Low birthweight at term and the timing of fetal exposure to maternal smoking.

OBJECTIVES. This study was undertaken to evaluate the risk of small-for-gestational-age birth for women who stop smoking or begin to smoke during pregnancy. METHODS. Women with term singleton pregnancies from a hospital-based cohort of 11,177 were classified as (1) nonsmokers; (2) smoked throughout pregnancy; (3) smoked during first trimester only; (4) smoked during first and second trimesters only; and (5) smoked during second and third trimesters or during third trimester only. Risk of small-for-gestational-age birth according to smoking category was estimated and adjusted for confounding factors by logistic regression. RESULTS. Women who stopped smoking by the third trimester were not at increased risk of small-for-gestational-age birth compared with nonsmokers. Women who began smoking during the second or third trimester had an elevated risk of small-for-gestational-age birth (odds ratio [OR] = 1.83; 95% confidence interval [CI] = 1.25, 2.67) similar to that for women who smoked throughout pregnancy (OR = 2.20; 95% CI = 1.90, 2.54). Risk of small-for-gestational-age birth increased with the number of cigarettes smoked during the third trimester. CONCLUSIONS. It is during the third trimester that smoking retards fetal growth, presenting a compelling opportunity for smoking cessation interventions. Programs must emphasize the importance of not resuming smoking late in pregnancy.     

Maternal cigarette smoking and the risk of tubal pregnancy.

The association between maternal smoking and the occurrence of tubal pregnancy was evaluated in a population-based case-control study of members of the Group Health Cooperative of Puget Sound, Seattle, Washington. Women hospitalized with tubal pregnancy from October 1981 through September 1986 (n = 274) were compared with reproductive-age women who were at risk of becoming pregnant during the same time period (n = 727). The relative risk of tubal pregnancy associated with ever having smoked cigarettes was 1.3 (95% confidence interval (CI) 1.0-1.8). Compared with women who had never smoked, those who smoked at the time of conception had a 40% increase in the risk of tubal pregnancy (95% CI 1.0-2.0). These results support earlier epidemiologic and nonepidemiologic reports of a greater risk of tubal pregnancy associated with current or recent maternal cigarette smoking.     

Cigarettes, coffee, and preterm premature rupture of the membranes.

Premature (prior to 37 completed weeks of gestation) rupture of the membranes (preterm PROM) is one of the most common underlying causes of preterm delivery. However, there have been few epidemiologic studies of this obstetric complication. The authors studied the relation of maternal cigarette smoking and coffee consumption to both preterm PROM and spontaneous preterm labor not complicated by premature rupture of the membranes (preterm NONPROM) in a large cross-sectional data base. The 307 preterm PROM and 488 preterm NONPROM cases who delivered during 1977-1980 at the Boston Hospital for Women were compared with 2,252 randomly selected women who delivered at term at that institution. Multiple logistic regression techniques were used to derive maximum likelihood estimates of adjusted odds ratios (OR) and 95% confidence intervals (CI). After confounders had been adjusted for, the relative risk of preterm PROM for women who reported ever having smoked during pregnancy, as compared with nonsmokers, was 1.6 (95% CI 1.1-2.4). However, no gradient between the number of cigarettes smoked per day and the risk of preterm PROM was observed. Similar results were observed for preterm NONPROM. Women who consumed three or more cups of coffee daily during the first trimester had a 2.2-fold greater risk of preterm PROM than did women who drank two or fewer cups (95% CI 1.5-3.3). Among coffee drinkers, there was some evidence of a linear trend in the risk of preterm PROM as coffee consumption increased. Consumption of three or more cups of coffee per day was less strongly associated with the occurrence of preterm NONPROM (adjusted OR = 1.4, 95% CI 1.0-1.9).     

Risk factors for ectopic pregnancy: a comprehensive analysis based on a large case-control,population-based study in France

