Caffeinated beverages, decaffeinated coffee, and spontaneous abortion

Preconception sleep duration, non-daytime work schedules, and incidence of spontaneous abortion: a prospective cohort study

STUDY QUESTION

To what extent do self-reported sleep duration and non-daytime work schedules in either partner affect the rate of spontaneous abortion (SAB)?

SUMMARY ANSWER

Incidence of SAB had little association with female sleep duration and a modest positive association with male short sleep duration, female work at night, and discrepant work schedules among partners.

WHAT IS KNOWN ALREADY

Several studies have reported an association between short sleep duration in either partner and reproductive health outcomes, including fecundability. Moreover, certain types of female occupational exposures during pregnancy have been associated with an increased risk of SAB. No studies have evaluated SAB risk in relation to male sleep and work schedules, or joint exposures within a couple.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study included 9357 female participants and 2602 of their male partners residing in North America (June 2013 to April 2023).

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants enrolled when they were attempting pregnancy and completed self-administered baseline questionnaires about their average sleep duration and work schedules. Among those who conceived, we ascertained SAB and gestational age at loss via follow-up questionnaires. We used multivariable Cox proportional hazards models with gestational weeks as the time scale to estimate hazard ratios (HRs) and 95% CIs relating SAB with sleep duration and non-daytime work schedules for female and male participants, and the couple. We used inverse probability weighting to account for potential selection bias due to the possibility of differential participation of male partners with respect to the exposures.

MAIN RESULTS AND THE ROLE OF CHANCE

Compared to female participants with recommended sleep (7-8.9 h), those reporting short sleep duration (<6 h) did not have a higher rate of SAB (HR 0.88, 95% CI 0.69, 1.13). Short self-reported sleep duration among male participants was modestly associated with a higher rate of SAB (adjusted and weighted HR 1.30, 95% CI 0.96, 1.75). Female night work at night (adjusted HR 1.19, 95% CI 1.02, 1.38) and male non-daytime work (adjusted and weighted HR 1.26, 95% CI 1.00, 1.59) were associated with modestly higher rates of SAB, whereas female rotating shift work was not (adjusted HR 0.91, 0.78, 1.05) compared with daytime workers. Couples in which work schedules were discrepant had an elevated rate of SAB if the male partner worked a non-daytime shift (adjusted and weighted HR 1.46, 95% CI 1.13, 1.88) compared with couples in which both members worked during the day. The corresponding HR if only the female partner worked a non-daytime shift was 1.21 (95% CI 0.92, 1.58).

LIMITATIONS, REASONS FOR CAUTION

Data on sleep duration and work schedules were based on self-report, which is vulnerable to misclassification, particularly since participants were asked to report their average sleep duration during the past month. Work exposures were heterogeneous, as many different types of employment may require night and shift work and may have different associations with SAB.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings are consistent with previous research indicating that some types of female employment schedules may be associated with SAB incidence. This is the first study to indicate a relationship between SAB and male employment schedules, indicating that discrepant work schedules within a couple might be relevant.

STUDY FUNDING/COMPETING INTEREST(S)

This work was funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development grants R01HD105863 (PIs: L.A.W. and M.L.E.), R01HD086742 (PIs: L.A.W. and E.E.H.), and R21HD072326 (PI: L.A.W.). PRESTO has received in-kind donations from Swiss Precision Diagnostics and Kindara.com for primary data collection. L.A.W. is a consultant for AbbVie, Inc. and the Gates Foundation. M.L.E. is an advisor for and holds stock in Ro, Hannah, Dadi, Underdog, Vseat, & Doveras. The other authors have no competing interests to declare.

TRIAL REGISTRATION NUMBER

N/A.

Relationship between maternal caffeine and coffee intake and pregnancy loss: A grading of recommendations assessment, development, and evaluation-assessed, dose-response meta-analysis of observational studies

Background

Numerous studies report an association between coffee or caffeine consumption and pregnancy loss; however, the nature and strength of this relationship have not been clearly established. Based on recent studies, our meta-analysis aimed to test whether a dose-response relationship between coffee or caffeine consumption and pregnancy loss exists.

Methods

We searched for articles in PubMed, Web of Science, and Scopus published until May 2022. Two independent reviewers extracted data and rated the quality of the evidence using the GRADE approach. We applied a random-effects, one-stage dose-response meta-analysis.

Results

A total of 34 articles (18 cohort studies and 16 case-control studies) were included in this review. Results showed a significantly higher risk of pregnancy loss for coffee consumption before (Pooled ES: 1.21; 95% CI: 1.01-1.43) and during pregnancy (Pooled ES: 1.26; 95% CI: 1.04-1.57), and for coffee consumption during pregnancy in case-control studies (Pooled ES: 1.20; 95% CI: 1.19-6.41). Findings from this meta-analysis demonstrated that caffeine intake during pregnancy was associated with a significantly higher risk of pregnancy loss in cohort (Pooled ES: 1.58; 95% CI: 1.23-2.01) and case-control studies (Pooled ES: 2.39; 95% CI: 1.69-3.37, P < 0.001), respectively. A dose-response analysis suggested that an increase of a cup of coffee per day during pregnancy was associated with 3% increased risk of pregnancy loss; 100 mg of caffeine per day during pregnancy was also associated with 14 and 26% increased risk of pregnancy loss in cohort and case-control studies, respectively. A non-linear dose-response association was observed between coffee intake and the risk of pregnancy loss.

Conclusion

This study confirms that coffee or caffeine consumption raises the risk of pregnancy loss. Researchers are encouraged to conduct more studies to explore the underlying mechanisms and active compounds in coffee and caffeine.

Systematic Review Registration

[www.crd.york.ac.uk/prospero/], identifier [CRD42021267731].

Association between coffee or caffeine consumption and fecundity and fertility: a systematic review and dose-response meta-analysis

Objective

The aim was to investigate whether coffee or caffeine consumption is associated with reproductive endpoints among women with natural fertility (ie, time to pregnancy [TTP] and spontaneous abortion [SAB]) and among women in fertility treatment (ie, clinical pregnancy rate or live birth rate).

