Caffeine use during pregnancy: how much is safe?
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Caffeine↗
Biomedical subjects
L Fenster
Publications and source records attributed to L Fenster.
Fetal growth retardation in infants of multiparous and nulliparous women with preeclampsia.
OBJECTIVE: Infants of women with preeclampsia are considered at high risk of fetal growth retardation. The purpose of our study was to determine whether the risk differed by parity. STUDY DESIGN: We compared the outcomes of 133 case patients with preeclampsia (101 nulliparous women and 32 multiparous women) and 132 normotensive control patients (52 nulliparous women and 80 multiparous women) who delivered at Northern California Kaiser Permanente hospitals between 1984 and 1985. RESULTS: Women with preeclampsia were more likely than control patients to deliver a small-for-gestational-age infant (adjusted odds ratio 7.0, 95% confidence interval 2.8 to 18.1). After we controlled for smoking status, age, Quetelet index, and race, multiparous women with preeclampsia were at greater risk of having a small-for-gestational-age infant (adjusted odds ratio 29.4, 95% confidence interval 5.2 to 167.5) than were nulliparous women (adjusted odds ratio 4.1, 95% confidence interval 1.2 to 14.1) when compared with normotensive control patients of similar parity. Although multiparous women with preeclampsia had higher mean arterial pressures and somewhat earlier onsets of elevated mean arterial pressure than nulliparous women with preeclampsia, neither of these variables predicted whether the infants would be small for gestational age. CONCLUSION: Multiparous women with preeclampsia are at higher risk of having an infant with fetal growth retardation than are nulliparous women with preeclampsia.
Adult↗
Employment in electronics manufacturing and risk of spontaneous abortion.
A large case-control study of environmental risk factors for spontaneous abortion was conducted among women living in Santa Clara County, California. Because of the prevalence of electronics production work within this population, a specialized questionnaire was administered to women who self-identified as electronics production workers. Spontaneous abortions were identified from pathology records, and controls were identified from birth certificates. The odds ratio for spontaneous abortion and any electronics production work was 0.94 (95% confidence interval = 0.58, 1.5). Odds ratios for the three main branches of electronics production (semiconductor fabrication, printed circuit board manufacturing, and assembly) were likewise near or below unity. Specific production activities with elevated odds ratios included semiconductor diffusion, parts encapsulation, soldering, and flux removal, although the numbers were small and none of the confidence intervals excluded unity. Limitations of this study included modest statistical power and a potential for nondifferential misclassification of exposures, both of which could bias findings toward the null.
Abortion, Spontaneous↗
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.
Abortion, Spontaneous↗
Is drinking water related to spontaneous abortion? Reviewing the evidence from the California Department of Health Services Studies.
Because preliminary data suggested a relation between risk of spontaneous abortion and tapwater consumption during pregnancy, the California Department of Health Services included questions on prenatal water consumption in all reproductive studies conducted between 1982 and 1988. Results from four of these five retrospective data bases suggest that women abstaining from tapwater or drinking bottled water during the first trimester of pregnancy may be at reduced risk of spontaneous abortion. Fetal resorption frequencies seen in an accompanying toxicology study were consistent with these epidemiologic findings, although not conclusive. Tap and bottled water samples from these study areas were analyzed for agents that might account for these findings. Differences in trace element composition and biological activity were observed, but the reproductive significance of these differences is unknown. This paper presents an overview of these studies, which are presented in detail separately. Three alternative explanations for these findings--bias, chance, and causality--are reviewed.
Abortion, Spontaneous↗
Spontaneous abortions and birth defects related to tap and bottled water use, San Jose, California, 1980-1985.
We recently studied pregnancies occurring during 1980-1985 in four study areas in Santa Clara County, California. Two of the areas were exposed to solvent-contaminated drinking water during 1980 and 1981, and two were unexposed. There was an overall excess of spontaneous abortions among women who reported any tapwater consumption during the first trimester of pregnancy compared with those who reported no tapwater consumption [odds ratio (OR) = 4.0; 95% confidence interval (CI) = 1.8-9.1)], regardless of exposure to the contaminated water. The odds ratio for spontaneous abortion for women reporting any vs no tapwater was 6.9 (95% CI = 2.7-17.7) after adjustment for numerous potential confounders using multiple logistic regression analyses. The elevated odds ratio of spontaneous abortion was seen among tapwater drinkers who used no filters or softener-type filters but not among women who reported use of active filters. Spontaneous abortion rates were reduced in women who reported any vs no bottled water consumption (OR = 0.26; 95% CI = 0.16-0.43). Among women who reported no tapwater consumption, no birth defects occurred among 263 live births; in comparison, among women who reported tapwater consumption, 4% of 908 live births had defects (P = 0.0001). We observed no relation between birth defects and bottled water use.
Abortion, Spontaneous↗
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.
Abortion, Spontaneous↗
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.
Abortion, Spontaneous↗
Potential sources of bias and confounding in environmental epidemiologic studies of pregnancy outcomes.