This case-control study was associated with a regional register of ectopic pregnancy between 1993 and 2000 in France. It included 803 cases of ectopic pregnancy and 1,683 deliveries and was powerful enough to investigate all ectopic pregnancy risk factors. The main risk factors were infectious history (adjusted attributable risk = 0.33; adjusted odds ratio for previous pelvic infectious disease = 3.4, 95% percent confidence interval (CI): 2.4, 5.0) and smoking (adjusted attributable risk = 0.35; adjusted odds ratio = 3.9, 95% CI: 2.6, 5.9 for >20 cigarettes/day vs. women who had never smoked). The other risk factors were age (associated per se with a risk of ectopic pregnancy), prior spontaneous abortions, history of infertility, and previous use of an intrauterine device. Prior medical induced abortion was associated with a risk of ectopic pregnancy (adjusted odds ratio = 2.8, 95% CI: 1.1, 7.2); no such association was observed for surgical abortion (adjusted odds ratio = 1.1, 95% CI: 0.8, 1.6). The total attributable risk of all the factors investigated was 0.76. As close associations were found between ectopic pregnancy and infertility and between ectopic pregnancy and spontaneous abortion, further research into ectopic pregnancy should focus on risk factors common to these conditions. In terms of public health, increasing awareness of the effects of smoking may be useful for ectopic pregnancy prevention.     

Breastfeeding duration and perinatal cigarette smoking in a population-based cohort

OBJECTIVES: We examined the association between breastfeeding duration and maternal smoking before, during, and after pregnancy. METHODS: Data from the 2000-2001 Oregon Pregnancy Risk Assessment Monitoring System were used. Early weaning was defined as not breastfeeding at 10 weeks postpartum. RESULTS: At 10 weeks after pregnancy, 25.7% of mothers who initiated breastfeeding no longer breastfed. After controlling for confounders, quitters (mothers who quit smoking during pregnancy and maintained quit status after pregnancy) and postpartum relapsers (mothers who quit smoking during pregnancy and resumed smoking after delivery) did not have significantly higher risk for early weaning than nonsmokers. However, persistent smokers (mothers who smoked before, during, and after pregnancy) were 2.18 times more likely not to breastfeed at 10 weeks (95% confidence interval=1.52, 2.97). Women who smoked 10 or more cigarettes per day postpartum (i.e., heavy postpartum relapsers and heavy persistent smokers) were 2.3-2.4 times more likely to wean their infants before 10 weeks than were nonsmokers. CONCLUSIONS: Maternal smoking is associated with early weaning. Stopping smoking during pregnancy and decreasing the number of cigarettes smoked postpartum may increase breastfeeding duration.     

The sociodemographic pattern of tobacco cessation in the 1980s: results from a panel study of living condition surveys in Sweden.

STUDY OBJECTIVES: To analyse the factors that determined whether or not people were successful in quitting tobacco during the 1980s in Sweden. DESIGN: A logistic regression model was used for the analyses and included: education, marital status, socioeconomic group, social network, physical activities, cigarette consumption, and years spent smoking as independent variables. Men and women were analysed separately for smoking. A specific univariate analysis was also performed for men who used snuff. SETTING: Sweden. PARTICIPANTS: A panel of 5104 randomised people aged 16-84 years was interviewed in 1980-81 and followed up in 1988-89 in the survey of living conditions undertaken by Statistics Sweden. The participation rate was 86%. The panel included 1546 men and women who were daily smokers. There were 418 daily users of snuff among the men, and 129 men both smoked and used snuff. MAIN RESULTS: Together 26% of women and 23% of men had quit smoking. Five percent in both groups were new smokers. Among men, 26% had quit using snuff and 5% had begun smoking. New snuff users among men were 5%. In the multivariate analysis, unmarried men kept smoking at significantly higher rates (OR 2.1; 95% CI 1.2,3.6), as did those men who smoked 11-20 cigarettes/day (OR 2.2; 95% CI 1.5, 3.4), or more than 20 cigarettes/day (OR 2.8; 95% CI 1.4,5.7). Among women, smoking 11-20 cigarettes/day was also a significant factor (OR 3.3; 95% CI 2.1,5.0). Men and women aged 25-44 were significantly more likely to continue smoking (OR = 2.1; 95% CI 1.1,3.7, and 2.2; 95% CI 1.2,4.4) as were those who had smoked for 20 years or more (OR 4.7; 95% CI 2.0,10.8 and OR 2.5; 95% CI 1.1,5.5, respectively). For women, low education (up to grade 9) was also a significant factor (OR = 2.5; 95% CI 1.2,5.1). Among men who had quit using snuff we did not find any values of significance. CONCLUSIONS: One in four smokers had quit during the 1980s and a few started smoking (5%). Some men quit smoking and started using snuff instead. For both sexes, the daily consumption of cigarettes, years spent smoking, and age were the most important determinants of successful quitting. In men, being married/ cohabiting was an important factor as was higher education in women.     