Design

This study was a systematic review and dose-response meta-analysis including data from case-control and cohort studies.

Methods

An extensive literature search was conducted in MEDLINE and Embase, with no time and language restrictions. Also, reference lists were searched manually. Two independent reviewers assessed the manuscript quality using the Newcastle-Ottawa Scale (NOS). A two-stage dose-response meta-analysis was applied to assess a potential association between coffee/caffeine consumption and the outcomes: TTP, SAB, clinical pregnancy, and live birth. Heterogeneity between studies was assessed using Cochrane Q-test and I² statistics. Publication bias was assessed using Egger's regression test.

Results

The pooled results showed that coffee/caffeine consumption is associated with a significantly increased risk of SAB for 300 mg caffeine/day (relative risk [RR]: 1.37, 95% confidence interval [95% CI]: 1.19; 1.57) and for 600 mg caffeine/day (RR: 2.32, 95% CI: 1.62; 3.31). No association was found between coffee/caffeine consumption and outcomes of fertility treatment (based on two studies). No clear association was found between exposure to coffee/caffeine and natural fertility as measured by fecundability odds ratio (based on three studies) or waiting TTP (based on two studies).

Conclusion

Results from this meta-analysis support the growing evidence of an association between coffee/caffeine intake and the risk of SAB. However, viewing the reproductive capacity in a broader perspective, there seems to be little, if any, association between coffee/caffeine consumption and fecundity. In general, results from this study are supportive of a precautionary principle advised by health organizations such as European Food Safety Authority (EFSA) and World Health Organization (WHO), although the advised limit of a maximum of two to three cups of coffee/200-300 mg caffeine per day may be too high.

Caffeine citrate - Is it a silver bullet in neonatology?

Caffeine citrate is one of the most prescribed drug in the present day NICU for apnea. Its efficacy, tolerability, wide therapeutic index and safety margin has made it the drug of choice among the methylxanthines. Its therapeutic uses in apnea of prematurity, mechanical ventilation, bronchopulmonary dysplasia has made it a "silver bullet" in neonatology. However, there are still controversies surrounding this drug. This review is aimed to update the reader about the basic pharmacology, current therapeutic uses, adverse effects, controversies as well as present and future research of caffeine.

Factors associated with spontaneous abortion: a cross-sectional study of Chinese populations

Background

Spontaneous abortion (SA) is one of the prevalent negative reproductive outcomes among women around the world, which is a great challenge faced by maternal health promotion. The present study is aimed to explore the association between SA and socioeconomic status (SES) and provides reference for policy makers to improve strategies on maternal health promotion.

Methods

A cross-sectional analysis was conducted with baseline data from a large-scale population-based cohort study of 0.5 million people from 10 geographically diverse areas of China recruited from 2004 to 2008. The study collected data from 84,531 women aged 35–45 years old in the baseline survey of China Kadoorie Biobank. Participants were interviewed using a standardized questionnaire, and information on demographic-socioeconomic as well as reproductive health status was collected. Odds ratios (OR) with 95% CI, estimated by a multistep logistic regression, were used to approximate the associations between SA occurrence and characteristics of SES. A stratification analysis was also applied to find out how SES influenced women’s reproductive health outcomes differently between rural and urban areas. The model was adjusted for age at study date, tea consumption, alcohol consumption, cigarette smoking, and number of induced abortion.

Results

The risk of SA in rural was 1.68 times greater than in urban (AOR = 1.68, 95%CI: 1.54–1.84). Women with high income had a decreased risk of SA when compared with that of women with low income (AOR = 0.90, 95%CI: 0.84–0.97). Compared with women in low educational attainment, women in higher educational attainment had a lower prevalence of SA (AOR = 0.90, 95%CI: 0.82–0.98). The risk of SA only reduced in factory worker (AOR = 0.59, 95%CI: 0.53–0.66) and professional worker (AOR = 0.75, 95%CI: 0.66–0.84) compared with agriculture and related workers. After stratifying by rural/urban, the association between income and SA in urban (AOR = 0.88, 95%CI: 0.78–0.99) was stronger than that in rural (AOR = 0.92, 95%CI: 0.84–1.00). Association between education and SA was found in urban (AOR = 0.66, 95%CI: 0.55–0.78) but not in rural (AOR = 1.05, 95%CI: 0.34–1.17), and there was no difference on how occupation impacted SA among women between the two subgroups.

Conclusions

Generally women with lower SES status had a higher risk of SA. Lower income and educational attainment were inversely associated with the risk of SA. Women with agricultural and related work had a significantly higher prevalence of SA. Interventions could be targeted more on women with low SES to increase both health profits as well as economic gains for health programs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12978-017-0297-2) contains supplementary material, which is available to authorized users.

Pre-pregnancy caffeine and caffeinated beverage intake and risk of spontaneous abortion

PURPOSE

To investigate the relation between pre-pregnancy caffeine and caffeinated beverage intake and risk of spontaneous abortion (SAB).

METHODS

Our prospective cohort study included 15,590 pregnancies from 11,072 women with no history of SAB in the Nurses' Health Study II (1991-2009). Beverage intake was assessed every 4 years using a validated questionnaire. Pregnancies were self-reported with case pregnancies lost spontaneously at <20 weeks gestation. Multivariable log-binomial regression models with generalized estimating equations were used to estimate the relative risks (RRs) and 95 % confidence intervals (CIs).

RESULTS

There was a positive linear trend across categories of pre-pregnancy caffeine intake and risk of SAB such that women consuming >400 mg/day had 1.11 (95 % CI 0.98, 1.25) times the risk of SAB compared to women consuming <50 mg/day (p trend = 0.05). Total coffee intake had a positive, linear association with SAB. Compared to women with no pre-pregnancy coffee intake, women consuming ≥4 servings/day had a 20 % (6, 36 %) increased risk of SAB (p trend = 0.01). There was no difference in the association between caffeinated and decaffeinated coffee and risk of SAB. Pre-pregnancy intake of caffeinated tea, caffeinated soda, and decaffeinated soda had no association with SAB.