Biases familiar to all epidemiologists take on new importance when studying spontaneous abortion because of the significance of the timing of exposure during gestation, and because the gestational age at which the pregnancy is recognized may be related to risk factors under study. In this paper, we systematically review the principal biases that might affect epidemiologic studies of pregnancy loss, in the context of a series of studies that found associations between adverse reproductive outcomes and prenatal use of tap or bottled water. These biases relate to availability of subjects for study, exposure opportunity, recall of exposure, recall of disease, and confounding. In one of the studies, the rate of bottled water use changed dramatically over the course of the study period, providing an opportunity to test indirectly for biased recall of exposure. We conclude that a less complete recall of water intake among women with normal pregnancies, as compared with those with spontaneous abortions, may have produced, or increased the magnitude of, the associations seen in these studies.
Bias↗
Moderate maternal and paternal alcohol consumption and the risk of spontaneous abortion.
Maternal alcoholism can lead to the fetal alcohol syndrome in offspring, but the effect of more moderate alcohol consumption during pregnancy remains an issue of concern. Therefore, we analyzed data from a large case-control study of spontaneous abortion (626 cases, 1,300 controls) that ascertained maternal alcohol consumption before and during pregnancy, as well as paternal consumption. Asking when in pregnancy alcohol consumption changed allowed us to calculate a weighted average of the amount consumed weekly during the first trimester. The odds ratio for consumption of seven or more drinks per week was 1.9 [95% confidence interval (CI) = 1.1-3.4] when adjusted for maternal smoking, passive smoking, and maternal age. Data were too sparse to examine higher consumption levels. There was some evidence that cases may have had less opportunity than controls to decrease consumption during their shorter pregnancies, potentially biasing the odds ratio upward. The adjusted odds ratio for any paternal alcohol consumption was 1.2 (CI = 0.93-1.5), with no dose-response effect seen. Among pregnancies in which the mother did not drink, there was no association with paternal drinking.
Abortion, Spontaneous↗
A multivariate analysis of risk factors for preeclampsia.
OBJECTIVE: --To determine, in a multivariate analysis, risk factors for preeclampsia that could be observed early in pregnancy and to establish whether these risk factors are different for nulliparas and multiparas. DESIGN: --A case-control study of preeclampsia. SETTING: --Women who gave birth at Northern California Kaiser Permanente Medical Centers in 1984 and 1985. PARTICIPANTS: --Preeclamptic cases (n = 139) were determined from discharge diagnosis of severe preeclampsia and by confirmation of blood pressures and proteinuria from medical records. Controls (n = 132) were randomly selected women who had no discharge diagnosis of any hypertensive disorder of pregnancy and who had no evidence of hypertension or proteinuria from medical record review. MAIN VARIABLES EXAMINED: --Medical records were abstracted for information regarding maternal age, race, previous pregnancy history, family medical history, socioeconomic status, employment during pregnancy, body mass, and smoking and alcohol consumption. RESULTS: --Multiple logistic regression analyses confirmed that case patients were more likely than control patients to be nulliparous (adjusted odds ratio [OR], 5.4; 95% confidence interval [Cl], 2.8 to 10.3) and that preeclampsia in a previous pregnancy greatly increased the risk in a subsequent one (adjusted OR, 10.8; 95% Cl, 1.2 to 29.1). However, regardless of parity, preeclamptic women were also more likely to be of high body mass (adjusted OR, 1.7; 95% Cl, 1.2 to 6.2), to work during pregnancy (adjusted OR, 2.1; 95% Cl, 1.1 to 4.4), and to have a family history of hypertension (adjusted OR, 1.7; 95% Cl, 0.92 to 3.2). Having a previous history of a spontaneous abortion was protective but only in multiparous women (adjusted OR for multiparas, 0.09; 95% Cl, 0.02 to 0.48). In contrast, being black was a significant risk for preeclampsia but only in nulliparous women (adjusted OR for nulliparas, 12.3; 95% Cl, 1.6 to 100.8). CONCLUSIONS: --There are a number of risk factors for preeclampsia that may be determined early in a woman's pregnancy. Multiparas and nulliparas share certain risk factors but not others. A cohort investigation is needed to determine the ability of these risk factors to predict who develops preeclampsia.
Adult↗
Assessment of reporting consistency in a case-control study of spontaneous abortions.
Reporting consistency was examined in a case-control study of spontaneous abortion in Santa Clara County, California. Each case (n = 100) and two pregnant controls (n = 200), frequency-matched by last menstrual period, were interviewed twice: first after the case's spontaneous abortion (on average, 24 weeks after the last menstrual period) and again after completion of the controls' pregnancies (on average, 48 weeks after the last menstrual period). Because of concern about differential reporting of water consumption in regions with publicized water contamination, interviews included detailed questions about consumption of tap water and bottled water during pregnancy, as well as other exposures. Most factors such as caffeine consumption, cigarette smoking, employment, and pregnancy history were consistently reported between interviews and did not appear to be subject to differential reporting between cases and controls. When variables were examined by univariate analysis, controls deleted reports of tap water consumption (any vs. more) more often than did cases. There was also a suggestion of differential reporting of up to two glasses per day for tap water and bottle water consumption when they were examined as continuous variables. However, the degree of differential reporting was not sufficient to appreciably alter the measures of association between water consumption during pregnancy and spontaneous abortion.