Adolescent males involved in pregnancy:: Associations of forced sexual contact and risk behaviors

Purpose: To determine whether sexually active adolescent males who report being the victim of forced sexual contact and engaging in health risk and problem behaviors are more likely to report getting someone pregnant.

Methods: In 1995, 4159 students in Grades 9–12 in 59 randomly selected public high schools in Massachusetts were anonymously surveyed using the Youth Risk Behavior Survey (YRBS). Data were analyzed for 824 sexually active males. Demographic variables and indicators of sexual behavior, pregnancy, violence, and suicide were assessed. Data were analyzed with multiple logistic regression.

Results: A total of 12.0% of sexually active males reported having been involved in a pregnancy. The proportion of males who reported getting a partner pregnant increased with age. Of the sample, 8.1% gave a history of having had sexual contact against their will. Of those who reported forced sexual contact, 36.4% reported having been involved in a pregnancy; of the males who did not report a history of forced sexual contact, 9.4% were involved in a pregnancy (CV = 0.23; p < 0.00001). Based on multiple logistic regression, forced sexual contact [odds ratio (OR) 3.56; 95% confidence interval (CI) 1.79–7.09], frequency of weapon carrying on school property (OR 1.39; 95% CI 1.18–1.64), number of cigarettes smoked per day (OR 1.22; 95% CI 1.08–1.38), number of sexual partners in the previous 3 months (OR 1.43; 95% CI 1.25–1.65), and condom nonuse at last intercourse (OR 1.80; 95% CI 1.06–3.02) correctly classified 89.9% of the males who were involved in a pregnancy.

Conclusion: This study highlights the association between health-risk and problem behaviors, forced sexual contact, and involvement in pregnancy among sexually active male high school students. In our analysis, a history of forced sexual contact was associated with a higher risk of high school males’ involvement in pregnancy. These results strongly suggest the importance of screening sexually active males for a history of forced sexual intercourse and health risk and problem behaviors in the effort to prevent teenage pregnancy and childbearing.     

Association of petrochemical exposure with spontaneous abortion

OBJECTIVES: To assess the association between petrochemical exposure and spontaneous abortion, a retrospective epidemiological study in a large petrochemical complex in Beijing, China was conducted. METHODS: Plant employment records identified 3105 women who were married, were 20-44 years of age, and had never smoked. Of those, 3070 women (98.8%) reported at least one pregnancy. From this group, 2853 (93%) of the women participated in the study. According to their plant employment record, about 57% of these women workers reported occupational exposure to petrochemicals during the first trimester of their pregnancy. Trained interviewers administered a standardised questionnaire to this group of women and their husbands, collecting information on reproductive history, pregnancy outcomes, employment history, occupational exposure, smoking habits, alcohol consumption, indoor air pollution, and demographic variables. The results from the womens' first pregnancies were analysed. RESULTS: There was a significantly increased risk of spontaneous abortion for women working in all of the production plants with frequent exposure to petrochemicals (8.8%; range of 5.8%-9.8%) compared with those working in nonchemical plants (2.2%; range of 0.0%-7.1%). Also, when a comparison was made between exposed and non-exposed groups within each plant, exposure to petrochemicals was consistently associated with an increased risk of spontaneous abortion. The overall odds ratio (OR) was 2.7 (95% confidence interval (95% CI) 1.8 to 3.9) after adjusting for potential confounders. When the analysis was performed with the exposure information obtained from the women' interview responses for (self reported) exposures, the estimated OR for spontaneous abortions was 2.9 (95% CI 2.0 to 4.0). The analysis was repeated by excluding those 452 women who provided inconsistent reports between recalled exposure and work history, and a comparable risk of spontaneous abortion (OR 2.9; 95% CI 2.0 to 4.4) was found. In analyses for exposure to specific chemicals, an increased risk of spontaneous abortion was found with exposure to most chemicals, and the results for benzene (OR 2.5; 95% CI 1.7 to 3.7), gasoline (OR 1.8; 95% CI 1.1 to 2.9), and hydrogen sulphide (OR 2.3; 95% CI 1.2 to 4.4) were significant. CONCLUSION: An increased risk of spontaneous abortion was found associated with the exposure to petrochemicals, including benzene, gasoline, and hydrogen sulphide.