CONCLUSIONS

Pre-pregnancy coffee consumption at levels ≥4 servings/day is associated with increased risk of SAB, particularly at weeks 8-19.

Exposure to Power-Frequency Magnetic Fields and the Risk of Infertility and Adverse Pregnancy Outcomes: Update on the Human Evidence and Recommendations for Future Study Designs

Infertility and adverse pregnancy outcomes are significant public health concerns with global prevalence. Over the past 35 years, research has addressed whether exposure to power-frequency magnetic fields is one of the etiologic factors attributed to these conditions. However, no apparent authoritative reviews on this topic have been published in the peer-reviewed literature for nearly 15 years. This review provides an overview and critical analysis of human studies that were published in the peer-reviewed literature between 2002 and July 2015. Using PubMed, 13 epidemiology studies published during this time frame that concern exposure to magnetic fields and adverse prenatal (e.g., miscarriage), neonatal (e.g., preterm birth or birth defects), and male fertility (e.g., poor semen quality) outcomes were identified. Some of these studies reported associations whereas others did not, and study design limitations may explain these inconsistencies. Future investigations need to be designed with these limitations in mind to address existing research gaps. In particular, the following issues are discussed: (1) importance of selecting the appropriate study population, (2) need for addressing confounding due to unmeasured physical activity, (3) importance of minimizing information bias from exposure measurement error, (4) consideration of alternative magnetic field exposure metrics, and (5) implications and applications of personal exposure data that are correlated within female-male couples. Further epidemiologic research is needed, given the near ubiquitous exposures to power-frequency magnetic fields in the general population.

Maternal caffeine intake during pregnancy and risk of pregnancy loss: a categorical and dose-response meta-analysis of prospective studies

OBJECTIVE

To assess the association between maternal caffeine intake and risk of pregnancy loss using a systematic review and meta-analysis.

DESIGN

Categorical and dose-response meta-analysis of prospective studies.

SETTING

Relevant articles were identified by searching MEDLINE and SCOPUS databases through 30 January 2015. Two authors independently extracted information from eligible studies. Random-effects models were used to derive the summary relative risks (RR) and corresponding 95% CI for specific categories of caffeine consumption and for a continuous association using generalized least-squares trend estimation.

SUBJECTS

A total of 130 456 participants and 3429 cases in fourteen included studies.

RESULTS

Compared with the reference category with no or very low caffeine intake, the RR (95% CI) of pregnancy loss was 1·02 (0·85, 1·24; I(2)=28·3%) for low intake (50-149 mg/d), 1·16 (0·94, 1·41; I 2=49·6%) for moderate intake (150-349 mg/d), 1·40 (1·16, 1·68; I(2)=18·6%) for high intake (350-699 mg/d) and 1·72 (1·40, 2·13; I(2)=0·0%) for very high intake (≥ 700 mg/d). In the dose-response analysis, each 100 mg/d increment in maternal caffeine intake (~1 cup of coffee) was associated with 7% (95% CI 3%, 12%) higher risk of pregnancy loss. Our results may have been affected by publication bias, but the association remained significant for the subset of larger studies. Furthermore, adjustment for smoking and pregnancy symptoms may have been incomplete, potentially resulting in residual confounding.

CONCLUSIONS

Albeit inconclusive, higher maternal caffeine intake was associated with a higher risk of pregnancy loss and adherence to guidelines to avoid high caffeine intake during pregnancy appears prudent.

A meta-analysis of risk of pregnancy loss and caffeine and coffee consumption during pregnancy

BACKGROUND

Previous reports of the relationship between pregnancy loss and caffeine/coffee consumption have been inconsistent.

OBJECTIVES

To evaluate the association between pregnancy loss and caffeine and coffee consumption.

SEARCH STRATEGY

PubMed was searched for reports published before September 2014, with the keywords "caffeine," "coffee," "beverage," "miscarriage," "spontaneous abortion," and "fetal loss."

SELECTION CRITERIA

Case-control and cohort studies were included when they had been reported in English, the exposure of interest was caffeine/coffee consumption during pregnancy, the outcome of interest was spontaneous abortion or fetal death, and multivariate-adjusted odds ratios (ORs) or risk ratios were provided or could be calculated.

DATA COLLECTION AND ANALYSIS

Data were extracted and combined ORs calculated.

MAIN RESULTS

Overall, 26 studies were included (20 of caffeine and eight of coffee). After adjustment for heterogeneity, caffeine consumption was associated with an increased risk of pregnancy loss (OR 1.32, 95% confidence interval [CI] 1.24-1.40), as was coffee consumption (OR 1.11, 95% CI 1.02-1.21). A dose-response analysis suggested that risk of pregnancy loss rose by 19% for every increase in caffeine intake of 150 mg/day and by 8% for every increase in coffee intake of two cups per day.

CONCLUSIONS

Consumption of caffeine and coffee during pregnancy seems to increase the risk of pregnancy loss.

Caffeine and caffeinated beverage consumption and risk of spontaneous abortion

STUDY QUESTION

Is caffeine and caffeinated beverage consumption associated with the risk of spontaneous abortion (SAB)?

SUMMARY ANSWER

While preconceptional caffeine consumption was not materially associated with an increased risk of SAB, consumption during early pregnancy was associated with a small increased risk of SAB, although the relation was not linear.

WHAT IS KNOWN ALREADY

Caffeine has been hypothesized as a risk factor for SAB since the 1980s; however, results from previous studies have been conflicting.