Abortion, Spontaneous↗
Exposure to organic solvents and adverse pregnancy outcome.
In a large case-control study (n = 1,926) of spontaneous abortion (SAB), exposure to solvents was ascertained by a telephone interview that asked about occupational use of 18 specific solvents or products, as well as an open-ended "other" solvent category. The adjusted odds ratio for use of any solvent was 1.1 (0.8, 1.5). Solvents for which at least a doubled crude risk of SAB was found included perchlorethylene (OR = 4.7, 95% CI = 1.1, 21.1), trichloroethylene (OR = 3.1, CI = 0.9, 10.4), and paint thinners (OR = 2.3, CI = 1.0, 5.1). Comparing exposure greater than 10 hours per week versus less did not show consistent dose-response effects. By solvent class, an association was seen with aliphatic solvents (adjusted OR = 1.8, 95% CI = 1.1, 3.0), but there was no dose-response effect by hours of use. Household use of solvent-containing products was generally not strongly associated with SAB, nor did it appear to confound the association seen with occupational use. From this and other studies, occupational exposure to at least some solvents appears associated with SAB. The associations of solvent exposure and fetal growth among liveborn offspring of controls was also examined.
Abortion, Spontaneous↗
A study of the effect of perchloroethylene exposure on semen quality in dry cleaning workers.
The purpose of this investigation was to determine the effects of perchloroethylene (PCE) exposure on human semen quality. We compared the semen quality of 34 dry cleaners with that of 48 laundry workers. We examined the relationships of 17 semen parameters to expired air levels of PCE and to an index of exposure based on job tasks in the last three months. The average sperm concentration was over 80 million for both dry cleaners and laundry workers, but approximately one-quarter of each group was oligospermic. The overall percentage of abnormal forms was similar for the two groups; however, sperm of dry cleaners were significantly more likely to be round (t = -3.29, p = 0.002) and less likely to be narrow (t = 2.35, p = 0.02) than the sperm of laundry workers. These effects were dose-related to expired air levels and to the exposure index after controlling for potential confounders (e.g., heat exposure). The average percent motile sperm for both groups was slightly over 60%; however, sperm of dry cleaners tended to swim with greater amplitude of lateral head displacement (ALH) than those of laundry workers (t = -1.73, p = 0.09), and level of PCE in expired air was a significant predictor of ALH in the multiple regression model (t = 2.00, p = 0.05). In addition, exposure index was a significant negative predictor of the sperm linearity parameter (t = -2.57, p = 0.01). These results suggest that occupational exposures to PCE can have subtle effects on sperm quality. Additional analyses are required to determine whether these effects are associated with changes in fertility.
Adult↗
A study of the effect of perchloroethylene exposure on the reproductive outcomes of wives of dry-cleaning workers.
The purpose of this investigation was to compare the reproductive outcomes of wives of men exposed to perchloroethylene in the dry-cleaning industry compared to those of wives of laundry workers. Seventeen female partners of dry cleaners and 32 partners of laundry workers were interviewed. The number of pregnancies and the standardized fertility ratios were similar between the two groups. Wives of dry cleaners did not have higher rates of spontaneous abortions. However, wives of dry cleaners were more than twice as likely to have a history of attempting to become pregnant for more than 12 months or to have sought care for an infertility problem. Cox proportional hazards models indicated that dry-cleaners' wives had half of the per-cycle pregnancy rate of wives of laundry workers, when controlling for other potential confounders (estimated rate ratio of 0.54, 95% C.I. = 0.23, 1.27).
Adult↗
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.
Abortion, Spontaneous↗
Miscarriage, caffeine, and the epiphenomena of pregnancy: the causal model.
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Abortion, Spontaneous↗
Caffeine consumption during pregnancy and fetal growth.
BACKGROUND: The purpose of this study was to examine the association between maternal caffeine consumption and low birthweight, intrauterine growth retardation, and prematurity, adjusting for multiple confounders. METHODS: Data obtained from birth certificates and interviews on 1,230 women with singleton live births were analyzed to evaluate the potential influence of caffeine consumption during the first trimester on fetal growth. RESULTS: The crude odds ratio for intrauterine growth retardation in infants of women reporting heavy caffeine consumption (greater than 300 mg/day) was 3.86 (95% CI = 1.80, 8.40) which decreased to 2.90 (95% CI = 1.23, 6.87) after controlling for confounding factors. The adjusted odds ratio for low birthweight and heavy maternal caffeine consumption was also elevated (OR = 2.05; 95% CI = 0.86, 4.88). Women who reduced their caffeine intake from greater than 300 mg/day to less than that early in pregnancy had lower risks of delivering infants with either intrauterine growth retardation or low birthweight than women who continued to consume that amount. Preterm delivery appeared to be unrelated to caffeine consumption. CONCLUSIONS: Taken together with studies reporting similar findings, these results suggest that heavy caffeine consumption increases the risk for fetal growth retardation.
Adult↗