 

     

Smoking cessation and lung cancer mortality in a cohort of middle-aged Canadian women

PURPOSE: To determine the impact of smoking cessation on lung cancer mortality among women. METHODS: Survival analysis is used to assess the effect of smoking cessation on lung cancer death in the dietary cohort of 49,165 women aged 40 to 59 years enrolled in the Canadian National Breast Screening Study. RESULTS: During an average of 10.3 years of follow-up, 106 women died of lung cancer. The risk of lung cancer mortality among women who quit before age 50 (HR=0.26; 95% CI, 0.13-0.55 among women who quit at ages 40-49) or quit in the previous 10 years (HR=0.39; 95% CI, 0.22-0.69) is substantially lower than the risk among current smokers. Women who quit after age 40 or have quit for less than 20 years are at substantially higher risk of lung cancer mortality compared with never smokers. Both duration of smoking cessation and age at quitting have independent effects on lung cancer mortality, after controlling for number of cigarettes smoked per day and number of years smoked, as well as other potential confounding variables. CONCLUSION: These findings suggest that programs and policies to promote early cessation of smoking and prevention of relapse should be a public health priority.     

The relationship of smoking and ectopic pregnancy.

A case-control study, using data abstracted between 1983 and 1987 from a large perinatal registry, was conducted to explore the relationship between smoking and ectopic pregnancy. Women with ectopic pregnancy (n = 634) seen at University of Illinois Perinatal Network Hospitals were compared to women who were delivered of a single live-born infant (n = 4287). Adjusted for age and race, women who reported smoking during pregnancy had a greater than twofold risk of ectopic pregnancy (Odds Ratio = 2.5, 95% confidence interval = 1.9, 3.2) compared to women who never smoked. The estimated relative risk rose from 1.4 (95% CI = 0.8, 2.5) for a woman smoking fewer than 10 cigarettes a day to 5.0 (95% CI = 2.9, 8.7) at one and a half or more packs of cigarettes per day (p-value for trend less than 0.001). Although further basic and epidemiologic research is necessary, the observed dose-response relation strengthens the argument that smoking may be a causal factor in the development of ectopic pregnancy.     

Effect of smoking during pregnancy on maternal condition and birth outcome--overview of epidemiologic studies

The association between maternal smoking and retarded fetal grow was first time described in 1957, and now is well know. In addition smoking during pregnancy increases risk of spontaneous abortion, placenta previa, abruptio placenta, preterm premature rupture of membranes, stillbirth, preterm delivery and congenital malformations. The risk for most of these conditions has been found to increase with the number of cigarettes smoked and on the other hand women who stopped smoking during pregnancy are at the lower risk for most of those pathologies.     

Smoking patterns and use of cessation interventions during pregnancy

BACKGROUND: Pregnant smokers should be counseled to quit smoking and offered effective cessation interventions. To improve understanding of how best to increase smoking-cessation rates during pregnancy, this study analyzed population-based surveillance data to describe women's smoking patterns and the use of cessation services during pregnancy. METHODS: Data were analyzed from the 2004 and 2005 New Jersey Pregnancy Risk Assessment Monitoring System, a population-based survey of postpartum women (n=4473). Measures of behaviors included the timing of quit relative to the learning of pregnancy, provider assistance, the use of cessation interventions, and barriers to quitting. Analyses were done in 2007 and 2008. RESULTS: An estimated 16.2% (95% CI=15.1, 17.3) of women smoked before pregnancy. Of these, 49.8% quit before entering prenatal care, and 5.2% quit after entering prenatal care. Almost all women reported that their prenatal care provider asked if they smoked, but only 56.7% reported that a provider counseled them to quit smoking. Only 11.5% of women who smoked in late pregnancy used a cessation method, including self-help materials (6.3%); medications (3.9%); face-to-face counseling (1.7%); telephone-based counseling (1.5%); Internet-based counseling (1.3%); and a class or program (1.0%). The most frequently reported barriers to quitting were cravings for a cigarette, stress, and being around people who smoked. CONCLUSIONS: Nearly half of pregnant New Jersey smokers quit before prenatal care, and very few quit later. Few continuing smokers used a smoking-cessation method when trying to quit or cut back. Efforts should be intensified to increase the knowledge, promotion, and referral to effective interventions to help pregnant smokers quit.     