STUDY DESIGN, SIZE, DURATION

This prospective cohort study included 5132 Danish women planning pregnancy and enrolled from 2007 to 2010.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were women who conceived after entry into the Snart-Gravid cohort and who were aged 18-40, in a stable relationship with a male partner, and did not use fertility treatments to conceive. Women reported their daily caffeine and caffeinated beverage consumption on questionnaires before conception and during early pregnancy. All exposure measurements were prospective with respect to outcome ascertainment. We estimated hazard ratios (HRs) of SAB for categories of caffeine consumption in milligrams (mg) per day and the corresponding 95% confidence intervals (CIs) using Cox proportional hazards regression models with gestational weeks as the time scale.

MAIN RESULTS AND THE ROLE OF CHANCE

There were 732 women (14.3%) who were identified as having a SAB. In the preconceptional period, caffeine consumption was not materially associated with SAB risk (HR comparing ≥300 with <100 mg/day: 1.09; 95% CI: 0.89, 1.33). In early pregnancy, the HRs for 100-199, 200-299 and ≥300 mg/day of caffeine consumption were 1.62 (95% CI: 1.19, 2.22), 1.48 (95% CI: 1.03, 2.13) and 1.23 (95% CI: 0.61, 2.46), respectively, compared with that for <100 mg/day.

LIMITATIONS, REASONS FOR CAUTION

The observed results may be affected by non-differential exposure misclassification, reverse causation and residual confounding.

WIDER IMPLICATIONS OF THE FINDINGS

This is the largest study to date of prospectively measured, preconception caffeine consumption and risk of SAB. We were able to reduce the likelihood of differential left truncation bias and recall bias present in other analyses.

STUDY FUNDING/COMPETING INTERESTS

Snart-Gravid was funded by the NICHD (R21-050264). Dr. Hahn's work was funded in part by the BU Reproductive, Perinatal, and Pediatric Epidemiology Training Grant NIH #T32HD052458. There are no competing interests.

Preconception care: caffeine, smoking, alcohol, drugs and other environmental chemical/radiation exposure

INTRODUCTION

As providing health education, optimizing nutrition, and managing risk factors can be effective for ensuring a healthy outcome for women and her yet un-conceived baby, external influences play a significant role as well. Alcohol, smoking, caffeine use and other similar lifestyle factors, have now become an integral part of the daily life of most men and women, who use/misuse one or more of these harmful substances regularly despite knowledge of their detrimental effects. The adverse health outcomes of these voluntary and involuntary exposures are of even greater concern in women of child bearing age where the exposure has the potential of inflicting harm to two generations. This paper is examining the available literature for the possible effects of caffeine consumption, smoking, alcohol or exposure to chemicals may have on the maternal, newborn and child health (MNCH).

METHODS

A systematic review and meta-analysis of the evidence was conducted to ascertain the possible impact of preconception usage of caffeine, tobacco, alcohol and other illicit drugs; and exposure to environmental chemicals and radiant on MNCH outcomes. A comprehensive strategy was used to search electronic reference libraries, and both observational and clinical controlled trials were included. Cross-referencing and a separate search strategy for each preconception risk and intervention ensured wider study capture.

RESULTS

Heavy maternal preconception caffeine intake of >300 mg/d significantly increase the risk of a subsequent fetal loss by 31% (95% CI: 8-58%). On the other hand, preconception alcohol consumption leads to non-significant 30% increase in spontaneous abortion (RR 1.30; 95% CI: 0.85-1.97). Preconception counselling can lead to a significant decrease in the consumption of alcohol during the first trimester (OR 1.79; 95% CI: 1.08-2.97). Periconception smoking, on the other hand, was found to be associated with an almost 3 times increased risk of congenital heart defects (OR 2.80; 95% CI 1.76-4.47). While the review found limited evidence of preconception environmental exposure on maternal, newborn and child health outcomes, occupational exposure in female radiation workers before conception showed an increased impact in risk of early miscarriages.

CONCLUSION

Identification of substance abuse and environmental history during preconception period provides an opportunity to assist women in reducing major health risks and identify key determinants of healthy pregnancy. Studies have shown that the aversion and prevention of exposure feasibility can play an important role in improving the health of women and their families, however, the results should be interpreted with great caution as there were few studies in each section. Therefore, there is a need for more rigorous studies to test the hypotheses.

Coffee: biochemistry and potential impact on health

This article reviews the diversity of compounds found in coffee beans, the effect of roasting and the potential impact of coffee beverage on health.

Spontaneous abortion and a diet drug containing caffeine and ephedrine: a study within the Danish national birth cohort

Background

Medications may be consumed periconceptionally before a woman knows she is pregnant. In this study, the authors evaluate the association of a prescription diet drug (Letigen) containing ephedrine (20 mg) and caffeine (200 mg) with spontaneous abortion (SAB) in the Danish National Birth Cohort.

Methods

Women were recruited during their first prenatal visit from 1996–2002. Pre-conception and early pregnancy medication use was reported on the enrollment form, and pregnancy outcome was determined by linking the mother's Civil Registration Number to the Medical Birth Registry and the National Hospital Discharge Register. Of 97,903 eligible pregnancies, 4,443 ended in SAB between 5 and 20 completed gestational weeks, inclusive. Letigen use was reported for 565 pregnancies. Cox regression models accounting for left truncation were fit to estimate the effect of pre-conception and early pregnancy Letigen use on SAB.

Principal Findings

The estimated maternal age-adjusted hazard ratio for SAB was 1.1 (95% confidence interval 0.8–1.6) for any periconceptional Letigen use compared to no periconceptional use.

Conclusions

Although Letigen has high levels of caffeine (the recommended 3 pills/day are approximately equivalent to caffeine from 6 cups of coffee), periconceptional use does not appear to be associated with an appreciably increased hazard of clinically recognized SAB.

Food intake and social habits in male patients and its relationship to intracytoplasmic sperm injection outcomes

OBJECTIVE

To investigate the influence of the male partner's lifestyle, including eating and social habits, on semen quality and intracytoplasmic sperm injection (ICSI) success.

DESIGN

Observational study.

SETTING

Private fertility clinic.

PATIENT(S)

Two hundred fifty male patients undergoing ICSI cycles.

