5.15) among women who were recruited within 49 days of gestational age, and 1.72 (95% CI: 1.09-2.72) for the first-trimester miscarriage. CONCLUSIONS: Induced abortion by vacuum aspiration is associated with an increased risk of first-trimester miscarriage in the subsequent pregnancy.     

Human papillomavirus type 18/16 infection and prevalence among middle-aged and older Chinese rural women: a cross-sectional survey in Wufeng,Hubei Province

This study aimed to measure the prevalence and potential factors related to HPV 16/18 infection among middle-aged and older Chinese rural women. The study was conducted among women aged 35–65 years in rural villages within Wufeng in Hubei Province. Data were collected using a pretested questionnaire between July and August 2015. Cervical specimens were collected for HPV DNA detection and typing by using careHPV. Pearson’s Chi-square and logistic regression analyses were used to examine associations with HPV positivity. Among 1001 participants, the prevalence of HPV 18/16 positive genotyping was 15.88% (n = 159). Husbands’ extramarital sex (adjusted odds ratio [OR] = 15.85, 95% confidence interval [CI] 5.76–43.59), cervicitis (adjusted OR = 9.27, 95% CI 5.06–16.99), condom usage (adjusted OR = 0.16, 95% CI 0.05–0.53), higher average number of live births (adjusted OR = 1.98, 95% CI 1.32–2.96 for two live births; adjusted OR = 3.29, 95% CI 1.39–7.81 for three or more live births) were associated with HPV infection. The prevalence of HPV infection among participating women from rural areas was higher than that in several other areas in China. Our findings can aid efforts to prevent HPV infection to lower the risk of cervical cancer.     

Infertility and breast cancer: a population-based case-control study

To investigate whether a history of infertility affects a woman's risk of developing breast cancer, the authors analyzed case-control data collected between 1980 and 1982 as part of the Cancer and Steroid Hormone Study. The 4,730 cases were women aged 20-54 years with a first diagnosis of breast cancer ascertained from eight population-based cancer registries; the 4,688 controls were women randomly selected from the general population of these same eight areas. After controlling for age, age at first birth, and parity, the odds ratio (OR) for breast cancer associated with infertility was 1.01 (95% confidence interval (CI) 0.89-1.15) among gravid women. Controlling for age, the odds ratio was 0.82 (95% CI 0.59-1.14) among nulligravid women. Women who reported that the reason for their infertility was a problem with their ovaries had a risk similar to that for women without a history of infertility (OR = 0.75, 95% CI 0.48-1.24). Women whose physicians reported that the reason for their infertility was anovulation or Stein-Leventhal syndrome also had risks similar to those for women without a history of infertility (OR = 1.26 (95% CI 0.67-2.34) and OR = 1.13 (95% CI 0.46-2.78), respectively). Menopausal status, age at menarche, history of spontaneous abortions, drinking or smoking behavior, use of exogenous hormones, or family history of breast cancer did not appreciably alter the observed odds ratios. If infertility has an effect on breast cancer that is independent of age at first birth, then the effect is small.     

Subfertility and risk of spontaneous abortion

OBJECTIVES: The purpose of this study was to assess the association between subfertility and spontaneous abortion. METHODS: A total of 1572 women in New York and Vermont reported 3269 pregnancies between 1980 and 1990 and were able to provide an estimate of the waiting time to conception for 2967. Subfertility was defined as a delay of 1 year or more before a recognized conception was achieved. Rates of spontaneous abortion were determined among women with and without subfertility, and adjusted odds ratios (ORs) and 95% confidence intervals (CIs) were estimated via multiple logistic regression. RESULTS: Spontaneous abortion rates were 23.0% in pregnancies preceded by subfertility and 14.0% in pregnancies without impaired fertility (adjusted OR = 1.71, 95% CI = 1.26, 2.94). The attributable risk of spontaneous abortion associated with subfertility was 6.2%. CONCLUSIONS: Subfertile women evidence an increased number of spontaneous abortions.     

Relations of gestational length and timing and type of incomplete pregnancy to ovarian cancer risk

While the protective nature of parity with respect to ovarian cancer has been well documented, whether a history of incomplete pregnancy affects ovarian cancer risk is uncertain. Data collected from 739 epithelial ovarian cancer cases and 1,313 community controls in the Delaware Valley from 1994 to 1998 were used to evaluate the relation between gestational length and timing of first induced or spontaneous abortion and ovarian cancer risk. Incomplete pregnancy was not associated with ovarian cancer among nulliparous women or among ever-pregnant women either before or after adjustment for relevant confounders (for nulliparous women, odds ratio (OR) = 1.12, 95% confidence interval (CI): 0.66, 1.89; for ever-pregnant women, OR = 0.95, 95% CI: 0.76, 1.18). Among unigravid women, one full-term pregnancy was more protective than an incomplete pregnancy (adjusted OR = 0.29, 95% CI: 0.15, 0.57). These results were independent of the type of pregnancy loss. Among ever-pregnant women, a spontaneous abortion before a first birth provided significant protection (adjusted OR = 0.47, 95% CI: 0.30, 0.75), while no significant effect was found for an induced abortion prior to a first birth (adjusted OR = 0.80, 95% CI: 0.44, 1.47). These data do not support an independent association between incomplete pregnancies, either spontaneous or induced, and ovarian cancer risk.     

The relation between multiple births and maternal risk of breast cancer.

Data from two case-control studies conducted in New York State during 1982-1986 were used to examine the relation between multiple births and the maternal risk of breast cancer. The cases were 2,561 women between 20 and 79 years of age with a diagnosis of primary breast cancer. Controls (n = 2,616) were selected from driver's license files and matched to cases by year of birth and county of residence. The odds ratio for any multiple birth was 0.94 (95% confidence interval (CI) 0.56-1.56) in women less than 55 years of age and 0.95 (95% CI 0.62-1.46) in women aged 55-79 years. A previous study had shown a multiple last birth to be protective against breast cancer in women less than 55 years of age (odds ratio (OR) = 0.60, 95% CI 0.43-0.85). A decreased risk of breast cancer was also observed for this age group in the present study, but the magnitude of the effect was not as strong and the confidence interval included unity (OR = 0.85, 95% CI 0.43-1.68). A logistic model that controlled for age at first pregnancy, number of live births, age, and county of residence increased the odds ratio to 0.97 for a multiple last birth. The current study does not support an association between multiple births and maternal risk of breast cancer.     

Paternal Occupational Lead Exposure and Pregnancy Outcome

Abstract

Self-reported reproductive histories of male employees of a lead-zinc smelter were related to pre-conception measures of lead exposure to examine associations between paternal occupational lead exposure and adverse pregnancy outcome The participants reported 2,021 pregnancies which resulted in 1,684 normal live births, 12 stillbirths, 30, birth defects, 203 spontaneous abortions, and 92 “other” outcomes. Birth defects and stillbirths were combined for the analysis. The risk of a stillbirth or birth defect was elevated for pre-conception employment in a high-lead-exposure compared with a low-lead exposure job (odds ratio = 2.7, 95,% confidence interval = 0.7, 9.6). A similar risk was found for pre-conception blood lead levels of 25–39 μg/dL and ≥40μg/dL when compared With blood lead)level of <25μg/dL(OR = 2.9,95% CI = 0.6, 13.3 and OR = 2.5,95% CI = 0.5,11.6, respecdvely). No association was found between pre-conception lead exposure and spontaneous abortion. A relatively low response rate to the questiollnaire and potentially erroneous reporting of reproductive outcome by male workers are limitations of the study.