Work schedule during pregnancy and spontaneous abortion

BACKGROUND: There is inconsistent evidence as to whether work schedule (including rotating shifts and night work) can affect reproductive outcomes. METHODS: We investigated the association between work schedule and risk of spontaneous abortion in U.S. nurses. The Nurses' Health Study II is a prospective cohort study established in 1989. In 2001, information about occupational activities and exposures during pregnancy was collected from female nurses for the most recent pregnancy since 1993. Of 11,178 eligible respondents, 9547 (85%) indicated willingness to participate in the occupational study, and 8461 of those (89%) returned the questionnaire, for an overall participation rate of 76%. Of these, 7688 women had pregnancies that were eligible for analysis. RESULTS: Participants reported 6902 live births and 786 (10%) spontaneous abortions. Compared with women who reported usually working "days only" during their first trimester, women who reported usually working "nights only" had a 60% increased risk of spontaneous abortion (RR = 1.6; 95% confidence interval [CI] = 1.3-1.9). A rotating schedule, with or without night shifts, was not associated with an increase in risk (RR = 1.2 [CI = 0.9-1.5] and 1.0 [CI = 0.8-1.2], respectively). Women who reported working more than 40 hours per week during the first trimester were also at increased risk of spontaneous abortion (1.5; 1.3-1.7) compared with women working 21-40 hours, even after adjustment for work schedule. CONCLUSIONS: Nightwork and long work hours may be associated with an increased risk of spontaneous abortion. Further studies are needed to determine whether hormonal disturbances attributed to night work affect pregnancy outcome.     

Changes in Maternal Cigarette Smoking Among Pregnant WIC Participants in Rhode Island

Objectives To describe the relationship between the timing of entry into the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) among pregnant women in Rhode Island (RI) and changes in maternal cigarette smoking (MCS) during pregnancy. Methods MCS data gathered by WIC were analyzed for pregnant women who self-identified as smokers at the onset of pregnancy between the years 2001–2005. Bivariate and multivariate analyses were performed to examine the relationship between timing of WIC entry and both increased and decreased/quit MCS during pregnancy. Results Self-reports from smokers indicated that 9.5% quit smoking, 24.6% decreased MCS, 26.8% experienced no change, 33.5% increased MCS, and 5.6% attempted to quit MCS but failed during pregnancy. The adjusted odds ratio for smokers with 1st trimester WIC entry and increased MCS was 0.64 (95% CI 0.52, 0.79). Among smokers with 1st trimester PNC entry, the adjusted odds ratio for smokers with 1st trimester WIC entry and decreased/quit MCS was 1.51 (95% CI 1.17, 1.96). Conclusions Early WIC entry appears to be associated with improvements in MCS. Participants who entered WIC in the first trimester of pregnancy were less likely to increase smoking during pregnancy, and if they also had first trimester prenatal care, were more likely to decrease/quit smoking compared to those who entered WIC later. Programs that increase the rates of first trimester WIC entry may contribute to lower rates of MCS in the WIC population.     

Parental cigarette smoking and the risk of spontaneous abortion.

Although cigarette smoking is often considered a risk factor for spontaneous abortion, the epidemiologic literature is actually inconsistent. Therefore, the authors examined maternal and paternal smoking and maternal passive smoke exposure using data from a large case-control study of spontaneous abortion (626 cases and 1,300 controls) conducted in Santa Clara County, California, in 1986 and 1987. No excess risk of spontaneous abortion was seen in the 1% of women who smoked an average of more than 20 cigarettes per day in the first trimester. Moderate smokers (11-20 cigarettes per day) had a slightly elevated crude odds ratio of 1.3 (95% confidence interval 0.9-1.9), which was close to unity after adjustment for covariates. Paternal smoking showed a slight crude elevation for moderate and heavy smoking, but no association after adjustment. In contrast, maternal exposure to environmental tobacco smoke for 1 hour or more per day was associated with spontaneous abortion, even after adjustment (odds ratio = 1.5, 95% confidence interval 1.2-1.9). For both maternal direct and environmental exposure, the association appeared to be stronger in second-trimester abortions. Several studies have found stronger associations of smoking with late versus early abortions, perhaps reflecting smoking-associated placental insufficiency and fetal hypoxia.     