INTERVENTION(S)

We recorded dietary and social habits using a food frequency questionnaire adapted to meet specific study objectives. Evaluation of semen parameters and ICSI outcomes were performed.

MAIN OUTCOME MEASURE(S)

Frequency of intake of food items and social habits were registered on a scale with five categories ranging from no consumption to repeated daily consumption.

RESULT(S)

The sperm concentration was negatively influenced by body mass index (BMI) and alcohol consumption and was positively influenced by cereal consumption and the number of meals per day. The sperm motility was also negatively influenced by BMI, alcohol consumption, and smoking habit, whereas it was positively influenced by the consumption of fruits and cereals. The consumption of alcohol had a negative influence on the fertilization rate. The consumption of red meat as well as being on a weight loss diet had a negative impact on the implantation rate. In addition, the consumption of red meat and being on a weight loss diet had an effect on the pregnancy chance.

CONCLUSION(S)

Couples seeking assisted reproduction treatments must be advised about the drastic effect of both the male and female lifestyle on treatment success.

The relationship between water intake and foetal growth and preterm delivery in a prospective cohort study

BACKGROUND

Interpretation of previous associations between water intake and adverse birth outcomes is challenging given that amount and type of water consumed can be non-specific markers of exposure or underlying behavioural characteristics. We examined the relationship between water intake measures and adverse birth outcomes in participants from three study sites in the United States.

METHODS

Using a prospective cohort study, we examined daily intake of bottled, cold tap, total tap, and total water in relation to birth weight and risk of small-for-gestational-age (SGA) among term births and risk of preterm delivery.

RESULTS

Based on water consumption data collected between 20-24 weeks of gestation, the adjusted mean birth weight was 27 (95% confidence interval [CI]: -34, 87), 39 (95% CI: -22, 99), and 50 (95% CI: -11, 110) grams higher for the upper three total water intake quartiles (> 51-78, > 78-114, and > 114 ounces/day) compared to the lowest quartile (≤ 51 ounces/day). Adjusted birth weight results were similar for bottled water, cold tap water, and total tap water intake. An exposure-response gradient was not detected for either preterm delivery or SGA with increasing total water intake and total tap water intake, but adjusted relative risks for all three upper quartiles were below 1.0 (range: 0.6-0.9) for SGA.

CONCLUSION

These data suggest that high water intake may be associated with higher mean birth weight following adjustment for confounding.

Maternal caffeine consumption and risk of neural tube defects

BACKGROUND

Animal studies demonstrate teratogenic effects of caffeine, whereas human studies are inconclusive.

METHODS

Associations between maternal caffeine consumption and neural tube defects (NTDs) by type of NTD (anencephaly, spina bifida, or encephalocele) were examined using data from the National Birth Defects Prevention Study (NBDPS). Total average daily caffeine from coffee, tea, soda, and chocolate consumption during the year before pregnancy was estimated for 768 mothers of infants with NTDs and 4143 mothers of infants without birth defects who gave birth during 1997 through 2002. Periconceptional use of caffeine-containing medications was evaluated separately. Adjusted odds ratios (OR) and 95% confidence intervals (CI) associated with consumption of total caffeine and each caffeine source were estimated from logistic regression models.

RESULTS

Positive associations were observed between spina bifida and total caffeine consumption (OR 1.4; 95% CI: 1.1-1.9) and each caffeine source except caffeinated tea, which showed a negative association with spina bifida (OR 0.7; 95% CI: 0.6-0.9). Associations with modestly increased risk of NTDs and encephalocele were also observed. The association between caffeine consumption and anencephaly differed by maternal race/ethnicity. No dose effects were found.

CONCLUSIONS

Additional studies should confirm whether women who consume caffeine are at increased risk for pregnancies complicated by NTDs.

Maternal caffeine consumption during pregnancy and the risk of miscarriage: a prospective cohort study

OBJECTIVE

The objective of the study was to examine whether the risk of miscarriage is associated with caffeine consumption during pregnancy after controlling for pregnancy-related symptoms.

STUDY DESIGN

This was a population-based prospective cohort study.

RESULTS

An increasing dose of daily caffeine intake during pregnancy was associated with an increased risk of miscarriage, compared with no caffeine intake, with an adjusted hazard ratio (aHR) of 1.42 (95% confidence interval 0.93 to 2.15) for caffeine intake of less than 200 mg/day, and aHR of 2.23 (1.34 to 3.69) for intake of 200 or more mg/day, respectively. Nausea or vomiting during pregnancy did not materially affect this observed association, nor did the change in intake pattern of caffeine during pregnancy. In addition, the magnitude of the association appeared to be stronger among women without a history of miscarriage (aHR 2.33, 1.48 to 3.67) than that among women with such a history (aHR 0.81, 0.34 to 1.94).

CONCLUSION

Our results demonstrated that high doses of caffeine intake during pregnancy increase the risk of miscarriage, independent of pregnancy-related symptoms.

Risk factors for first trimester miscarriage--results from a UK-population-based case-control study

OBJECTIVE

The aim of this study was to examine the association between biological, behavioural and lifestyle risk factors and risk of miscarriage.

DESIGN

Population-based case-control study.

SETTING

Case-control study nested within a population-based, two-stage postal survey of reproductive histories of women randomly sampled from the UK electoral register.

POPULATION

Six hundred and three women aged 18-55 years whose most recent pregnancy had ended in first trimester miscarriage (<13 weeks of gestation; cases) and 6116 women aged 18-55 years whose most recent pregnancy had progressed beyond 12 weeks (controls).

METHODS

Women were questioned about socio-demographic, behavioural and other factors in their most recent pregnancy.

MAIN OUTCOME MEASURE

First trimester miscarriage.

RESULTS

After adjustment for confounding, the following were independently associated with increased risk: high maternal age; previous miscarriage, termination and infertility; assisted conception; low pre-pregnancy body mass index; regular or high alcohol consumption; feeling stressed (including trend with number of stressful or traumatic events); high paternal age and changing partner. Previous live birth, nausea, vitamin supplementation and eating fresh fruits and vegetables daily were associated with reduced risk, as were feeling well enough to fly or to have sex. After adjustment for nausea, we did not confirm an association with caffeine consumption, smoking or moderate or occasional alcohol consumption; nor did we find an association with educational level, socio-economic circumstances or working during pregnancy.

CONCLUSIONS

The results confirm that advice to encourage a healthy diet, reduce stress and promote emotional wellbeing might help women in early pregnancy (or planning a pregnancy) reduce their risk of miscarriage. Findings of increased risk associated with previous termination, stress, change of partner and low pre-pregnancy weight are noteworthy, and we recommend further work to confirm these findings in other study populations.

Predictors of use and consumption of public drinking water among pregnant women

Disinfection by-products (DBPs) in drinking water may be associated with adverse pregnancy outcomes. However, the results from previous epidemiological studies are not consistent, perhaps in part due to individual variation in water use and consumption. This study was performed to evaluate and describe demographic and behavioral characteristics as predictors of ingested water, showering, bathing, and swimming among pregnant women. Water use and consumption data were collected through telephone interviews with 2297 pregnant women from three geographical sites in the southern United States. The data were analyzed according to demographic, health, and behavioral variables expected to be predictors of water use and thus potential confounding factors relating water use to pregnancy outcome. The candidate predictors were evaluated using backward elimination in regression models. Demographic variables tended to be more strongly predictive of the use and consumption of water than health and behavior-related factors. Non-Hispanic white women drank 0.4 (95% confidence interval (CI) 0.2; 0.7) liters more cold tap water per day than Hispanic women and 0.3 (95% CI 0.1; 0.4) liters more than non-Hispanic black women. Non-Hispanic white women also reported drinking a higher proportion of filtered tap water, whereas Hispanic women replaced more of their tap water with bottled water. Lower socioeconomic groups reported spending a longer time showering and bathing, but were less likely to use swimming pools. The results of this study should help researchers to anticipate and better control for confounding and misclassification in studies of exposure to DBPs and pregnancy outcomes.

Effect of reducing caffeine intake on birth weight and length of gestation: randomised controlled trial

OBJECTIVE

To estimate the effect of reducing caffeine intake during pregnancy on birth weight and length of gestation.

DESIGN

Randomised double blind controlled trial.

SETTING

Denmark.

PARTICIPANTS

1207 pregnant women drinking at least three cups of coffee a day, recruited before 20 weeks' gestation.

INTERVENTIONS

Caffeinated instant coffee (568 women) or decaffeinated instant coffee (629 women).

MAIN OUTCOME MEASURES

Birth weight and length of gestation.

RESULTS

Data on birth weight were obtained for 1150 liveborn singletons and on length of gestation for 1153 liveborn singletons. No significant differences were found for mean birth weight or mean length of gestation between women in the decaffeinated coffee group (whose mean caffeine intake was 182 mg lower than that of the other group) and women in the caffeinated coffee group. After adjustment for length of gestation, parity, prepregnancy body mass index, and smoking at entry to the study the mean birth weight of babies born to women in the decaffeinated group was 16 g (95% confidence interval -40 to 73) higher than those born to women in the caffeinated group. The adjusted difference (decaffeinated group-caffeinated group) of length of gestation was -1.31 days (-2.87 to 0.25).

CONCLUSION

A moderate reduction in caffeine intake in the second half of pregnancy has no effect on birth weight or length of gestation.

TRIAL REGISTRATION

Clinical Trials NCT00131690 [ClinicalTrials.gov].

Coffee and health: a review of recent human research

Coffee is a complex mixture of chemicals that provides significant amounts of chlorogenic acid and caffeine. Unfiltered coffee is a significant source of cafestol and kahweol, which are diterpenes that have been implicated in the cholesterol-raising effects of coffee. The results of epidemiological research suggest that coffee consumption may help prevent several chronic diseases, including type 2 diabetes mellitus, Parkinson's disease and liver disease (cirrhosis and hepatocellular carcinoma). Most prospective cohort studies have not found coffee consumption to be associated with significantly increased cardiovascular disease risk. However, coffee consumption is associated with increases in several cardiovascular disease risk factors, including blood pressure and plasma homocysteine. At present, there is little evidence that coffee consumption increases the risk of cancer. For adults consuming moderate amounts of coffee (3-4 cups/d providing 300-400 mg/d of caffeine), there is little evidence of health risks and some evidence of health benefits. However, some groups, including people with hypertension, children, adolescents, and the elderly, may be more vulnerable to the adverse effects of caffeine. In addition, currently available evidence suggests that it may be prudent for pregnant women to limit coffee consumption to 3 cups/d providing no more than 300 mg/d of caffeine to exclude any increased probability of spontaneous abortion or impaired fetal growth.

Coffee and fetal death: a cohort study with prospective data

The authors conducted a cohort study within the Danish National Birth Cohort to determine whether coffee consumption during pregnancy is associated with late fetal death (spontaneous abortion and stillbirth). A total of 88,482 pregnant women recruited from March 1996 to November 2002 participated in a comprehensive interview on coffee consumption and potentially confounding factors in pregnancy. Information on pregnancy outcome was obtained from the National Hospital Discharge Register and medical records. The authors detected 1,102 fetal deaths. High levels of coffee consumption were associated with an increased risk of fetal death. Relative to nonconsumers of coffee, the adjusted hazard ratios for fetal death associated with coffee consumption of 1/2-3, 4-7, and > or =8 cups of coffee per day were 1.03 (95% confidence interval (CI): 0.89, 1.19), 1.33 (95% CI: 1.08, 1.63), and 1.59 (95% CI: 1.19, 2.13), respectively. Reverse causation due to unrecognized fetal demise may explain the association between coffee intake and risk of fetal death prior to 20 completed weeks' gestation but not the association with fetal loss following 20 completed weeks' gestation. Consumption of coffee during pregnancy was associated with a higher risk of fetal death, especially losses occurring after 20 completed weeks of gestation.