Smoking among pregnant women with disabilities

PurposeThe purpose of this study was to examine the prevalence of smoking before, during, and after pregnancy among a representative sample of Massachusetts women with and without disabilities.MethodsData from the 2007 to 2009 Massachusetts Pregnancy Risk Assessment Monitoring System survey were used to estimate the prevalence of smoking by disability status.Main FindingsDisability prevalence was 4.8% (n = 204) among Massachusetts women giving birth during 2007 through 2009. The prevalence of smoking during the 3 months before pregnancy among women with disabilities was 37.3% (95% CI, 28.3–47.2%) compared with 18.3% (95% CI, 16.6–20.1%) among women without disabilities. Similarly, 25.2% (95% CI, 17.3–35.2%) of women with disabilities, compared with 9.4% of women without disabilities (95% CI, 8.1–10.8%), smoked during the last trimester of their pregnancy, and 32.1% of women with disabilities (95% CI, 23.5–42.1%) compared with 12.5% of women without disabilities (95% CI, 11.1–14.1%), smoked after pregnancy. In the multivariate logistic regression models, women with disabilities had significantly higher risks of smoking before, during and after pregnancy than women without disabilities (adjusted relative risk [aRR], 1.7 [95% CI, 1.2–2.2]; aRR, 1.9 [95% CI, 1.3–2.8]; aRR, 1.8 [95% CI, 1.3–2.5], respectively) while adjusting for race/Hispanic ethnicity, marital status, education, age, household poverty status, and infant’s birth year.ImplicationsWomen with disabilities are more likely to smoke before, during, and after their pregnancy and less likely to quit smoking during pregnancy. Efforts to integrate and target pregnant women with disabilities in smoking-cessation programs are vital.     

Maternal Exposures to Cigarette Smoke,Alcohol, and Street Drugs and Neural Tube Defect Occurrence in Offspring

Objectives Cigarettes, alcoholic beverages, and street drugs contain substances potentially toxic to the developing embryo. We investigated whether maternal cigarette smoking, secondhand smoke exposure, and alcohol or street drug use contributed to neural tube defect (NTD) occurrence in offspring. Methods We conducted a population-based case-control study among Mexican American women who were residents of the 14 Texas counties bordering Mexico. Case women had an NTD-affected pregnancy and delivered during 1995–2000. Control women were those who delivered live born infants in the same study area, without an apparent congenital malformation, randomly selected by year and facility. We interviewed women in person, 1–3 months postpartum, to solicit relevant information. Results Nonsmoking mothers exposed to secondhand smoke during the first trimester had an NTD odds ratio (OR) of 2.6 (95% confidence interval (CI) = 1.6, 4.0) compared to those who neither smoked nor were exposed to secondhand smoke. Compared to the referent, the OR among women who smoked less than half a pack a day during the first trimester was 2.2 (95% CI = 1.0, 4.8) and 3.4 (95% CI = 1.2, 10.0) among those who smoked a half pack or more. Adjustment for maternal age, education, body mass index, and folate intake had a negligible effect on results. Alcohol and street drug use had no relation to NTD risk when adjusted for cigarette smoking. Conclusions This study suggests that cigarette smoke including secondhand exposure is not only hazardous to the mother but may also interfere with neural tube closure in the developing embryo.     

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.     

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.     

Factors Associated With Quitting Smoking During Pregnancy Among Women Veterans

IntroductionLittle is known about the rates of smoking among pregnant veterans. Our objective was to examine rates of smoking during pregnancy and factors associated with quitting smoking during pregnancy.MethodsWe used data from a cohort study of pregnant veterans from 15 Veterans Health Administration facilities nationwide. Veterans who reported smoking during pregnancy were included in this analysis. Poisson regression models were used to estimate the relative risk (RR) of quitting smoking during pregnancy.ResultsOverall, 133 veterans reported smoking during pregnancy. Among this group of women who smoked, the average age was 31.6 years, 20% were Black, and 14% were Hispanic/Latino. More than one-half of women (65%) who reported smoking at the start of pregnancy quit smoking during pregnancy. Multivariable models, adjusted for history of deployment and age, indicated that prenatal care initiation at 12 or fewer weeks compared with more than 13 weeks (relative risk [RR], 2.06; 95% confidence interval [CI], 1.18–3.58), living without household smokers compared with any household smokers (RR, 1.58; 95% CI, 1.14–2.17), and first pregnancy (RR, 1.51; 95% CI, 1.17–1.95) were significant predictors of quitting versus persistent smoking during pregnancy.ConclusionsWomen veterans who quit smoking may be different than those who continue to smoke during pregnancy. Establishing prenatal care early in pregnancy, which likely includes counseling about smoking cessation, seems to be an important factor in quitting. Those for whom it is not a first pregnancy and who live with other smokers may especially benefit from such counseling.