Evidence-based investigations and treatments of recurrent pregnancy loss

OBJECTIVE

To give an overview of currently used investigations and treatments offered to women with recurrent pregnancy loss (RPL) and, from an evidence-based point of view, to evaluate the usefulness of these interventions.

DESIGN

Ten experts on epidemiologic, genetic, anatomic, endocrinologic, thrombophilic, immunologic, and immunogenetic aspects of RPL discussed methodologic problems threatening the validity of research in RPL during and after an international workshop on the evidence-based management of RPL.

CONCLUSION(S)

Most RPL patients have several risk factors for miscarriage, and an extensive investigation for all major factors should always be undertaken. There is an urgent need for agreement concerning the thresholds for detecting what is normal and abnormal, irrespective of whether laboratory tests or uterine abnormalities are concerned. A series of lifestyle factors should be reported in future studies of RPL because they might modify the effect of laboratory or anatomic risk factors. More and larger randomized controlled trials, including trials of surgical procedures, are urgently needed, and to achieve this objective multiple centers have to collaborate. Current meta-analyses evaluating the efficacy of treatments of RPL are generally pooling very heterogeneous patient populations and treatments. It is recommended that future meta-analyses look at subsets of patients and treatment protocols that are more combinable.

Influence of paternal age on the risk of spontaneous abortion

The frequency of chromosomal anomalies in spermatozoa appears to increase with male age. Because these anomalies play a role in the etiology of spontaneous abortion, an influence of paternal age on risk of spontaneous abortion is plausible but not established. The aim was to characterize this influence in a prospective study among 5,121 California women, who as members of a prepaid health plan were interviewed in 1990 or 1991 when they were less than 13 weeks' pregnant and who were followed until the end of pregnancy. The risk of spontaneous abortion between weeks 6 and 20 of pregnancy was studied using a Cox model adjusted for maternal age. The adjusted hazard ratio of spontaneous abortion associated with paternal age of 35 years or more, compared with less than 35 years, was 1.27 (95% confidence interval: 1.00, 1.61), with no modification by maternal age. Among women aged less than 30 years, the hazard ratio of spontaneous abortion associated with paternal age of 35 years or more was 1.56 for first trimester spontaneous abortion and 0.87 for early second trimester spontaneous abortion (test of interaction, p = 0.25). In conclusion, the risk of spontaneous abortion increased with increasing paternal age, with a suggestion that the association is stronger for first trimester losses.

Environmental and occupational factors affecting fertility and IVF success

Reproductive function has been shown to be sensitive to changes in the physical, psychosocial and chemical environments. Although reproductive effects of occupational exposure to hazardous chemicals have been well documented in the literature, the potential effects of chemical contaminants at levels representative of contemporary exposures in the general population are much less certain. Evidence for adverse effects of exposure to environmental contaminants is more conclusive among the lower animals than for humans where considerable controversy remains. In addition to potential reproductive hazards of exposure to environmental contaminants, there is also evidence for adverse reproductive effects of the physical and psychosocial environments. In this review we focus on the difficulties involved in linking exposure to putative hazardous substances in environmental and occupational settings to adverse reproductive outcomes, especially success of IVF procedures. We highlight the plausibility of adverse events through animal and cell studies and the application of these results to the interpretation of human data. We consider both the male and female partners since it is essentially their combined contributions of gametes which may be affected by chemicals, which lead to successful outcomes.

Maternal Caffeine Consumption and Spontaneous Abortion

Since the 1980s, numerous studies have investigated whether caffeine intake during pregnancy affects the risk of spontaneous abortion. A clear consensus, however, has not been reached. Because of the public health importance of this question, we reviewed the results of 15 epidemiologic studies on this topic, with particular attention to the specific methodologic problems that would generate biased findings. These include selection and recall bias, confounding, several issues pertaining to exposure measurement, and the failure to account for fetal karyotype, caffeine metabolism, the timing of fetal demise, and the possibility that an effect of caffeine may be gestational age-specific. All of the studies reviewed suffer from important methodologic limitations that hinder both the interpretation of each study individually and the comparison of results across studies. Despite the fact that most epidemiologic studies have observed a positive association between maternal caffeine intake and the risk of spontaneous abortion, we conclude that the evidence must be considered to be equivocal, given the biases likely present and the fact that most of the potential biases would tend to overestimate any association. Until studies can overcome these limitations, evidence for a causal link between caffeine and spontaneous abortion will remain inconclusive.

Specific roles of the obstetrician-gynecologist

Obstetrician-gynecologists can play a major role in the prevention, identification, and treatment of substance abuse in women. Maintaining cognizance of abuse potential and consistently using office-screening techniques will identify patients who need assistance. Employing brief interventions at frequent office visits is an effective means of treating many of these patients. Those who do not respond to brief interventions may benefit from referral to an addictionologist. The US Supreme Court recently verified the Fourth Amendment rights of pregnant women by deciding that consent must be obtained to perform drug screening in pregnancy. Obstetrician-gynecologists will need to stay abreast of the changes that occur in their state laws as a result of this decision.

The effect of caffeine consumption and nausea on the risk of miscarriage

Evidence for a harmful effect of caffeine intake on risk of miscarriage (spontaneous abortion) is inconsistent and nausea during pregnancy has been claimed to explain any association seen. The objective of this analysis was to determine whether caffeine consumption both before and during pregnancy influenced the risk of miscarriage in a group of pregnant women in the UK. We examined the association with maternal caffeine intake in a case-control study of 474 nulliparous women. Participants were recruited during the years 1987-89 from the Royal Berkshire Hospital in Reading and from a large group practice situated within the hospital's catchment area. Cases were 160 women with a clinically diagnosed miscarriage and controls were 314 pregnant women attending for antenatal care. Information on coffee/tea/cola consumption and potential confounders was collected by interview and caffeine content was assigned to individual drinks according to published data on caffeine content of beverages. Compared with a maternal caffeine intake of < 151 mg/day, we found evidence that caffeine consumption > 300 mg/day doubled the risk of miscarriage. Adjusted odds ratios were 1.94 [95% CI 1.04, 3.63] for 301-500 mg/day and 2.18 [95% CI 1.08, 4.40] for > 500 mg/day. This effect could not be explained by nausea in pregnancy. Nausea appeared to be strongly independently associated with a reduced risk of miscarriage (test for trend P < 0.0001). There was no evidence that prepregnancy caffeine consumption affected the risk. Our results indicate that high caffeine consumption during pregnancy (>300 mg/day), in particular coffee consumption, is an independent risk factor for increased risk and nausea is an independent protective factor for a lower risk of miscarriage.

Focus on Communications: Communicating the Message: Clarifying the Controversies About Caffeine

Today's "coffee culture" and the widespread availability of caffeine-containing foods and beverages fuel the ongoing study of caffeine and its subsequent coverage by the media. Although the media has become influential in communicating health and nutrition information to the public, coverage of emerging science, such as the study of caffeine, does not necessarily bring clarity or improved understanding for consumers. This article highlights the current knowledge of caffeine's effects on health, with emphasis on the most common areas of interest and confusion. To address persistent misperceptions about caffeine, this article also accentuates the need for nutrition professionals to help put the findings of caffeine research into perspective and suggests practical ways to do this.

The associations of maternal caffeine consumption and nausea with spontaneous abortion

To examine whether maternal caffeine consumption is associated with the risk of spontaneous abortion, we analyzed data from a population-based prospective study. The study population comprised 575 women delivering singleton livebirths and 75 women who had spontaneous abortions. The subjects were predominantly white, middle-class women enrolled before pregnancy. Study participants were traced to delivery of a liveborn, singleton infant or a spontaneous abortion. Of the 71 women who did not experience nausea, 29.6% had a spontaneous abortion, compared with 7.2% of 514 women who did experience nausea. Maternal caffeine consumption before pregnancy, or in women without nausea, did not increase the risk of spontaneous abortion, whereas maternal caffeine consumption during the first trimester after nausea started might increase risk of spontaneous abortion (risk ratio = 5.4, 95% confidence interval = 2.0-14.6 for caffeine consumption > or = 300 mg per day compared with < 20 mg per day). These results suggest that maternal caffeine consumption during pregnancy may influence fetal viability in women with nausea.

Caffeine intake and the risk of first-trimester spontaneous abortion

BACKGROUND

Some epidemiologic studies have suggested that the ingestion of caffeine increases the risk of spontaneous abortion, but the results have been inconsistent.

METHODS

We performed a population-based, case-control study of early spontaneous abortion in Uppsala County, Sweden. The subjects were 562 women who had spontaneous abortion at 6 to 12 completed weeks of gestation (the case patients) and 953 women who did not have spontaneous abortion and were matched to the case patients according to the week of gestation (controls). Information on the ingestion of caffeine was obtained from in-person interviews. Plasma cotinine was measured as an indicator of cigarette smoking, and fetal karyotypes were determined from tissue samples. Multivariate analysis was used to estimate the relative risks associated with caffeine ingestion after adjustment for smoking and symptoms of pregnancy such as nausea, vomiting, and tiredness.

RESULTS

Among nonsmokers, more spontaneous abortions occurred in women who ingested at least 100 mg of caffeine per day than in women who ingested less than 100 mg per day, with the increase in risk related to the amount ingested (100 to 299 mg per day: odds ratio, 1.3; 95 percent confidence interval, 0.9 to 1.8; 300 to 499 mg per day: odds ratio, 1.4; 95 percent confidence interval, 0.9 to 2.0; and 500 mg or more per day: odds ratio, 2.2; 95 percent confidence interval, 1.3 to 3.8). Among smokers, caffeine ingestion was not associated with an excess risk of spontaneous abortion. When the analyses were stratified according to the results of karyotyping, the ingestion of moderate or high levels of caffeine was found to be associated with an excess risk of spontaneous abortion when the fetus had a normal or unknown karyotype but not when the fetal karyotype was abnormal.

CONCLUSIONS

The ingestion of caffeine may increase the risk of an early spontaneous abortion among non-smoking women carrying fetuses with normal karyotypes.

Maternal serum paraxanthine, a caffeine metabolite, and the risk of spontaneous abortion

BACKGROUND

Whether the consumption of caffeine during pregnancy increases the risk of spontaneous abortion is controversial. Prior studies have determined caffeine consumption by questionnaire. We used a biologic marker, such as serum paraxanthine, a metabolite of caffeine, to measure the dose of caffeine.

METHODS

In a nested case-control study, we measured serum paraxanthine in 591 women who had spontaneous abortions at less than 140 days' gestation and in 2558 matched women from the same clinic who gave birth to live infants at 28 weeks' gestation or later and who had serum drawn on the same day of gestation as the women who had abortions. The women were enrolled in the Collaborative Perinatal Project during the period from 1959 to 1966, and serum paraxanthine was measured over 30 years later.

RESULTS

A total of 487 women who had spontaneous abortions (82 percent) and 2087 controls (82 percent) had quantifiable serum paraxanthine concentrations. However, the mean serum paraxanthine concentration was higher in the women who had spontaneous abortions than in the controls (752 vs. 583 ng per milliliter, P<0.001). The odds ratio for spontaneous abortion was not significantly elevated in the women who had serum paraxanthine concentrations of 1845 ng per milliliter or lower, corresponding to the 95th percentile of the matched women. However, the adjusted odds ratio for spontaneous abortion among women with serum paraxanthine concentrations higher than 1845 ng per milliliter, as compared with women who had concentrations below 50 ng per milliliter, was 1.9 (95 percent confidence interval, 1.2 to 2.8).

CONCLUSIONS

Only extremely high serum paraxanthine concentrations are associated with spontaneous abortion. This suggests that moderate consumption of caffeine is unlikely to increase the risk of spontaneous abortion.